[libcamera-devel,v2,1/3] android: generic_camera_buffer: Correct buffer mapping

13479 diff mbox series

buffer_hanlde_t doesn't provide sufficient info to map a buffer
properly. cros::CameraBufferManager enables handling the buffer on
ChromeOS, but no way is provided for other platforms.

Therefore, we put the assumption that planes are in the same buffer
and they are consecutive. This modifies the way of mapping in
generic_camera_buffer with the assumption.

Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
---
 src/android/camera_buffer.h              |  14 ++-
 src/android/camera_stream.cpp            |   4 +-
 src/android/mm/cros_camera_buffer.cpp    |   7 +-
 src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
 4 files changed, 99 insertions(+), 30 deletions(-)

Hi Hiro,

On Wed, Aug 25, 2021 at 01:44:08PM +0900, Hirokazu Honda wrote:
> buffer_hanlde_t doesn't provide sufficient info to map a buffer
> properly. cros::CameraBufferManager enables handling the buffer on
> ChromeOS, but no way is provided for other platforms.
>
> Therefore, we put the assumption that planes are in the same buffer
> and they are consecutive. This modifies the way of mapping in
> generic_camera_buffer with the assumption.
>
> Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
> ---
>  src/android/camera_buffer.h              |  14 ++-
>  src/android/camera_stream.cpp            |   4 +-
>  src/android/mm/cros_camera_buffer.cpp    |   7 +-
>  src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
>  4 files changed, 99 insertions(+), 30 deletions(-)
>
> diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
> index c4e3a9e7..87df2570 100644
> --- a/src/android/camera_buffer.h
> +++ b/src/android/camera_buffer.h
> @@ -11,13 +11,17 @@
>
>  #include <libcamera/base/class.h>
>  #include <libcamera/base/span.h>
> +#include <libcamera/geometry.h>
> +#include <libcamera/pixel_format.h>
>
>  class CameraBuffer final : public libcamera::Extensible
>  {
>  	LIBCAMERA_DECLARE_PRIVATE()
>
>  public:
> -	CameraBuffer(buffer_handle_t camera3Buffer, int flags);
> +	CameraBuffer(buffer_handle_t camera3Buffer,
> +		     libcamera::PixelFormat pixelFormat,
> +		     const libcamera::Size &size, int flags);
>  	~CameraBuffer();
>
>  	bool isValid() const;
> @@ -31,8 +35,12 @@ public:
>  };
>
>  #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION				\
> -CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags)	\
> -	: Extensible(std::make_unique<Private>(this, camera3Buffer, flags)) \
> +CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer,		\
> +			   libcamera::PixelFormat pixelFormat,		\
> +			   const libcamera::Size &size, int flags)	\
> +	: Extensible(std::make_unique<Private>(this, camera3Buffer,	\
> +					       pixelFormat, size,	\
> +					       flags))			\
>  {									\
>  }									\
>  CameraBuffer::~CameraBuffer()						\
> diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> index 61b44183..01909ec7 100644
> --- a/src/android/camera_stream.cpp
> +++ b/src/android/camera_stream.cpp
> @@ -110,7 +110,9 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
>  	 * \todo Buffer mapping and processing should be moved to a
>  	 * separate thread.
>  	 */
> -	CameraBuffer dest(camera3Dest, PROT_READ | PROT_WRITE);
> +	const StreamConfiguration &output = configuration();
> +	CameraBuffer dest(camera3Dest, formats::MJPEG, output.size,
> +			  PROT_READ | PROT_WRITE);
>  	if (!dest.isValid()) {
>  		LOG(HAL, Error) << "Failed to map android blob buffer";
>  		return -EINVAL;
> diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> index e8783ff8..50732637 100644
> --- a/src/android/mm/cros_camera_buffer.cpp
> +++ b/src/android/mm/cros_camera_buffer.cpp
> @@ -20,8 +20,9 @@ class CameraBuffer::Private : public Extensible::Private
>  	LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
>
>  public:
> -	Private(CameraBuffer *cameraBuffer,
> -		buffer_handle_t camera3Buffer, int flags);
> +	Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> +		libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> +		int flags);
>  	~Private();
>
>  	bool isValid() const { return valid_; }
> @@ -46,6 +47,8 @@ private:
>
>  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
>  			       buffer_handle_t camera3Buffer,
> +			       [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> +			       [[maybe_unused]] const libcamera::Size &size,
>  			       [[maybe_unused]] int flags)
>  	: handle_(camera3Buffer), numPlanes_(0), valid_(false),
>  	  registered_(false)
> diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> index b3af194c..0bfdc2ba 100644
> --- a/src/android/mm/generic_camera_buffer.cpp
> +++ b/src/android/mm/generic_camera_buffer.cpp
> @@ -12,6 +12,7 @@
>
>  #include <libcamera/base/log.h>
>
> +#include "libcamera/internal/formats.h"
>  #include "libcamera/internal/mapped_framebuffer.h"
>
>  using namespace libcamera;
> @@ -24,8 +25,9 @@ class CameraBuffer::Private : public Extensible::Private,
>  	LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
>
>  public:
> -	Private(CameraBuffer *cameraBuffer,
> -		buffer_handle_t camera3Buffer, int flags);
> +	Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> +		libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> +		int flags);
>  	~Private();
>
>  	unsigned int numPlanes() const;
> @@ -33,35 +35,89 @@ public:
>  	Span<uint8_t> plane(unsigned int plane);
>
>  	size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> +
> +private:
> +	/* \todo Remove planes_ when it will be added to MappedBuffer */
> +	std::vector<Span<uint8_t>> planes_;
>  };
>
>  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> -			       buffer_handle_t camera3Buffer, int flags)
> +			       buffer_handle_t camera3Buffer,
> +			       libcamera::PixelFormat pixelFormat,
> +			       const libcamera::Size &size, int flags)
>  {
> -	maps_.reserve(camera3Buffer->numFds);
>  	error_ = 0;
> -
> +	/*
> +	 * As Android doesn't offer an API to query buffer layouts, assume for
> +	 * now that the buffer is backed by a single dmabuf, with planes being
> +	 * stored contiguously.
> +	 */
> +	int fd = -1;
>  	for (int i = 0; i < camera3Buffer->numFds; i++) {

unsigned int i

> -		if (camera3Buffer->data[i] == -1)
> +		if (camera3Buffer->data[i] == -1 ||
> +		    camera3Buffer->data[i] == fd) {
>  			continue;
> -
> -		off_t length = lseek(camera3Buffer->data[i], 0, SEEK_END);
> -		if (length < 0) {
> -			error_ = -errno;
> -			LOG(HAL, Error) << "Failed to query plane length";
> -			break;
>  		}
>
> -		void *address = mmap(nullptr, length, flags, MAP_SHARED,
> -				     camera3Buffer->data[i], 0);
> -		if (address == MAP_FAILED) {
> -			error_ = -errno;
> -			LOG(HAL, Error) << "Failed to mmap plane";
> -			break;
> -		}
> +		if (fd != -1)
> +			LOG(HAL, Fatal) << "Discontiguous planes are not supported";

Do we just warn ? Or exit with error ? See the below question

> +		fd = camera3Buffer->data[i];

This assigns fd to the 'next' valid data[i].fd. I might have missed
what is the policy here if we have more than one valid dmabuf fds.

Currently you warn and use the last valid one. I would instead error out,
or warn but use the first available one (even if that would result in
undefined behaviour, or most probably an access to non valid memory when
creating planes below).

Do you have a use case for formats with planes allocated in different
buffers that you need to support ? Or can we error out without causing
regressions ?

> +	}

The loop is pretty convoluted. If I'm not mistaken what you want to
verify is that
1) Either all data[i].fd are the same
2) All but the data[0].fd are -1

Wouldn't it be nicer as

        int fd = camera3Buffer->data[0].fd;
        for (unsigned int i = 1; i < camera3Buffer->numFds; ++i) {
                if (camera3Buffer->data[i].fd != -1)
                        continue;

                if (camera3Buffer->data[i].fd != fd)
                        /* Here I would error out */
        }
        if (fd == -1) {
                /* No valid fds, error out */
        }

> +
> +	if (fd != -1) {

Shouldn't this be fd == -1 ? As in "no valid fd found ?"
If I'm not mistaken checking for fd != -1 should fail all the times as
at least one valid fd should be found. On which platform have you
tested this patch ?

> +		error_ = -EINVAL;
> +		LOG(HAL, Error) << "No valid file descriptor";
> +		return;
> +	}
>
> -		maps_.emplace_back(static_cast<uint8_t *>(address),
> -				   static_cast<size_t>(length));
> +	const auto &info = libcamera::PixelFormatInfo::info(pixelFormat);
> +	if (!info.isValid()) {
> +		error_ = -EINVAL;
> +		LOG(HAL, Error) << "Invalid pixel format: "
> +				<< pixelFormat.toString();
> +		return;
> +	}

We could check this at the very beginning of the function and avoid
looping on fds if the format is invalid.

> +
> +	off_t bufferLength = lseek(fd, 0, SEEK_END);
> +	if (bufferLength < 0) {
> +		error_ = -errno;
> +		LOG(HAL, Error) << "Failed to get buffer length";
> +		return;
> +	}
> +
> +	void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> +	if (address == MAP_FAILED) {
> +		error_ = -errno;
> +		LOG(HAL, Error) << "Failed to mmap plane";
> +		return;
> +	}
> +	maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> +
> +	const unsigned int numPlanes = info.numPlanes();
> +	planes_.resize(numPlanes);
> +	unsigned int offset = 0;
> +	for (unsigned int i = 0; i < numPlanes; ++i) {
> +		/*
> +		 * \todo Remove if this plane size computation function is
> +		 * added to PixelFormatInfo.
> +		 */
> +		const unsigned int vertSubSample = info.planes[i].verticalSubSampling;
> +		const unsigned int stride = info.stride(size.width, i, 1u);
> +		const unsigned int planeSize =
> +			stride * ((size.height + vertSubSample - 1) / vertSubSample);
> +
> +		planes_[i] = libcamera::Span<uint8_t>(
> +			static_cast<uint8_t *>(address) + offset, planeSize);
> +
> +		if (bufferLength < offset + planeSize) {
> +			error_ = -EINVAL;
> +			LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> +					<< ", buffer length=" << bufferLength
> +					<< ", offset=" << offset
> +					<< ", size=" << planeSize;
> +			return;
> +		}
> +		offset += planeSize;
>  	}
>  }
>
> @@ -71,15 +127,15 @@ CameraBuffer::Private::~Private()
>
>  unsigned int CameraBuffer::Private::numPlanes() const
>  {
> -	return maps_.size();
> +	return planes_.size();
>  }
>
>  Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
>  {
> -	if (plane >= maps_.size())
> +	if (plane >= planes_.size())
>  		return {};
>
> -	return maps_[plane];
> +	return planes_[plane];
>  }
>
>  size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const
> --
> 2.33.0.rc2.250.ged5fa647cd-goog
>

Ups,

On Wed, Aug 25, 2021 at 10:35:07AM +0200, Jacopo Mondi wrote:
> Hi Hiro,
>
> On Wed, Aug 25, 2021 at 01:44:08PM +0900, Hirokazu Honda wrote:
> > buffer_hanlde_t doesn't provide sufficient info to map a buffer
> > properly. cros::CameraBufferManager enables handling the buffer on
> > ChromeOS, but no way is provided for other platforms.
> >
> > Therefore, we put the assumption that planes are in the same buffer
> > and they are consecutive. This modifies the way of mapping in
> > generic_camera_buffer with the assumption.
> >
> > Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
> > ---
> >  src/android/camera_buffer.h              |  14 ++-
> >  src/android/camera_stream.cpp            |   4 +-
> >  src/android/mm/cros_camera_buffer.cpp    |   7 +-
> >  src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
> >  4 files changed, 99 insertions(+), 30 deletions(-)
> >
> > diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
> > index c4e3a9e7..87df2570 100644
> > --- a/src/android/camera_buffer.h
> > +++ b/src/android/camera_buffer.h
> > @@ -11,13 +11,17 @@
> >
> >  #include <libcamera/base/class.h>
> >  #include <libcamera/base/span.h>
> > +#include <libcamera/geometry.h>
> > +#include <libcamera/pixel_format.h>
> >
> >  class CameraBuffer final : public libcamera::Extensible
> >  {
> >  	LIBCAMERA_DECLARE_PRIVATE()
> >
> >  public:
> > -	CameraBuffer(buffer_handle_t camera3Buffer, int flags);
> > +	CameraBuffer(buffer_handle_t camera3Buffer,
> > +		     libcamera::PixelFormat pixelFormat,
> > +		     const libcamera::Size &size, int flags);
> >  	~CameraBuffer();
> >
> >  	bool isValid() const;
> > @@ -31,8 +35,12 @@ public:
> >  };
> >
> >  #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION				\
> > -CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags)	\
> > -	: Extensible(std::make_unique<Private>(this, camera3Buffer, flags)) \
> > +CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer,		\
> > +			   libcamera::PixelFormat pixelFormat,		\
> > +			   const libcamera::Size &size, int flags)	\
> > +	: Extensible(std::make_unique<Private>(this, camera3Buffer,	\
> > +					       pixelFormat, size,	\
> > +					       flags))			\
> >  {									\
> >  }									\
> >  CameraBuffer::~CameraBuffer()						\
> > diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> > index 61b44183..01909ec7 100644
> > --- a/src/android/camera_stream.cpp
> > +++ b/src/android/camera_stream.cpp
> > @@ -110,7 +110,9 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
> >  	 * \todo Buffer mapping and processing should be moved to a
> >  	 * separate thread.
> >  	 */
> > -	CameraBuffer dest(camera3Dest, PROT_READ | PROT_WRITE);
> > +	const StreamConfiguration &output = configuration();
> > +	CameraBuffer dest(camera3Dest, formats::MJPEG, output.size,
> > +			  PROT_READ | PROT_WRITE);
> >  	if (!dest.isValid()) {
> >  		LOG(HAL, Error) << "Failed to map android blob buffer";
> >  		return -EINVAL;
> > diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> > index e8783ff8..50732637 100644
> > --- a/src/android/mm/cros_camera_buffer.cpp
> > +++ b/src/android/mm/cros_camera_buffer.cpp
> > @@ -20,8 +20,9 @@ class CameraBuffer::Private : public Extensible::Private
> >  	LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> >
> >  public:
> > -	Private(CameraBuffer *cameraBuffer,
> > -		buffer_handle_t camera3Buffer, int flags);
> > +	Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > +		libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > +		int flags);
> >  	~Private();
> >
> >  	bool isValid() const { return valid_; }
> > @@ -46,6 +47,8 @@ private:
> >
> >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> >  			       buffer_handle_t camera3Buffer,
> > +			       [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> > +			       [[maybe_unused]] const libcamera::Size &size,
> >  			       [[maybe_unused]] int flags)
> >  	: handle_(camera3Buffer), numPlanes_(0), valid_(false),
> >  	  registered_(false)
> > diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> > index b3af194c..0bfdc2ba 100644
> > --- a/src/android/mm/generic_camera_buffer.cpp
> > +++ b/src/android/mm/generic_camera_buffer.cpp
> > @@ -12,6 +12,7 @@
> >
> >  #include <libcamera/base/log.h>
> >
> > +#include "libcamera/internal/formats.h"
> >  #include "libcamera/internal/mapped_framebuffer.h"
> >
> >  using namespace libcamera;
> > @@ -24,8 +25,9 @@ class CameraBuffer::Private : public Extensible::Private,
> >  	LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> >
> >  public:
> > -	Private(CameraBuffer *cameraBuffer,
> > -		buffer_handle_t camera3Buffer, int flags);
> > +	Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > +		libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > +		int flags);
> >  	~Private();
> >
> >  	unsigned int numPlanes() const;
> > @@ -33,35 +35,89 @@ public:
> >  	Span<uint8_t> plane(unsigned int plane);
> >
> >  	size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > +
> > +private:
> > +	/* \todo Remove planes_ when it will be added to MappedBuffer */
> > +	std::vector<Span<uint8_t>> planes_;
> >  };
> >
> >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > -			       buffer_handle_t camera3Buffer, int flags)
> > +			       buffer_handle_t camera3Buffer,
> > +			       libcamera::PixelFormat pixelFormat,
> > +			       const libcamera::Size &size, int flags)
> >  {
> > -	maps_.reserve(camera3Buffer->numFds);
> >  	error_ = 0;
> > -
> > +	/*
> > +	 * As Android doesn't offer an API to query buffer layouts, assume for
> > +	 * now that the buffer is backed by a single dmabuf, with planes being
> > +	 * stored contiguously.
> > +	 */
> > +	int fd = -1;
> >  	for (int i = 0; i < camera3Buffer->numFds; i++) {
>
> unsigned int i
>
> > -		if (camera3Buffer->data[i] == -1)
> > +		if (camera3Buffer->data[i] == -1 ||
> > +		    camera3Buffer->data[i] == fd) {
> >  			continue;
> > -
> > -		off_t length = lseek(camera3Buffer->data[i], 0, SEEK_END);
> > -		if (length < 0) {
> > -			error_ = -errno;
> > -			LOG(HAL, Error) << "Failed to query plane length";
> > -			break;
> >  		}
> >
> > -		void *address = mmap(nullptr, length, flags, MAP_SHARED,
> > -				     camera3Buffer->data[i], 0);
> > -		if (address == MAP_FAILED) {
> > -			error_ = -errno;
> > -			LOG(HAL, Error) << "Failed to mmap plane";
> > -			break;
> > -		}
> > +		if (fd != -1)
> > +			LOG(HAL, Fatal) << "Discontiguous planes are not supported";
>
> Do we just warn ? Or exit with error ? See the below question
>
> > +		fd = camera3Buffer->data[i];
>
> This assigns fd to the 'next' valid data[i].fd. I might have missed
> what is the policy here if we have more than one valid dmabuf fds.
>
> Currently you warn and use the last valid one. I would instead error out,
> or warn but use the first available one (even if that would result in
> undefined behaviour, or most probably an access to non valid memory when
> creating planes below).
>
> Do you have a use case for formats with planes allocated in different
> buffers that you need to support ? Or can we error out without causing
> regressions ?
>
> > +	}
>
> The loop is pretty convoluted. If I'm not mistaken what you want to
> verify is that
> 1) Either all data[i].fd are the same
> 2) All but the data[0].fd are -1
>
> Wouldn't it be nicer as
>
>         int fd = camera3Buffer->data[0].fd;
>         for (unsigned int i = 1; i < camera3Buffer->numFds; ++i) {
>                 if (camera3Buffer->data[i].fd != -1)

        I meant == -1
>                         continue;
>
>                 if (camera3Buffer->data[i].fd != fd)
>                         /* Here I would error out */
>         }
>         if (fd == -1) {
>                 /* No valid fds, error out */
>         }
>
> > +
> > +	if (fd != -1) {
>
> Shouldn't this be fd == -1 ? As in "no valid fd found ?"
> If I'm not mistaken checking for fd != -1 should fail all the times as
> at least one valid fd should be found. On which platform have you
> tested this patch ?
>
> > +		error_ = -EINVAL;
> > +		LOG(HAL, Error) << "No valid file descriptor";
> > +		return;
> > +	}
> >
> > -		maps_.emplace_back(static_cast<uint8_t *>(address),
> > -				   static_cast<size_t>(length));
> > +	const auto &info = libcamera::PixelFormatInfo::info(pixelFormat);
> > +	if (!info.isValid()) {
> > +		error_ = -EINVAL;
> > +		LOG(HAL, Error) << "Invalid pixel format: "
> > +				<< pixelFormat.toString();
> > +		return;
> > +	}
>
> We could check this at the very beginning of the function and avoid
> looping on fds if the format is invalid.
>
> > +
> > +	off_t bufferLength = lseek(fd, 0, SEEK_END);
> > +	if (bufferLength < 0) {
> > +		error_ = -errno;
> > +		LOG(HAL, Error) << "Failed to get buffer length";
> > +		return;
> > +	}
> > +
> > +	void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> > +	if (address == MAP_FAILED) {
> > +		error_ = -errno;
> > +		LOG(HAL, Error) << "Failed to mmap plane";
> > +		return;
> > +	}
> > +	maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> > +
> > +	const unsigned int numPlanes = info.numPlanes();
> > +	planes_.resize(numPlanes);
> > +	unsigned int offset = 0;
> > +	for (unsigned int i = 0; i < numPlanes; ++i) {
> > +		/*
> > +		 * \todo Remove if this plane size computation function is
> > +		 * added to PixelFormatInfo.
> > +		 */
> > +		const unsigned int vertSubSample = info.planes[i].verticalSubSampling;
> > +		const unsigned int stride = info.stride(size.width, i, 1u);
> > +		const unsigned int planeSize =
> > +			stride * ((size.height + vertSubSample - 1) / vertSubSample);
> > +
> > +		planes_[i] = libcamera::Span<uint8_t>(
> > +			static_cast<uint8_t *>(address) + offset, planeSize);
> > +
> > +		if (bufferLength < offset + planeSize) {
> > +			error_ = -EINVAL;
> > +			LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> > +					<< ", buffer length=" << bufferLength
> > +					<< ", offset=" << offset
> > +					<< ", size=" << planeSize;
> > +			return;
> > +		}
> > +		offset += planeSize;
> >  	}
> >  }
> >
> > @@ -71,15 +127,15 @@ CameraBuffer::Private::~Private()
> >
> >  unsigned int CameraBuffer::Private::numPlanes() const
> >  {
> > -	return maps_.size();
> > +	return planes_.size();
> >  }
> >
> >  Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> >  {
> > -	if (plane >= maps_.size())
> > +	if (plane >= planes_.size())
> >  		return {};
> >
> > -	return maps_[plane];
> > +	return planes_[plane];
> >  }
> >
> >  size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const
> > --
> > 2.33.0.rc2.250.ged5fa647cd-goog
> >

Hi Jacopo, thank you for reviewing.


On Wed, Aug 25, 2021 at 7:00 PM Jacopo Mondi <jacopo@jmondi.org> wrote:
>
> Ups,
>
> On Wed, Aug 25, 2021 at 10:35:07AM +0200, Jacopo Mondi wrote:
> > Hi Hiro,
> >
> > On Wed, Aug 25, 2021 at 01:44:08PM +0900, Hirokazu Honda wrote:
> > > buffer_hanlde_t doesn't provide sufficient info to map a buffer
> > > properly. cros::CameraBufferManager enables handling the buffer on
> > > ChromeOS, but no way is provided for other platforms.
> > >
> > > Therefore, we put the assumption that planes are in the same buffer
> > > and they are consecutive. This modifies the way of mapping in
> > > generic_camera_buffer with the assumption.
> > >
> > > Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
> > > ---
> > >  src/android/camera_buffer.h              |  14 ++-
> > >  src/android/camera_stream.cpp            |   4 +-
> > >  src/android/mm/cros_camera_buffer.cpp    |   7 +-
> > >  src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
> > >  4 files changed, 99 insertions(+), 30 deletions(-)
> > >
> > > diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
> > > index c4e3a9e7..87df2570 100644
> > > --- a/src/android/camera_buffer.h
> > > +++ b/src/android/camera_buffer.h
> > > @@ -11,13 +11,17 @@
> > >
> > >  #include <libcamera/base/class.h>
> > >  #include <libcamera/base/span.h>
> > > +#include <libcamera/geometry.h>
> > > +#include <libcamera/pixel_format.h>
> > >
> > >  class CameraBuffer final : public libcamera::Extensible
> > >  {
> > >     LIBCAMERA_DECLARE_PRIVATE()
> > >
> > >  public:
> > > -   CameraBuffer(buffer_handle_t camera3Buffer, int flags);
> > > +   CameraBuffer(buffer_handle_t camera3Buffer,
> > > +                libcamera::PixelFormat pixelFormat,
> > > +                const libcamera::Size &size, int flags);
> > >     ~CameraBuffer();
> > >
> > >     bool isValid() const;
> > > @@ -31,8 +35,12 @@ public:
> > >  };
> > >
> > >  #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION                                \
> > > -CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags)       \
> > > -   : Extensible(std::make_unique<Private>(this, camera3Buffer, flags)) \
> > > +CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer,          \
> > > +                      libcamera::PixelFormat pixelFormat,          \
> > > +                      const libcamera::Size &size, int flags)      \
> > > +   : Extensible(std::make_unique<Private>(this, camera3Buffer,     \
> > > +                                          pixelFormat, size,       \
> > > +                                          flags))                  \
> > >  {                                                                  \
> > >  }                                                                  \
> > >  CameraBuffer::~CameraBuffer()                                              \
> > > diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> > > index 61b44183..01909ec7 100644
> > > --- a/src/android/camera_stream.cpp
> > > +++ b/src/android/camera_stream.cpp
> > > @@ -110,7 +110,9 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
> > >      * \todo Buffer mapping and processing should be moved to a
> > >      * separate thread.
> > >      */
> > > -   CameraBuffer dest(camera3Dest, PROT_READ | PROT_WRITE);
> > > +   const StreamConfiguration &output = configuration();
> > > +   CameraBuffer dest(camera3Dest, formats::MJPEG, output.size,
> > > +                     PROT_READ | PROT_WRITE);
> > >     if (!dest.isValid()) {
> > >             LOG(HAL, Error) << "Failed to map android blob buffer";
> > >             return -EINVAL;
> > > diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> > > index e8783ff8..50732637 100644
> > > --- a/src/android/mm/cros_camera_buffer.cpp
> > > +++ b/src/android/mm/cros_camera_buffer.cpp
> > > @@ -20,8 +20,9 @@ class CameraBuffer::Private : public Extensible::Private
> > >     LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > >
> > >  public:
> > > -   Private(CameraBuffer *cameraBuffer,
> > > -           buffer_handle_t camera3Buffer, int flags);
> > > +   Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > +           libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > +           int flags);
> > >     ~Private();
> > >
> > >     bool isValid() const { return valid_; }
> > > @@ -46,6 +47,8 @@ private:
> > >
> > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > >                            buffer_handle_t camera3Buffer,
> > > +                          [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> > > +                          [[maybe_unused]] const libcamera::Size &size,
> > >                            [[maybe_unused]] int flags)
> > >     : handle_(camera3Buffer), numPlanes_(0), valid_(false),
> > >       registered_(false)
> > > diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> > > index b3af194c..0bfdc2ba 100644
> > > --- a/src/android/mm/generic_camera_buffer.cpp
> > > +++ b/src/android/mm/generic_camera_buffer.cpp
> > > @@ -12,6 +12,7 @@
> > >
> > >  #include <libcamera/base/log.h>
> > >
> > > +#include "libcamera/internal/formats.h"
> > >  #include "libcamera/internal/mapped_framebuffer.h"
> > >
> > >  using namespace libcamera;
> > > @@ -24,8 +25,9 @@ class CameraBuffer::Private : public Extensible::Private,
> > >     LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > >
> > >  public:
> > > -   Private(CameraBuffer *cameraBuffer,
> > > -           buffer_handle_t camera3Buffer, int flags);
> > > +   Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > +           libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > +           int flags);
> > >     ~Private();
> > >
> > >     unsigned int numPlanes() const;
> > > @@ -33,35 +35,89 @@ public:
> > >     Span<uint8_t> plane(unsigned int plane);
> > >
> > >     size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > > +
> > > +private:
> > > +   /* \todo Remove planes_ when it will be added to MappedBuffer */
> > > +   std::vector<Span<uint8_t>> planes_;
> > >  };
> > >
> > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > -                          buffer_handle_t camera3Buffer, int flags)
> > > +                          buffer_handle_t camera3Buffer,
> > > +                          libcamera::PixelFormat pixelFormat,
> > > +                          const libcamera::Size &size, int flags)
> > >  {
> > > -   maps_.reserve(camera3Buffer->numFds);
> > >     error_ = 0;
> > > -
> > > +   /*
> > > +    * As Android doesn't offer an API to query buffer layouts, assume for
> > > +    * now that the buffer is backed by a single dmabuf, with planes being
> > > +    * stored contiguously.
> > > +    */
> > > +   int fd = -1;
> > >     for (int i = 0; i < camera3Buffer->numFds; i++) {
> >
> > unsigned int i

The type of buffer_handle_t's numFds is int strangely. :-S
If I use unsigned int here, a compiler complains the comparison against numFds.

> >
> > > -           if (camera3Buffer->data[i] == -1)
> > > +           if (camera3Buffer->data[i] == -1 ||
> > > +               camera3Buffer->data[i] == fd) {
> > >                     continue;
> > > -
> > > -           off_t length = lseek(camera3Buffer->data[i], 0, SEEK_END);
> > > -           if (length < 0) {
> > > -                   error_ = -errno;
> > > -                   LOG(HAL, Error) << "Failed to query plane length";
> > > -                   break;
> > >             }
> > >
> > > -           void *address = mmap(nullptr, length, flags, MAP_SHARED,
> > > -                                camera3Buffer->data[i], 0);
> > > -           if (address == MAP_FAILED) {
> > > -                   error_ = -errno;
> > > -                   LOG(HAL, Error) << "Failed to mmap plane";
> > > -                   break;
> > > -           }
> > > +           if (fd != -1)
> > > +                   LOG(HAL, Fatal) << "Discontiguous planes are not supported";
> >
> > Do we just warn ? Or exit with error ? See the below question
> >
> > > +           fd = camera3Buffer->data[i];
> >
> > This assigns fd to the 'next' valid data[i].fd. I might have missed
> > what is the policy here if we have more than one valid dmabuf fds.
> >
> > Currently you warn and use the last valid one. I would instead error out,
> > or warn but use the first available one (even if that would result in
> > undefined behaviour, or most probably an access to non valid memory when
> > creating planes below).
> >
> > Do you have a use case for formats with planes allocated in different
> > buffers that you need to support ? Or can we error out without causing
> > regressions ?
> >

This is just from Laurent's comment.
I think no platform except ChromeOS has used libcamera Android HAL.
To catch something bad easily, we implement so.

> > > +   }
> >
> > The loop is pretty convoluted. If I'm not mistaken what you want to
> > verify is that
> > 1) Either all data[i].fd are the same
> > 2) All but the data[0].fd are -1
> >
> > Wouldn't it be nicer as
> >
> >         int fd = camera3Buffer->data[0].fd;
> >         for (unsigned int i = 1; i < camera3Buffer->numFds; ++i) {
> >                 if (camera3Buffer->data[i].fd != -1)
>
>         I meant == -1
> >                         continue;
> >
> >                 if (camera3Buffer->data[i].fd != fd)
> >                         /* Here I would error out */
> >         }
> >         if (fd == -1) {
> >                 /* No valid fds, error out */
> >         }
> >
> > > +
> > > +   if (fd != -1) {
> >
> > Shouldn't this be fd == -1 ? As in "no valid fd found ?"
> > If I'm not mistaken checking for fd != -1 should fail all the times as
> > at least one valid fd should be found. On which platform have you
> > tested this patch ?
> >

Thanks for catching this. I haven't tested this implementation as I am
testing on ChromeOS.
Is there any easy way of testing android HAL implementation on Linux?

-Hiro
> > > +           error_ = -EINVAL;
> > > +           LOG(HAL, Error) << "No valid file descriptor";
> > > +           return;
> > > +   }
> > >
> > > -           maps_.emplace_back(static_cast<uint8_t *>(address),
> > > -                              static_cast<size_t>(length));
> > > +   const auto &info = libcamera::PixelFormatInfo::info(pixelFormat);
> > > +   if (!info.isValid()) {
> > > +           error_ = -EINVAL;
> > > +           LOG(HAL, Error) << "Invalid pixel format: "
> > > +                           << pixelFormat.toString();
> > > +           return;
> > > +   }
> >
> > We could check this at the very beginning of the function and avoid
> > looping on fds if the format is invalid.
> >
> > > +
> > > +   off_t bufferLength = lseek(fd, 0, SEEK_END);
> > > +   if (bufferLength < 0) {
> > > +           error_ = -errno;
> > > +           LOG(HAL, Error) << "Failed to get buffer length";
> > > +           return;
> > > +   }
> > > +
> > > +   void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> > > +   if (address == MAP_FAILED) {
> > > +           error_ = -errno;
> > > +           LOG(HAL, Error) << "Failed to mmap plane";
> > > +           return;
> > > +   }
> > > +   maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> > > +
> > > +   const unsigned int numPlanes = info.numPlanes();
> > > +   planes_.resize(numPlanes);
> > > +   unsigned int offset = 0;
> > > +   for (unsigned int i = 0; i < numPlanes; ++i) {
> > > +           /*
> > > +            * \todo Remove if this plane size computation function is
> > > +            * added to PixelFormatInfo.
> > > +            */
> > > +           const unsigned int vertSubSample = info.planes[i].verticalSubSampling;
> > > +           const unsigned int stride = info.stride(size.width, i, 1u);
> > > +           const unsigned int planeSize =
> > > +                   stride * ((size.height + vertSubSample - 1) / vertSubSample);
> > > +
> > > +           planes_[i] = libcamera::Span<uint8_t>(
> > > +                   static_cast<uint8_t *>(address) + offset, planeSize);
> > > +
> > > +           if (bufferLength < offset + planeSize) {
> > > +                   error_ = -EINVAL;
> > > +                   LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> > > +                                   << ", buffer length=" << bufferLength
> > > +                                   << ", offset=" << offset
> > > +                                   << ", size=" << planeSize;
> > > +                   return;
> > > +           }
> > > +           offset += planeSize;
> > >     }
> > >  }
> > >
> > > @@ -71,15 +127,15 @@ CameraBuffer::Private::~Private()
> > >
> > >  unsigned int CameraBuffer::Private::numPlanes() const
> > >  {
> > > -   return maps_.size();
> > > +   return planes_.size();
> > >  }
> > >
> > >  Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> > >  {
> > > -   if (plane >= maps_.size())
> > > +   if (plane >= planes_.size())
> > >             return {};
> > >
> > > -   return maps_[plane];
> > > +   return planes_[plane];
> > >  }
> > >
> > >  size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const
> > > --
> > > 2.33.0.rc2.250.ged5fa647cd-goog
> > >

Hi Hiro,

On Wed, Aug 25, 2021 at 07:57:23PM +0900, Hirokazu Honda wrote:
> On Wed, Aug 25, 2021 at 7:00 PM Jacopo Mondi wrote:
> > On Wed, Aug 25, 2021 at 10:35:07AM +0200, Jacopo Mondi wrote:
> > > On Wed, Aug 25, 2021 at 01:44:08PM +0900, Hirokazu Honda wrote:
> > > > buffer_hanlde_t doesn't provide sufficient info to map a buffer

s/buffer_hanlde_t/buffer_handle_t/

> > > > properly. cros::CameraBufferManager enables handling the buffer on
> > > > ChromeOS, but no way is provided for other platforms.
> > > >
> > > > Therefore, we put the assumption that planes are in the same buffer
> > > > and they are consecutive. This modifies the way of mapping in
> > > > generic_camera_buffer with the assumption.
> > > >
> > > > Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
> > > > ---
> > > >  src/android/camera_buffer.h              |  14 ++-
> > > >  src/android/camera_stream.cpp            |   4 +-
> > > >  src/android/mm/cros_camera_buffer.cpp    |   7 +-
> > > >  src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
> > > >  4 files changed, 99 insertions(+), 30 deletions(-)
> > > >
> > > > diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
> > > > index c4e3a9e7..87df2570 100644
> > > > --- a/src/android/camera_buffer.h
> > > > +++ b/src/android/camera_buffer.h
> > > > @@ -11,13 +11,17 @@
> > > >
> > > >  #include <libcamera/base/class.h>
> > > >  #include <libcamera/base/span.h>
> > > > +#include <libcamera/geometry.h>
> > > > +#include <libcamera/pixel_format.h>
> > > >
> > > >  class CameraBuffer final : public libcamera::Extensible
> > > >  {
> > > >     LIBCAMERA_DECLARE_PRIVATE()
> > > >
> > > >  public:
> > > > -   CameraBuffer(buffer_handle_t camera3Buffer, int flags);
> > > > +   CameraBuffer(buffer_handle_t camera3Buffer,
> > > > +                libcamera::PixelFormat pixelFormat,
> > > > +                const libcamera::Size &size, int flags);
> > > >     ~CameraBuffer();
> > > >
> > > >     bool isValid() const;
> > > > @@ -31,8 +35,12 @@ public:
> > > >  };
> > > >
> > > >  #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION                                \
> > > > -CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags)       \
> > > > -   : Extensible(std::make_unique<Private>(this, camera3Buffer, flags)) \
> > > > +CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer,          \
> > > > +                      libcamera::PixelFormat pixelFormat,          \
> > > > +                      const libcamera::Size &size, int flags)      \
> > > > +   : Extensible(std::make_unique<Private>(this, camera3Buffer,     \
> > > > +                                          pixelFormat, size,       \
> > > > +                                          flags))                  \
> > > >  {                                                                  \
> > > >  }                                                                  \
> > > >  CameraBuffer::~CameraBuffer()                                              \
> > > > diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> > > > index 61b44183..01909ec7 100644
> > > > --- a/src/android/camera_stream.cpp
> > > > +++ b/src/android/camera_stream.cpp
> > > > @@ -110,7 +110,9 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
> > > >      * \todo Buffer mapping and processing should be moved to a
> > > >      * separate thread.
> > > >      */
> > > > -   CameraBuffer dest(camera3Dest, PROT_READ | PROT_WRITE);
> > > > +   const StreamConfiguration &output = configuration();
> > > > +   CameraBuffer dest(camera3Dest, formats::MJPEG, output.size,
> > > > +                     PROT_READ | PROT_WRITE);
> > > >     if (!dest.isValid()) {
> > > >             LOG(HAL, Error) << "Failed to map android blob buffer";
> > > >             return -EINVAL;
> > > > diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> > > > index e8783ff8..50732637 100644
> > > > --- a/src/android/mm/cros_camera_buffer.cpp
> > > > +++ b/src/android/mm/cros_camera_buffer.cpp
> > > > @@ -20,8 +20,9 @@ class CameraBuffer::Private : public Extensible::Private
> > > >     LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > > >
> > > >  public:
> > > > -   Private(CameraBuffer *cameraBuffer,
> > > > -           buffer_handle_t camera3Buffer, int flags);
> > > > +   Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > > +           libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > > +           int flags);
> > > >     ~Private();
> > > >
> > > >     bool isValid() const { return valid_; }
> > > > @@ -46,6 +47,8 @@ private:
> > > >
> > > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > >                            buffer_handle_t camera3Buffer,
> > > > +                          [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> > > > +                          [[maybe_unused]] const libcamera::Size &size,
> > > >                            [[maybe_unused]] int flags)
> > > >     : handle_(camera3Buffer), numPlanes_(0), valid_(false),
> > > >       registered_(false)
> > > > diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> > > > index b3af194c..0bfdc2ba 100644
> > > > --- a/src/android/mm/generic_camera_buffer.cpp
> > > > +++ b/src/android/mm/generic_camera_buffer.cpp
> > > > @@ -12,6 +12,7 @@
> > > >
> > > >  #include <libcamera/base/log.h>
> > > >
> > > > +#include "libcamera/internal/formats.h"
> > > >  #include "libcamera/internal/mapped_framebuffer.h"
> > > >
> > > >  using namespace libcamera;
> > > > @@ -24,8 +25,9 @@ class CameraBuffer::Private : public Extensible::Private,
> > > >     LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > > >
> > > >  public:
> > > > -   Private(CameraBuffer *cameraBuffer,
> > > > -           buffer_handle_t camera3Buffer, int flags);
> > > > +   Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > > +           libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > > +           int flags);
> > > >     ~Private();
> > > >
> > > >     unsigned int numPlanes() const;
> > > > @@ -33,35 +35,89 @@ public:
> > > >     Span<uint8_t> plane(unsigned int plane);
> > > >
> > > >     size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > > > +
> > > > +private:
> > > > +   /* \todo Remove planes_ when it will be added to MappedBuffer */
> > > > +   std::vector<Span<uint8_t>> planes_;
> > > >  };
> > > >
> > > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > > -                          buffer_handle_t camera3Buffer, int flags)
> > > > +                          buffer_handle_t camera3Buffer,
> > > > +                          libcamera::PixelFormat pixelFormat,
> > > > +                          const libcamera::Size &size, int flags)
> > > >  {
> > > > -   maps_.reserve(camera3Buffer->numFds);
> > > >     error_ = 0;
> > > > -
> > > > +   /*
> > > > +    * As Android doesn't offer an API to query buffer layouts, assume for
> > > > +    * now that the buffer is backed by a single dmabuf, with planes being
> > > > +    * stored contiguously.
> > > > +    */
> > > > +   int fd = -1;
> > > >     for (int i = 0; i < camera3Buffer->numFds; i++) {
> > >
> > > unsigned int i
> 
> The type of buffer_handle_t's numFds is int strangely. :-S
> If I use unsigned int here, a compiler complains the comparison against numFds.

Agreed, we have to use a signed int to avoid signed vs. unsigned
comparison warnings.

> > > > -           if (camera3Buffer->data[i] == -1)
> > > > +           if (camera3Buffer->data[i] == -1 ||
> > > > +               camera3Buffer->data[i] == fd) {
> > > >                     continue;
> > > > -
> > > > -           off_t length = lseek(camera3Buffer->data[i], 0, SEEK_END);
> > > > -           if (length < 0) {
> > > > -                   error_ = -errno;
> > > > -                   LOG(HAL, Error) << "Failed to query plane length";
> > > > -                   break;
> > > >             }

No need for curly braces around the continue.

> > > >
> > > > -           void *address = mmap(nullptr, length, flags, MAP_SHARED,
> > > > -                                camera3Buffer->data[i], 0);
> > > > -           if (address == MAP_FAILED) {
> > > > -                   error_ = -errno;
> > > > -                   LOG(HAL, Error) << "Failed to mmap plane";
> > > > -                   break;
> > > > -           }
> > > > +           if (fd != -1)
> > > > +                   LOG(HAL, Fatal) << "Discontiguous planes are not supported";
> > >
> > > Do we just warn ? Or exit with error ? See the below question

We could indeed error out instead of aborting.

		if (fd != -1) {
			error_ = -EINVAL;
			LOG(HAL, Error) << "Discontiguous planes are not supported";
			return;
		}

> > >
> > > > +           fd = camera3Buffer->data[i];
> > >
> > > This assigns fd to the 'next' valid data[i].fd. I might have missed
> > > what is the policy here if we have more than one valid dmabuf fds.
> > >
> > > Currently you warn and use the last valid one. I would instead error out,
> > > or warn but use the first available one (even if that would result in
> > > undefined behaviour, or most probably an access to non valid memory when
> > > creating planes below).
> > >
> > > Do you have a use case for formats with planes allocated in different
> > > buffers that you need to support ? Or can we error out without causing
> > > regressions ?
> 
> This is just from Laurent's comment.
> I think no platform except ChromeOS has used libcamera Android HAL.
> To catch something bad easily, we implement so.
>
> > > > +   }
> > >
> > > The loop is pretty convoluted. If I'm not mistaken what you want to
> > > verify is that
> > > 1) Either all data[i].fd are the same
> > > 2) All but the data[0].fd are -1
> > >
> > > Wouldn't it be nicer as
> > >
> > >         int fd = camera3Buffer->data[0].fd;
> > >         for (unsigned int i = 1; i < camera3Buffer->numFds; ++i) {
> > >                 if (camera3Buffer->data[i].fd != -1)
> >
> >         I meant == -1
> > >                         continue;
> > >
> > >                 if (camera3Buffer->data[i].fd != fd)
> > >                         /* Here I would error out */
> > >         }
> > >         if (fd == -1) {
> > >                 /* No valid fds, error out */
> > >         }

We could do this too, I like my version, but if Hiro you think this is
better, that's fine with me too.

> > > > +
> > > > +   if (fd != -1) {
> > >
> > > Shouldn't this be fd == -1 ? As in "no valid fd found ?"
> > > If I'm not mistaken checking for fd != -1 should fail all the times as
> > > at least one valid fd should be found. On which platform have you
> > > tested this patch ?
> 
> Thanks for catching this. I haven't tested this implementation as I am
> testing on ChromeOS.
> Is there any easy way of testing android HAL implementation on Linux?

Not easily yet, but I'm working on this.

> > > > +           error_ = -EINVAL;
> > > > +           LOG(HAL, Error) << "No valid file descriptor";
> > > > +           return;
> > > > +   }
> > > >
> > > > -           maps_.emplace_back(static_cast<uint8_t *>(address),
> > > > -                              static_cast<size_t>(length));
> > > > +   const auto &info = libcamera::PixelFormatInfo::info(pixelFormat);
> > > > +   if (!info.isValid()) {
> > > > +           error_ = -EINVAL;
> > > > +           LOG(HAL, Error) << "Invalid pixel format: "
> > > > +                           << pixelFormat.toString();
> > > > +           return;
> > > > +   }
> > >
> > > We could check this at the very beginning of the function and avoid
> > > looping on fds if the format is invalid.

I don't mind either way. This shouldn't happen in any case, so there's
no performance impact, I'd thus favour what you think produces the
cleanest code.

> > > > +
> > > > +   off_t bufferLength = lseek(fd, 0, SEEK_END);
> > > > +   if (bufferLength < 0) {
> > > > +           error_ = -errno;
> > > > +           LOG(HAL, Error) << "Failed to get buffer length";
> > > > +           return;
> > > > +   }
> > > > +
> > > > +   void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> > > > +   if (address == MAP_FAILED) {
> > > > +           error_ = -errno;
> > > > +           LOG(HAL, Error) << "Failed to mmap plane";
> > > > +           return;
> > > > +   }
> > > > +   maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> > > > +
> > > > +   const unsigned int numPlanes = info.numPlanes();
> > > > +   planes_.resize(numPlanes);
> > > > +   unsigned int offset = 0;
> > > > +   for (unsigned int i = 0; i < numPlanes; ++i) {
> > > > +           /*
> > > > +            * \todo Remove if this plane size computation function is
> > > > +            * added to PixelFormatInfo.
> > > > +            */
> > > > +           const unsigned int vertSubSample = info.planes[i].verticalSubSampling;
> > > > +           const unsigned int stride = info.stride(size.width, i, 1u);
> > > > +           const unsigned int planeSize =
> > > > +                   stride * ((size.height + vertSubSample - 1) / vertSubSample);
> > > > +
> > > > +           planes_[i] = libcamera::Span<uint8_t>(
> > > > +                   static_cast<uint8_t *>(address) + offset, planeSize);
> > > > +
> > > > +           if (bufferLength < offset + planeSize) {
> > > > +                   error_ = -EINVAL;
> > > > +                   LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> > > > +                                   << ", buffer length=" << bufferLength
> > > > +                                   << ", offset=" << offset
> > > > +                                   << ", size=" << planeSize;
> > > > +                   return;
> > > > +           }
> > > > +           offset += planeSize;
> > > >     }
> > > >  }
> > > >
> > > > @@ -71,15 +127,15 @@ CameraBuffer::Private::~Private()
> > > >
> > > >  unsigned int CameraBuffer::Private::numPlanes() const
> > > >  {
> > > > -   return maps_.size();
> > > > +   return planes_.size();
> > > >  }
> > > >
> > > >  Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> > > >  {
> > > > -   if (plane >= maps_.size())
> > > > +   if (plane >= planes_.size())
> > > >             return {};
> > > >
> > > > -   return maps_[plane];
> > > > +   return planes_[plane];
> > > >  }
> > > >
> > > >  size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const

On Wed, Aug 25, 2021 at 5:34 PM Jacopo Mondi <jacopo@jmondi.org> wrote:
>
> Hi Hiro,
>
> On Wed, Aug 25, 2021 at 01:44:08PM +0900, Hirokazu Honda wrote:
> > buffer_hanlde_t doesn't provide sufficient info to map a buffer
> > properly. cros::CameraBufferManager enables handling the buffer on
> > ChromeOS, but no way is provided for other platforms.
> >
> > Therefore, we put the assumption that planes are in the same buffer
> > and they are consecutive. This modifies the way of mapping in
> > generic_camera_buffer with the assumption.
> >
> > Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
> > ---
> >  src/android/camera_buffer.h              |  14 ++-
> >  src/android/camera_stream.cpp            |   4 +-
> >  src/android/mm/cros_camera_buffer.cpp    |   7 +-
> >  src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
> >  4 files changed, 99 insertions(+), 30 deletions(-)
> >
> > diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
> > index c4e3a9e7..87df2570 100644
> > --- a/src/android/camera_buffer.h
> > +++ b/src/android/camera_buffer.h
> > @@ -11,13 +11,17 @@
> >
> >  #include <libcamera/base/class.h>
> >  #include <libcamera/base/span.h>
> > +#include <libcamera/geometry.h>
> > +#include <libcamera/pixel_format.h>
> >
> >  class CameraBuffer final : public libcamera::Extensible
> >  {
> >       LIBCAMERA_DECLARE_PRIVATE()
> >
> >  public:
> > -     CameraBuffer(buffer_handle_t camera3Buffer, int flags);
> > +     CameraBuffer(buffer_handle_t camera3Buffer,
> > +                  libcamera::PixelFormat pixelFormat,
> > +                  const libcamera::Size &size, int flags);
> >       ~CameraBuffer();
> >
> >       bool isValid() const;
> > @@ -31,8 +35,12 @@ public:
> >  };
> >
> >  #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION                          \
> > -CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags) \
> > -     : Extensible(std::make_unique<Private>(this, camera3Buffer, flags)) \
> > +CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer,            \
> > +                        libcamera::PixelFormat pixelFormat,          \
> > +                        const libcamera::Size &size, int flags)      \
> > +     : Extensible(std::make_unique<Private>(this, camera3Buffer,     \
> > +                                            pixelFormat, size,       \
> > +                                            flags))                  \
> >  {                                                                    \
> >  }                                                                    \
> >  CameraBuffer::~CameraBuffer()                                                \
> > diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> > index 61b44183..01909ec7 100644
> > --- a/src/android/camera_stream.cpp
> > +++ b/src/android/camera_stream.cpp
> > @@ -110,7 +110,9 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
> >        * \todo Buffer mapping and processing should be moved to a
> >        * separate thread.
> >        */
> > -     CameraBuffer dest(camera3Dest, PROT_READ | PROT_WRITE);
> > +     const StreamConfiguration &output = configuration();
> > +     CameraBuffer dest(camera3Dest, formats::MJPEG, output.size,
> > +                       PROT_READ | PROT_WRITE);
> >       if (!dest.isValid()) {
> >               LOG(HAL, Error) << "Failed to map android blob buffer";
> >               return -EINVAL;
> > diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> > index e8783ff8..50732637 100644
> > --- a/src/android/mm/cros_camera_buffer.cpp
> > +++ b/src/android/mm/cros_camera_buffer.cpp
> > @@ -20,8 +20,9 @@ class CameraBuffer::Private : public Extensible::Private
> >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> >
> >  public:
> > -     Private(CameraBuffer *cameraBuffer,
> > -             buffer_handle_t camera3Buffer, int flags);
> > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > +             int flags);
> >       ~Private();
> >
> >       bool isValid() const { return valid_; }
> > @@ -46,6 +47,8 @@ private:
> >
> >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> >                              buffer_handle_t camera3Buffer,
> > +                            [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> > +                            [[maybe_unused]] const libcamera::Size &size,
> >                              [[maybe_unused]] int flags)
> >       : handle_(camera3Buffer), numPlanes_(0), valid_(false),
> >         registered_(false)
> > diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> > index b3af194c..0bfdc2ba 100644
> > --- a/src/android/mm/generic_camera_buffer.cpp
> > +++ b/src/android/mm/generic_camera_buffer.cpp
> > @@ -12,6 +12,7 @@
> >
> >  #include <libcamera/base/log.h>
> >
> > +#include "libcamera/internal/formats.h"
> >  #include "libcamera/internal/mapped_framebuffer.h"
> >
> >  using namespace libcamera;
> > @@ -24,8 +25,9 @@ class CameraBuffer::Private : public Extensible::Private,
> >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> >
> >  public:
> > -     Private(CameraBuffer *cameraBuffer,
> > -             buffer_handle_t camera3Buffer, int flags);
> > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > +             int flags);
> >       ~Private();
> >
> >       unsigned int numPlanes() const;
> > @@ -33,35 +35,89 @@ public:
> >       Span<uint8_t> plane(unsigned int plane);
> >
> >       size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > +
> > +private:
> > +     /* \todo Remove planes_ when it will be added to MappedBuffer */
> > +     std::vector<Span<uint8_t>> planes_;
> >  };
> >
> >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > -                            buffer_handle_t camera3Buffer, int flags)
> > +                            buffer_handle_t camera3Buffer,
> > +                            libcamera::PixelFormat pixelFormat,
> > +                            const libcamera::Size &size, int flags)
> >  {
> > -     maps_.reserve(camera3Buffer->numFds);
> >       error_ = 0;
> > -
> > +     /*
> > +      * As Android doesn't offer an API to query buffer layouts, assume for
> > +      * now that the buffer is backed by a single dmabuf, with planes being
> > +      * stored contiguously.
> > +      */
> > +     int fd = -1;
> >       for (int i = 0; i < camera3Buffer->numFds; i++) {
>
> unsigned int i
>
> > -             if (camera3Buffer->data[i] == -1)
> > +             if (camera3Buffer->data[i] == -1 ||
> > +                 camera3Buffer->data[i] == fd) {
> >                       continue;
> > -
> > -             off_t length = lseek(camera3Buffer->data[i], 0, SEEK_END);
> > -             if (length < 0) {
> > -                     error_ = -errno;
> > -                     LOG(HAL, Error) << "Failed to query plane length";
> > -                     break;
> >               }
> >
> > -             void *address = mmap(nullptr, length, flags, MAP_SHARED,
> > -                                  camera3Buffer->data[i], 0);
> > -             if (address == MAP_FAILED) {
> > -                     error_ = -errno;
> > -                     LOG(HAL, Error) << "Failed to mmap plane";
> > -                     break;
> > -             }
> > +             if (fd != -1)
> > +                     LOG(HAL, Fatal) << "Discontiguous planes are not supported";
>
> Do we just warn ? Or exit with error ? See the below question
>
> > +             fd = camera3Buffer->data[i];
>
> This assigns fd to the 'next' valid data[i].fd. I might have missed
> what is the policy here if we have more than one valid dmabuf fds.
>
> Currently you warn and use the last valid one. I would instead error out,
> or warn but use the first available one (even if that would result in
> undefined behaviour, or most probably an access to non valid memory when
> creating planes below).
>
> Do you have a use case for formats with planes allocated in different
> buffers that you need to support ? Or can we error out without causing
> regressions ?
>
> > +     }
>
> The loop is pretty convoluted. If I'm not mistaken what you want to
> verify is that
> 1) Either all data[i].fd are the same

This is actually not something that would happen in practice, because
the handles are passed via Binder and even if the source puts the same
FD for all the planes, the receiver would see all different FDs,
because Binder would create a new FD for each array element.

> 2) All but the data[0].fd are -1
>
> Wouldn't it be nicer as
>
>         int fd = camera3Buffer->data[0].fd;
>         for (unsigned int i = 1; i < camera3Buffer->numFds; ++i) {
>                 if (camera3Buffer->data[i].fd != -1)
>                         continue;
>
>                 if (camera3Buffer->data[i].fd != fd)
>                         /* Here I would error out */
>         }
>         if (fd == -1) {
>                 /* No valid fds, error out */
>         }
>
> > +
> > +     if (fd != -1) {
>
> Shouldn't this be fd == -1 ? As in "no valid fd found ?"
> If I'm not mistaken checking for fd != -1 should fail all the times as
> at least one valid fd should be found. On which platform have you
> tested this patch ?
>
> > +             error_ = -EINVAL;
> > +             LOG(HAL, Error) << "No valid file descriptor";
> > +             return;
> > +     }
> >
> > -             maps_.emplace_back(static_cast<uint8_t *>(address),
> > -                                static_cast<size_t>(length));
> > +     const auto &info = libcamera::PixelFormatInfo::info(pixelFormat);
> > +     if (!info.isValid()) {
> > +             error_ = -EINVAL;
> > +             LOG(HAL, Error) << "Invalid pixel format: "
> > +                             << pixelFormat.toString();
> > +             return;
> > +     }
>
> We could check this at the very beginning of the function and avoid
> looping on fds if the format is invalid.
>
> > +
> > +     off_t bufferLength = lseek(fd, 0, SEEK_END);
> > +     if (bufferLength < 0) {
> > +             error_ = -errno;
> > +             LOG(HAL, Error) << "Failed to get buffer length";
> > +             return;
> > +     }
> > +
> > +     void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> > +     if (address == MAP_FAILED) {
> > +             error_ = -errno;
> > +             LOG(HAL, Error) << "Failed to mmap plane";
> > +             return;
> > +     }
> > +     maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> > +
> > +     const unsigned int numPlanes = info.numPlanes();
> > +     planes_.resize(numPlanes);
> > +     unsigned int offset = 0;
> > +     for (unsigned int i = 0; i < numPlanes; ++i) {
> > +             /*
> > +              * \todo Remove if this plane size computation function is
> > +              * added to PixelFormatInfo.
> > +              */
> > +             const unsigned int vertSubSample = info.planes[i].verticalSubSampling;
> > +             const unsigned int stride = info.stride(size.width, i, 1u);
> > +             const unsigned int planeSize =
> > +                     stride * ((size.height + vertSubSample - 1) / vertSubSample);
> > +
> > +             planes_[i] = libcamera::Span<uint8_t>(
> > +                     static_cast<uint8_t *>(address) + offset, planeSize);
> > +
> > +             if (bufferLength < offset + planeSize) {
> > +                     error_ = -EINVAL;
> > +                     LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> > +                                     << ", buffer length=" << bufferLength
> > +                                     << ", offset=" << offset
> > +                                     << ", size=" << planeSize;
> > +                     return;
> > +             }
> > +             offset += planeSize;
> >       }
> >  }
> >
> > @@ -71,15 +127,15 @@ CameraBuffer::Private::~Private()
> >
> >  unsigned int CameraBuffer::Private::numPlanes() const
> >  {
> > -     return maps_.size();
> > +     return planes_.size();
> >  }
> >
> >  Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> >  {
> > -     if (plane >= maps_.size())
> > +     if (plane >= planes_.size())
> >               return {};
> >
> > -     return maps_[plane];
> > +     return planes_[plane];
> >  }
> >
> >  size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const
> > --
> > 2.33.0.rc2.250.ged5fa647cd-goog
> >

Hi Tomasz,

On Fri, Aug 27, 2021 at 07:08:30PM +0900, Tomasz Figa wrote:
> On Wed, Aug 25, 2021 at 5:34 PM Jacopo Mondi wrote:
> > On Wed, Aug 25, 2021 at 01:44:08PM +0900, Hirokazu Honda wrote:
> > > buffer_hanlde_t doesn't provide sufficient info to map a buffer
> > > properly. cros::CameraBufferManager enables handling the buffer on
> > > ChromeOS, but no way is provided for other platforms.
> > >
> > > Therefore, we put the assumption that planes are in the same buffer
> > > and they are consecutive. This modifies the way of mapping in
> > > generic_camera_buffer with the assumption.
> > >
> > > Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
> > > ---
> > >  src/android/camera_buffer.h              |  14 ++-
> > >  src/android/camera_stream.cpp            |   4 +-
> > >  src/android/mm/cros_camera_buffer.cpp    |   7 +-
> > >  src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
> > >  4 files changed, 99 insertions(+), 30 deletions(-)
> > >
> > > diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
> > > index c4e3a9e7..87df2570 100644
> > > --- a/src/android/camera_buffer.h
> > > +++ b/src/android/camera_buffer.h
> > > @@ -11,13 +11,17 @@
> > >
> > >  #include <libcamera/base/class.h>
> > >  #include <libcamera/base/span.h>
> > > +#include <libcamera/geometry.h>
> > > +#include <libcamera/pixel_format.h>
> > >
> > >  class CameraBuffer final : public libcamera::Extensible
> > >  {
> > >       LIBCAMERA_DECLARE_PRIVATE()
> > >
> > >  public:
> > > -     CameraBuffer(buffer_handle_t camera3Buffer, int flags);
> > > +     CameraBuffer(buffer_handle_t camera3Buffer,
> > > +                  libcamera::PixelFormat pixelFormat,
> > > +                  const libcamera::Size &size, int flags);
> > >       ~CameraBuffer();
> > >
> > >       bool isValid() const;
> > > @@ -31,8 +35,12 @@ public:
> > >  };
> > >
> > >  #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION                          \
> > > -CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags) \
> > > -     : Extensible(std::make_unique<Private>(this, camera3Buffer, flags)) \
> > > +CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer,            \
> > > +                        libcamera::PixelFormat pixelFormat,          \
> > > +                        const libcamera::Size &size, int flags)      \
> > > +     : Extensible(std::make_unique<Private>(this, camera3Buffer,     \
> > > +                                            pixelFormat, size,       \
> > > +                                            flags))                  \
> > >  {                                                                    \
> > >  }                                                                    \
> > >  CameraBuffer::~CameraBuffer()                                                \
> > > diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> > > index 61b44183..01909ec7 100644
> > > --- a/src/android/camera_stream.cpp
> > > +++ b/src/android/camera_stream.cpp
> > > @@ -110,7 +110,9 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
> > >        * \todo Buffer mapping and processing should be moved to a
> > >        * separate thread.
> > >        */
> > > -     CameraBuffer dest(camera3Dest, PROT_READ | PROT_WRITE);
> > > +     const StreamConfiguration &output = configuration();
> > > +     CameraBuffer dest(camera3Dest, formats::MJPEG, output.size,
> > > +                       PROT_READ | PROT_WRITE);
> > >       if (!dest.isValid()) {
> > >               LOG(HAL, Error) << "Failed to map android blob buffer";
> > >               return -EINVAL;
> > > diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> > > index e8783ff8..50732637 100644
> > > --- a/src/android/mm/cros_camera_buffer.cpp
> > > +++ b/src/android/mm/cros_camera_buffer.cpp
> > > @@ -20,8 +20,9 @@ class CameraBuffer::Private : public Extensible::Private
> > >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > >
> > >  public:
> > > -     Private(CameraBuffer *cameraBuffer,
> > > -             buffer_handle_t camera3Buffer, int flags);
> > > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > +             int flags);
> > >       ~Private();
> > >
> > >       bool isValid() const { return valid_; }
> > > @@ -46,6 +47,8 @@ private:
> > >
> > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > >                              buffer_handle_t camera3Buffer,
> > > +                            [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> > > +                            [[maybe_unused]] const libcamera::Size &size,
> > >                              [[maybe_unused]] int flags)
> > >       : handle_(camera3Buffer), numPlanes_(0), valid_(false),
> > >         registered_(false)
> > > diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> > > index b3af194c..0bfdc2ba 100644
> > > --- a/src/android/mm/generic_camera_buffer.cpp
> > > +++ b/src/android/mm/generic_camera_buffer.cpp
> > > @@ -12,6 +12,7 @@
> > >
> > >  #include <libcamera/base/log.h>
> > >
> > > +#include "libcamera/internal/formats.h"
> > >  #include "libcamera/internal/mapped_framebuffer.h"
> > >
> > >  using namespace libcamera;
> > > @@ -24,8 +25,9 @@ class CameraBuffer::Private : public Extensible::Private,
> > >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > >
> > >  public:
> > > -     Private(CameraBuffer *cameraBuffer,
> > > -             buffer_handle_t camera3Buffer, int flags);
> > > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > +             int flags);
> > >       ~Private();
> > >
> > >       unsigned int numPlanes() const;
> > > @@ -33,35 +35,89 @@ public:
> > >       Span<uint8_t> plane(unsigned int plane);
> > >
> > >       size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > > +
> > > +private:
> > > +     /* \todo Remove planes_ when it will be added to MappedBuffer */
> > > +     std::vector<Span<uint8_t>> planes_;
> > >  };
> > >
> > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > -                            buffer_handle_t camera3Buffer, int flags)
> > > +                            buffer_handle_t camera3Buffer,
> > > +                            libcamera::PixelFormat pixelFormat,
> > > +                            const libcamera::Size &size, int flags)
> > >  {
> > > -     maps_.reserve(camera3Buffer->numFds);
> > >       error_ = 0;
> > > -
> > > +     /*
> > > +      * As Android doesn't offer an API to query buffer layouts, assume for
> > > +      * now that the buffer is backed by a single dmabuf, with planes being
> > > +      * stored contiguously.
> > > +      */
> > > +     int fd = -1;
> > >       for (int i = 0; i < camera3Buffer->numFds; i++) {
> >
> > unsigned int i
> >
> > > -             if (camera3Buffer->data[i] == -1)
> > > +             if (camera3Buffer->data[i] == -1 ||
> > > +                 camera3Buffer->data[i] == fd) {
> > >                       continue;
> > > -
> > > -             off_t length = lseek(camera3Buffer->data[i], 0, SEEK_END);
> > > -             if (length < 0) {
> > > -                     error_ = -errno;
> > > -                     LOG(HAL, Error) << "Failed to query plane length";
> > > -                     break;
> > >               }
> > >
> > > -             void *address = mmap(nullptr, length, flags, MAP_SHARED,
> > > -                                  camera3Buffer->data[i], 0);
> > > -             if (address == MAP_FAILED) {
> > > -                     error_ = -errno;
> > > -                     LOG(HAL, Error) << "Failed to mmap plane";
> > > -                     break;
> > > -             }
> > > +             if (fd != -1)
> > > +                     LOG(HAL, Fatal) << "Discontiguous planes are not supported";
> >
> > Do we just warn ? Or exit with error ? See the below question
> >
> > > +             fd = camera3Buffer->data[i];
> >
> > This assigns fd to the 'next' valid data[i].fd. I might have missed
> > what is the policy here if we have more than one valid dmabuf fds.
> >
> > Currently you warn and use the last valid one. I would instead error out,
> > or warn but use the first available one (even if that would result in
> > undefined behaviour, or most probably an access to non valid memory when
> > creating planes below).
> >
> > Do you have a use case for formats with planes allocated in different
> > buffers that you need to support ? Or can we error out without causing
> > regressions ?
> >
> > > +     }
> >
> > The loop is pretty convoluted. If I'm not mistaken what you want to
> > verify is that
> > 1) Either all data[i].fd are the same
> 
> This is actually not something that would happen in practice, because
> the handles are passed via Binder and even if the source puts the same
> FD for all the planes, the receiver would see all different FDs,
> because Binder would create a new FD for each array element.

Sounds like there's room for improvement in binder then. Nevertheless,
we certainly want to support the case where the fds will be different
but all refer to the same dmabuf. The main blocker for this is the
ability to actually test it on Android, which I'm working on.

> > 2) All but the data[0].fd are -1
> >
> > Wouldn't it be nicer as
> >
> >         int fd = camera3Buffer->data[0].fd;
> >         for (unsigned int i = 1; i < camera3Buffer->numFds; ++i) {
> >                 if (camera3Buffer->data[i].fd != -1)
> >                         continue;
> >
> >                 if (camera3Buffer->data[i].fd != fd)
> >                         /* Here I would error out */
> >         }
> >         if (fd == -1) {
> >                 /* No valid fds, error out */
> >         }
> >
> > > +
> > > +     if (fd != -1) {
> >
> > Shouldn't this be fd == -1 ? As in "no valid fd found ?"
> > If I'm not mistaken checking for fd != -1 should fail all the times as
> > at least one valid fd should be found. On which platform have you
> > tested this patch ?
> >
> > > +             error_ = -EINVAL;
> > > +             LOG(HAL, Error) << "No valid file descriptor";
> > > +             return;
> > > +     }
> > >
> > > -             maps_.emplace_back(static_cast<uint8_t *>(address),
> > > -                                static_cast<size_t>(length));
> > > +     const auto &info = libcamera::PixelFormatInfo::info(pixelFormat);
> > > +     if (!info.isValid()) {
> > > +             error_ = -EINVAL;
> > > +             LOG(HAL, Error) << "Invalid pixel format: "
> > > +                             << pixelFormat.toString();
> > > +             return;
> > > +     }
> >
> > We could check this at the very beginning of the function and avoid
> > looping on fds if the format is invalid.
> >
> > > +
> > > +     off_t bufferLength = lseek(fd, 0, SEEK_END);
> > > +     if (bufferLength < 0) {
> > > +             error_ = -errno;
> > > +             LOG(HAL, Error) << "Failed to get buffer length";
> > > +             return;
> > > +     }
> > > +
> > > +     void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> > > +     if (address == MAP_FAILED) {
> > > +             error_ = -errno;
> > > +             LOG(HAL, Error) << "Failed to mmap plane";
> > > +             return;
> > > +     }
> > > +     maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> > > +
> > > +     const unsigned int numPlanes = info.numPlanes();
> > > +     planes_.resize(numPlanes);
> > > +     unsigned int offset = 0;
> > > +     for (unsigned int i = 0; i < numPlanes; ++i) {
> > > +             /*
> > > +              * \todo Remove if this plane size computation function is
> > > +              * added to PixelFormatInfo.
> > > +              */
> > > +             const unsigned int vertSubSample = info.planes[i].verticalSubSampling;
> > > +             const unsigned int stride = info.stride(size.width, i, 1u);
> > > +             const unsigned int planeSize =
> > > +                     stride * ((size.height + vertSubSample - 1) / vertSubSample);
> > > +
> > > +             planes_[i] = libcamera::Span<uint8_t>(
> > > +                     static_cast<uint8_t *>(address) + offset, planeSize);
> > > +
> > > +             if (bufferLength < offset + planeSize) {
> > > +                     error_ = -EINVAL;
> > > +                     LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> > > +                                     << ", buffer length=" << bufferLength
> > > +                                     << ", offset=" << offset
> > > +                                     << ", size=" << planeSize;
> > > +                     return;
> > > +             }
> > > +             offset += planeSize;
> > >       }
> > >  }
> > >
> > > @@ -71,15 +127,15 @@ CameraBuffer::Private::~Private()
> > >
> > >  unsigned int CameraBuffer::Private::numPlanes() const
> > >  {
> > > -     return maps_.size();
> > > +     return planes_.size();
> > >  }
> > >
> > >  Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> > >  {
> > > -     if (plane >= maps_.size())
> > > +     if (plane >= planes_.size())
> > >               return {};
> > >
> > > -     return maps_[plane];
> > > +     return planes_[plane];
> > >  }
> > >
> > >  size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const

On Fri, Aug 27, 2021 at 8:36 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Tomasz,
>
> On Fri, Aug 27, 2021 at 07:08:30PM +0900, Tomasz Figa wrote:
> > On Wed, Aug 25, 2021 at 5:34 PM Jacopo Mondi wrote:
> > > On Wed, Aug 25, 2021 at 01:44:08PM +0900, Hirokazu Honda wrote:
> > > > buffer_hanlde_t doesn't provide sufficient info to map a buffer
> > > > properly. cros::CameraBufferManager enables handling the buffer on
> > > > ChromeOS, but no way is provided for other platforms.
> > > >
> > > > Therefore, we put the assumption that planes are in the same buffer
> > > > and they are consecutive. This modifies the way of mapping in
> > > > generic_camera_buffer with the assumption.
> > > >
> > > > Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
> > > > ---
> > > >  src/android/camera_buffer.h              |  14 ++-
> > > >  src/android/camera_stream.cpp            |   4 +-
> > > >  src/android/mm/cros_camera_buffer.cpp    |   7 +-
> > > >  src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
> > > >  4 files changed, 99 insertions(+), 30 deletions(-)
> > > >
> > > > diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
> > > > index c4e3a9e7..87df2570 100644
> > > > --- a/src/android/camera_buffer.h
> > > > +++ b/src/android/camera_buffer.h
> > > > @@ -11,13 +11,17 @@
> > > >
> > > >  #include <libcamera/base/class.h>
> > > >  #include <libcamera/base/span.h>
> > > > +#include <libcamera/geometry.h>
> > > > +#include <libcamera/pixel_format.h>
> > > >
> > > >  class CameraBuffer final : public libcamera::Extensible
> > > >  {
> > > >       LIBCAMERA_DECLARE_PRIVATE()
> > > >
> > > >  public:
> > > > -     CameraBuffer(buffer_handle_t camera3Buffer, int flags);
> > > > +     CameraBuffer(buffer_handle_t camera3Buffer,
> > > > +                  libcamera::PixelFormat pixelFormat,
> > > > +                  const libcamera::Size &size, int flags);
> > > >       ~CameraBuffer();
> > > >
> > > >       bool isValid() const;
> > > > @@ -31,8 +35,12 @@ public:
> > > >  };
> > > >
> > > >  #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION                          \
> > > > -CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags) \
> > > > -     : Extensible(std::make_unique<Private>(this, camera3Buffer, flags)) \
> > > > +CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer,            \
> > > > +                        libcamera::PixelFormat pixelFormat,          \
> > > > +                        const libcamera::Size &size, int flags)      \
> > > > +     : Extensible(std::make_unique<Private>(this, camera3Buffer,     \
> > > > +                                            pixelFormat, size,       \
> > > > +                                            flags))                  \
> > > >  {                                                                    \
> > > >  }                                                                    \
> > > >  CameraBuffer::~CameraBuffer()                                                \
> > > > diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> > > > index 61b44183..01909ec7 100644
> > > > --- a/src/android/camera_stream.cpp
> > > > +++ b/src/android/camera_stream.cpp
> > > > @@ -110,7 +110,9 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
> > > >        * \todo Buffer mapping and processing should be moved to a
> > > >        * separate thread.
> > > >        */
> > > > -     CameraBuffer dest(camera3Dest, PROT_READ | PROT_WRITE);
> > > > +     const StreamConfiguration &output = configuration();
> > > > +     CameraBuffer dest(camera3Dest, formats::MJPEG, output.size,
> > > > +                       PROT_READ | PROT_WRITE);
> > > >       if (!dest.isValid()) {
> > > >               LOG(HAL, Error) << "Failed to map android blob buffer";
> > > >               return -EINVAL;
> > > > diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> > > > index e8783ff8..50732637 100644
> > > > --- a/src/android/mm/cros_camera_buffer.cpp
> > > > +++ b/src/android/mm/cros_camera_buffer.cpp
> > > > @@ -20,8 +20,9 @@ class CameraBuffer::Private : public Extensible::Private
> > > >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > > >
> > > >  public:
> > > > -     Private(CameraBuffer *cameraBuffer,
> > > > -             buffer_handle_t camera3Buffer, int flags);
> > > > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > > +             int flags);
> > > >       ~Private();
> > > >
> > > >       bool isValid() const { return valid_; }
> > > > @@ -46,6 +47,8 @@ private:
> > > >
> > > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > >                              buffer_handle_t camera3Buffer,
> > > > +                            [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> > > > +                            [[maybe_unused]] const libcamera::Size &size,
> > > >                              [[maybe_unused]] int flags)
> > > >       : handle_(camera3Buffer), numPlanes_(0), valid_(false),
> > > >         registered_(false)
> > > > diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> > > > index b3af194c..0bfdc2ba 100644
> > > > --- a/src/android/mm/generic_camera_buffer.cpp
> > > > +++ b/src/android/mm/generic_camera_buffer.cpp
> > > > @@ -12,6 +12,7 @@
> > > >
> > > >  #include <libcamera/base/log.h>
> > > >
> > > > +#include "libcamera/internal/formats.h"
> > > >  #include "libcamera/internal/mapped_framebuffer.h"
> > > >
> > > >  using namespace libcamera;
> > > > @@ -24,8 +25,9 @@ class CameraBuffer::Private : public Extensible::Private,
> > > >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > > >
> > > >  public:
> > > > -     Private(CameraBuffer *cameraBuffer,
> > > > -             buffer_handle_t camera3Buffer, int flags);
> > > > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > > +             int flags);
> > > >       ~Private();
> > > >
> > > >       unsigned int numPlanes() const;
> > > > @@ -33,35 +35,89 @@ public:
> > > >       Span<uint8_t> plane(unsigned int plane);
> > > >
> > > >       size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > > > +
> > > > +private:
> > > > +     /* \todo Remove planes_ when it will be added to MappedBuffer */
> > > > +     std::vector<Span<uint8_t>> planes_;
> > > >  };
> > > >
> > > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > > -                            buffer_handle_t camera3Buffer, int flags)
> > > > +                            buffer_handle_t camera3Buffer,
> > > > +                            libcamera::PixelFormat pixelFormat,
> > > > +                            const libcamera::Size &size, int flags)
> > > >  {
> > > > -     maps_.reserve(camera3Buffer->numFds);
> > > >       error_ = 0;
> > > > -
> > > > +     /*
> > > > +      * As Android doesn't offer an API to query buffer layouts, assume for
> > > > +      * now that the buffer is backed by a single dmabuf, with planes being
> > > > +      * stored contiguously.
> > > > +      */
> > > > +     int fd = -1;
> > > >       for (int i = 0; i < camera3Buffer->numFds; i++) {
> > >
> > > unsigned int i
> > >
> > > > -             if (camera3Buffer->data[i] == -1)
> > > > +             if (camera3Buffer->data[i] == -1 ||
> > > > +                 camera3Buffer->data[i] == fd) {
> > > >                       continue;
> > > > -
> > > > -             off_t length = lseek(camera3Buffer->data[i], 0, SEEK_END);
> > > > -             if (length < 0) {
> > > > -                     error_ = -errno;
> > > > -                     LOG(HAL, Error) << "Failed to query plane length";
> > > > -                     break;
> > > >               }
> > > >
> > > > -             void *address = mmap(nullptr, length, flags, MAP_SHARED,
> > > > -                                  camera3Buffer->data[i], 0);
> > > > -             if (address == MAP_FAILED) {
> > > > -                     error_ = -errno;
> > > > -                     LOG(HAL, Error) << "Failed to mmap plane";
> > > > -                     break;
> > > > -             }
> > > > +             if (fd != -1)
> > > > +                     LOG(HAL, Fatal) << "Discontiguous planes are not supported";
> > >
> > > Do we just warn ? Or exit with error ? See the below question
> > >
> > > > +             fd = camera3Buffer->data[i];
> > >
> > > This assigns fd to the 'next' valid data[i].fd. I might have missed
> > > what is the policy here if we have more than one valid dmabuf fds.
> > >
> > > Currently you warn and use the last valid one. I would instead error out,
> > > or warn but use the first available one (even if that would result in
> > > undefined behaviour, or most probably an access to non valid memory when
> > > creating planes below).
> > >
> > > Do you have a use case for formats with planes allocated in different
> > > buffers that you need to support ? Or can we error out without causing
> > > regressions ?
> > >
> > > > +     }
> > >
> > > The loop is pretty convoluted. If I'm not mistaken what you want to
> > > verify is that
> > > 1) Either all data[i].fd are the same
> >
> > This is actually not something that would happen in practice, because
> > the handles are passed via Binder and even if the source puts the same
> > FD for all the planes, the receiver would see all different FDs,
> > because Binder would create a new FD for each array element.
>
> Sounds like there's room for improvement in binder then. Nevertheless,
> we certainly want to support the case where the fds will be different
> but all refer to the same dmabuf. The main blocker for this is the
> ability to actually test it on Android, which I'm working on.
>

Do we really need that strict validation? I think we could just take
the first DMA-buf if the offsets match the non-M format layout. There
is no practical case when libcamera would get more than 1 DMA-buf to
be used with hardware that only supports non-M formats.

> > > 2) All but the data[0].fd are -1
> > >
> > > Wouldn't it be nicer as
> > >
> > >         int fd = camera3Buffer->data[0].fd;
> > >         for (unsigned int i = 1; i < camera3Buffer->numFds; ++i) {
> > >                 if (camera3Buffer->data[i].fd != -1)
> > >                         continue;
> > >
> > >                 if (camera3Buffer->data[i].fd != fd)
> > >                         /* Here I would error out */
> > >         }
> > >         if (fd == -1) {
> > >                 /* No valid fds, error out */
> > >         }
> > >
> > > > +
> > > > +     if (fd != -1) {
> > >
> > > Shouldn't this be fd == -1 ? As in "no valid fd found ?"
> > > If I'm not mistaken checking for fd != -1 should fail all the times as
> > > at least one valid fd should be found. On which platform have you
> > > tested this patch ?
> > >
> > > > +             error_ = -EINVAL;
> > > > +             LOG(HAL, Error) << "No valid file descriptor";
> > > > +             return;
> > > > +     }
> > > >
> > > > -             maps_.emplace_back(static_cast<uint8_t *>(address),
> > > > -                                static_cast<size_t>(length));
> > > > +     const auto &info = libcamera::PixelFormatInfo::info(pixelFormat);
> > > > +     if (!info.isValid()) {
> > > > +             error_ = -EINVAL;
> > > > +             LOG(HAL, Error) << "Invalid pixel format: "
> > > > +                             << pixelFormat.toString();
> > > > +             return;
> > > > +     }
> > >
> > > We could check this at the very beginning of the function and avoid
> > > looping on fds if the format is invalid.
> > >
> > > > +
> > > > +     off_t bufferLength = lseek(fd, 0, SEEK_END);
> > > > +     if (bufferLength < 0) {
> > > > +             error_ = -errno;
> > > > +             LOG(HAL, Error) << "Failed to get buffer length";
> > > > +             return;
> > > > +     }
> > > > +
> > > > +     void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> > > > +     if (address == MAP_FAILED) {
> > > > +             error_ = -errno;
> > > > +             LOG(HAL, Error) << "Failed to mmap plane";
> > > > +             return;
> > > > +     }
> > > > +     maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> > > > +
> > > > +     const unsigned int numPlanes = info.numPlanes();
> > > > +     planes_.resize(numPlanes);
> > > > +     unsigned int offset = 0;
> > > > +     for (unsigned int i = 0; i < numPlanes; ++i) {
> > > > +             /*
> > > > +              * \todo Remove if this plane size computation function is
> > > > +              * added to PixelFormatInfo.
> > > > +              */
> > > > +             const unsigned int vertSubSample = info.planes[i].verticalSubSampling;
> > > > +             const unsigned int stride = info.stride(size.width, i, 1u);
> > > > +             const unsigned int planeSize =
> > > > +                     stride * ((size.height + vertSubSample - 1) / vertSubSample);
> > > > +
> > > > +             planes_[i] = libcamera::Span<uint8_t>(
> > > > +                     static_cast<uint8_t *>(address) + offset, planeSize);
> > > > +
> > > > +             if (bufferLength < offset + planeSize) {
> > > > +                     error_ = -EINVAL;
> > > > +                     LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> > > > +                                     << ", buffer length=" << bufferLength
> > > > +                                     << ", offset=" << offset
> > > > +                                     << ", size=" << planeSize;
> > > > +                     return;
> > > > +             }
> > > > +             offset += planeSize;
> > > >       }
> > > >  }
> > > >
> > > > @@ -71,15 +127,15 @@ CameraBuffer::Private::~Private()
> > > >
> > > >  unsigned int CameraBuffer::Private::numPlanes() const
> > > >  {
> > > > -     return maps_.size();
> > > > +     return planes_.size();
> > > >  }
> > > >
> > > >  Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> > > >  {
> > > > -     if (plane >= maps_.size())
> > > > +     if (plane >= planes_.size())
> > > >               return {};
> > > >
> > > > -     return maps_[plane];
> > > > +     return planes_[plane];
> > > >  }
> > > >
> > > >  size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const
>
> --
> Regards,
>
> Laurent Pinchart

Hi Tomasz,

On Fri, Aug 27, 2021 at 09:01:07PM +0900, Tomasz Figa wrote:
> On Fri, Aug 27, 2021 at 8:36 PM Laurent Pinchart wrote:
> > On Fri, Aug 27, 2021 at 07:08:30PM +0900, Tomasz Figa wrote:
> > > On Wed, Aug 25, 2021 at 5:34 PM Jacopo Mondi wrote:
> > > > On Wed, Aug 25, 2021 at 01:44:08PM +0900, Hirokazu Honda wrote:
> > > > > buffer_hanlde_t doesn't provide sufficient info to map a buffer
> > > > > properly. cros::CameraBufferManager enables handling the buffer on
> > > > > ChromeOS, but no way is provided for other platforms.
> > > > >
> > > > > Therefore, we put the assumption that planes are in the same buffer
> > > > > and they are consecutive. This modifies the way of mapping in
> > > > > generic_camera_buffer with the assumption.
> > > > >
> > > > > Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
> > > > > ---
> > > > >  src/android/camera_buffer.h              |  14 ++-
> > > > >  src/android/camera_stream.cpp            |   4 +-
> > > > >  src/android/mm/cros_camera_buffer.cpp    |   7 +-
> > > > >  src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
> > > > >  4 files changed, 99 insertions(+), 30 deletions(-)
> > > > >
> > > > > diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
> > > > > index c4e3a9e7..87df2570 100644
> > > > > --- a/src/android/camera_buffer.h
> > > > > +++ b/src/android/camera_buffer.h
> > > > > @@ -11,13 +11,17 @@
> > > > >
> > > > >  #include <libcamera/base/class.h>
> > > > >  #include <libcamera/base/span.h>
> > > > > +#include <libcamera/geometry.h>
> > > > > +#include <libcamera/pixel_format.h>
> > > > >
> > > > >  class CameraBuffer final : public libcamera::Extensible
> > > > >  {
> > > > >       LIBCAMERA_DECLARE_PRIVATE()
> > > > >
> > > > >  public:
> > > > > -     CameraBuffer(buffer_handle_t camera3Buffer, int flags);
> > > > > +     CameraBuffer(buffer_handle_t camera3Buffer,
> > > > > +                  libcamera::PixelFormat pixelFormat,
> > > > > +                  const libcamera::Size &size, int flags);
> > > > >       ~CameraBuffer();
> > > > >
> > > > >       bool isValid() const;
> > > > > @@ -31,8 +35,12 @@ public:
> > > > >  };
> > > > >
> > > > >  #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION                          \
> > > > > -CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags) \
> > > > > -     : Extensible(std::make_unique<Private>(this, camera3Buffer, flags)) \
> > > > > +CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer,            \
> > > > > +                        libcamera::PixelFormat pixelFormat,          \
> > > > > +                        const libcamera::Size &size, int flags)      \
> > > > > +     : Extensible(std::make_unique<Private>(this, camera3Buffer,     \
> > > > > +                                            pixelFormat, size,       \
> > > > > +                                            flags))                  \
> > > > >  {                                                                    \
> > > > >  }                                                                    \
> > > > >  CameraBuffer::~CameraBuffer()                                                \
> > > > > diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> > > > > index 61b44183..01909ec7 100644
> > > > > --- a/src/android/camera_stream.cpp
> > > > > +++ b/src/android/camera_stream.cpp
> > > > > @@ -110,7 +110,9 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
> > > > >        * \todo Buffer mapping and processing should be moved to a
> > > > >        * separate thread.
> > > > >        */
> > > > > -     CameraBuffer dest(camera3Dest, PROT_READ | PROT_WRITE);
> > > > > +     const StreamConfiguration &output = configuration();
> > > > > +     CameraBuffer dest(camera3Dest, formats::MJPEG, output.size,
> > > > > +                       PROT_READ | PROT_WRITE);
> > > > >       if (!dest.isValid()) {
> > > > >               LOG(HAL, Error) << "Failed to map android blob buffer";
> > > > >               return -EINVAL;
> > > > > diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> > > > > index e8783ff8..50732637 100644
> > > > > --- a/src/android/mm/cros_camera_buffer.cpp
> > > > > +++ b/src/android/mm/cros_camera_buffer.cpp
> > > > > @@ -20,8 +20,9 @@ class CameraBuffer::Private : public Extensible::Private
> > > > >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > > > >
> > > > >  public:
> > > > > -     Private(CameraBuffer *cameraBuffer,
> > > > > -             buffer_handle_t camera3Buffer, int flags);
> > > > > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > > > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > > > +             int flags);
> > > > >       ~Private();
> > > > >
> > > > >       bool isValid() const { return valid_; }
> > > > > @@ -46,6 +47,8 @@ private:
> > > > >
> > > > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > > >                              buffer_handle_t camera3Buffer,
> > > > > +                            [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> > > > > +                            [[maybe_unused]] const libcamera::Size &size,
> > > > >                              [[maybe_unused]] int flags)
> > > > >       : handle_(camera3Buffer), numPlanes_(0), valid_(false),
> > > > >         registered_(false)
> > > > > diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> > > > > index b3af194c..0bfdc2ba 100644
> > > > > --- a/src/android/mm/generic_camera_buffer.cpp
> > > > > +++ b/src/android/mm/generic_camera_buffer.cpp
> > > > > @@ -12,6 +12,7 @@
> > > > >
> > > > >  #include <libcamera/base/log.h>
> > > > >
> > > > > +#include "libcamera/internal/formats.h"
> > > > >  #include "libcamera/internal/mapped_framebuffer.h"
> > > > >
> > > > >  using namespace libcamera;
> > > > > @@ -24,8 +25,9 @@ class CameraBuffer::Private : public Extensible::Private,
> > > > >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > > > >
> > > > >  public:
> > > > > -     Private(CameraBuffer *cameraBuffer,
> > > > > -             buffer_handle_t camera3Buffer, int flags);
> > > > > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > > > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > > > +             int flags);
> > > > >       ~Private();
> > > > >
> > > > >       unsigned int numPlanes() const;
> > > > > @@ -33,35 +35,89 @@ public:
> > > > >       Span<uint8_t> plane(unsigned int plane);
> > > > >
> > > > >       size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > > > > +
> > > > > +private:
> > > > > +     /* \todo Remove planes_ when it will be added to MappedBuffer */
> > > > > +     std::vector<Span<uint8_t>> planes_;
> > > > >  };
> > > > >
> > > > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > > > -                            buffer_handle_t camera3Buffer, int flags)
> > > > > +                            buffer_handle_t camera3Buffer,
> > > > > +                            libcamera::PixelFormat pixelFormat,
> > > > > +                            const libcamera::Size &size, int flags)
> > > > >  {
> > > > > -     maps_.reserve(camera3Buffer->numFds);
> > > > >       error_ = 0;
> > > > > -
> > > > > +     /*
> > > > > +      * As Android doesn't offer an API to query buffer layouts, assume for
> > > > > +      * now that the buffer is backed by a single dmabuf, with planes being
> > > > > +      * stored contiguously.
> > > > > +      */
> > > > > +     int fd = -1;
> > > > >       for (int i = 0; i < camera3Buffer->numFds; i++) {
> > > >
> > > > unsigned int i
> > > >
> > > > > -             if (camera3Buffer->data[i] == -1)
> > > > > +             if (camera3Buffer->data[i] == -1 ||
> > > > > +                 camera3Buffer->data[i] == fd) {
> > > > >                       continue;
> > > > > -
> > > > > -             off_t length = lseek(camera3Buffer->data[i], 0, SEEK_END);
> > > > > -             if (length < 0) {
> > > > > -                     error_ = -errno;
> > > > > -                     LOG(HAL, Error) << "Failed to query plane length";
> > > > > -                     break;
> > > > >               }
> > > > >
> > > > > -             void *address = mmap(nullptr, length, flags, MAP_SHARED,
> > > > > -                                  camera3Buffer->data[i], 0);
> > > > > -             if (address == MAP_FAILED) {
> > > > > -                     error_ = -errno;
> > > > > -                     LOG(HAL, Error) << "Failed to mmap plane";
> > > > > -                     break;
> > > > > -             }
> > > > > +             if (fd != -1)
> > > > > +                     LOG(HAL, Fatal) << "Discontiguous planes are not supported";
> > > >
> > > > Do we just warn ? Or exit with error ? See the below question
> > > >
> > > > > +             fd = camera3Buffer->data[i];
> > > >
> > > > This assigns fd to the 'next' valid data[i].fd. I might have missed
> > > > what is the policy here if we have more than one valid dmabuf fds.
> > > >
> > > > Currently you warn and use the last valid one. I would instead error out,
> > > > or warn but use the first available one (even if that would result in
> > > > undefined behaviour, or most probably an access to non valid memory when
> > > > creating planes below).
> > > >
> > > > Do you have a use case for formats with planes allocated in different
> > > > buffers that you need to support ? Or can we error out without causing
> > > > regressions ?
> > > >
> > > > > +     }
> > > >
> > > > The loop is pretty convoluted. If I'm not mistaken what you want to
> > > > verify is that
> > > > 1) Either all data[i].fd are the same
> > >
> > > This is actually not something that would happen in practice, because
> > > the handles are passed via Binder and even if the source puts the same
> > > FD for all the planes, the receiver would see all different FDs,
> > > because Binder would create a new FD for each array element.
> >
> > Sounds like there's room for improvement in binder then. Nevertheless,
> > we certainly want to support the case where the fds will be different
> > but all refer to the same dmabuf. The main blocker for this is the
> > ability to actually test it on Android, which I'm working on.
> 
> Do we really need that strict validation? I think we could just take
> the first DMA-buf if the offsets match the non-M format layout. There
> is no practical case when libcamera would get more than 1 DMA-buf to
> be used with hardware that only supports non-M formats.

It's an easy check to implement, so I'd rather do it now that my memory
is fresh than running into a problem in a year and spend days debugging
it :-)

> > > > 2) All but the data[0].fd are -1
> > > >
> > > > Wouldn't it be nicer as
> > > >
> > > >         int fd = camera3Buffer->data[0].fd;
> > > >         for (unsigned int i = 1; i < camera3Buffer->numFds; ++i) {
> > > >                 if (camera3Buffer->data[i].fd != -1)
> > > >                         continue;
> > > >
> > > >                 if (camera3Buffer->data[i].fd != fd)
> > > >                         /* Here I would error out */
> > > >         }
> > > >         if (fd == -1) {
> > > >                 /* No valid fds, error out */
> > > >         }
> > > >
> > > > > +
> > > > > +     if (fd != -1) {
> > > >
> > > > Shouldn't this be fd == -1 ? As in "no valid fd found ?"
> > > > If I'm not mistaken checking for fd != -1 should fail all the times as
> > > > at least one valid fd should be found. On which platform have you
> > > > tested this patch ?
> > > >
> > > > > +             error_ = -EINVAL;
> > > > > +             LOG(HAL, Error) << "No valid file descriptor";
> > > > > +             return;
> > > > > +     }
> > > > >
> > > > > -             maps_.emplace_back(static_cast<uint8_t *>(address),
> > > > > -                                static_cast<size_t>(length));
> > > > > +     const auto &info = libcamera::PixelFormatInfo::info(pixelFormat);
> > > > > +     if (!info.isValid()) {
> > > > > +             error_ = -EINVAL;
> > > > > +             LOG(HAL, Error) << "Invalid pixel format: "
> > > > > +                             << pixelFormat.toString();
> > > > > +             return;
> > > > > +     }
> > > >
> > > > We could check this at the very beginning of the function and avoid
> > > > looping on fds if the format is invalid.
> > > >
> > > > > +
> > > > > +     off_t bufferLength = lseek(fd, 0, SEEK_END);
> > > > > +     if (bufferLength < 0) {
> > > > > +             error_ = -errno;
> > > > > +             LOG(HAL, Error) << "Failed to get buffer length";
> > > > > +             return;
> > > > > +     }
> > > > > +
> > > > > +     void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> > > > > +     if (address == MAP_FAILED) {
> > > > > +             error_ = -errno;
> > > > > +             LOG(HAL, Error) << "Failed to mmap plane";
> > > > > +             return;
> > > > > +     }
> > > > > +     maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> > > > > +
> > > > > +     const unsigned int numPlanes = info.numPlanes();
> > > > > +     planes_.resize(numPlanes);
> > > > > +     unsigned int offset = 0;
> > > > > +     for (unsigned int i = 0; i < numPlanes; ++i) {
> > > > > +             /*
> > > > > +              * \todo Remove if this plane size computation function is
> > > > > +              * added to PixelFormatInfo.
> > > > > +              */
> > > > > +             const unsigned int vertSubSample = info.planes[i].verticalSubSampling;
> > > > > +             const unsigned int stride = info.stride(size.width, i, 1u);
> > > > > +             const unsigned int planeSize =
> > > > > +                     stride * ((size.height + vertSubSample - 1) / vertSubSample);
> > > > > +
> > > > > +             planes_[i] = libcamera::Span<uint8_t>(
> > > > > +                     static_cast<uint8_t *>(address) + offset, planeSize);
> > > > > +
> > > > > +             if (bufferLength < offset + planeSize) {
> > > > > +                     error_ = -EINVAL;
> > > > > +                     LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> > > > > +                                     << ", buffer length=" << bufferLength
> > > > > +                                     << ", offset=" << offset
> > > > > +                                     << ", size=" << planeSize;
> > > > > +                     return;
> > > > > +             }
> > > > > +             offset += planeSize;
> > > > >       }
> > > > >  }
> > > > >
> > > > > @@ -71,15 +127,15 @@ CameraBuffer::Private::~Private()
> > > > >
> > > > >  unsigned int CameraBuffer::Private::numPlanes() const
> > > > >  {
> > > > > -     return maps_.size();
> > > > > +     return planes_.size();
> > > > >  }
> > > > >
> > > > >  Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> > > > >  {
> > > > > -     if (plane >= maps_.size())
> > > > > +     if (plane >= planes_.size())
> > > > >               return {};
> > > > >
> > > > > -     return maps_[plane];
> > > > > +     return planes_[plane];
> > > > >  }
> > > > >
> > > > >  size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const

On Fri, Aug 27, 2021 at 9:07 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Tomasz,
>
> On Fri, Aug 27, 2021 at 09:01:07PM +0900, Tomasz Figa wrote:
> > On Fri, Aug 27, 2021 at 8:36 PM Laurent Pinchart wrote:
> > > On Fri, Aug 27, 2021 at 07:08:30PM +0900, Tomasz Figa wrote:
> > > > On Wed, Aug 25, 2021 at 5:34 PM Jacopo Mondi wrote:
> > > > > On Wed, Aug 25, 2021 at 01:44:08PM +0900, Hirokazu Honda wrote:
> > > > > > buffer_hanlde_t doesn't provide sufficient info to map a buffer
> > > > > > properly. cros::CameraBufferManager enables handling the buffer on
> > > > > > ChromeOS, but no way is provided for other platforms.
> > > > > >
> > > > > > Therefore, we put the assumption that planes are in the same buffer
> > > > > > and they are consecutive. This modifies the way of mapping in
> > > > > > generic_camera_buffer with the assumption.
> > > > > >
> > > > > > Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
> > > > > > ---
> > > > > >  src/android/camera_buffer.h              |  14 ++-
> > > > > >  src/android/camera_stream.cpp            |   4 +-
> > > > > >  src/android/mm/cros_camera_buffer.cpp    |   7 +-
> > > > > >  src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
> > > > > >  4 files changed, 99 insertions(+), 30 deletions(-)
> > > > > >
> > > > > > diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
> > > > > > index c4e3a9e7..87df2570 100644
> > > > > > --- a/src/android/camera_buffer.h
> > > > > > +++ b/src/android/camera_buffer.h
> > > > > > @@ -11,13 +11,17 @@
> > > > > >
> > > > > >  #include <libcamera/base/class.h>
> > > > > >  #include <libcamera/base/span.h>
> > > > > > +#include <libcamera/geometry.h>
> > > > > > +#include <libcamera/pixel_format.h>
> > > > > >
> > > > > >  class CameraBuffer final : public libcamera::Extensible
> > > > > >  {
> > > > > >       LIBCAMERA_DECLARE_PRIVATE()
> > > > > >
> > > > > >  public:
> > > > > > -     CameraBuffer(buffer_handle_t camera3Buffer, int flags);
> > > > > > +     CameraBuffer(buffer_handle_t camera3Buffer,
> > > > > > +                  libcamera::PixelFormat pixelFormat,
> > > > > > +                  const libcamera::Size &size, int flags);
> > > > > >       ~CameraBuffer();
> > > > > >
> > > > > >       bool isValid() const;
> > > > > > @@ -31,8 +35,12 @@ public:
> > > > > >  };
> > > > > >
> > > > > >  #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION                          \
> > > > > > -CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags) \
> > > > > > -     : Extensible(std::make_unique<Private>(this, camera3Buffer, flags)) \
> > > > > > +CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer,            \
> > > > > > +                        libcamera::PixelFormat pixelFormat,          \
> > > > > > +                        const libcamera::Size &size, int flags)      \
> > > > > > +     : Extensible(std::make_unique<Private>(this, camera3Buffer,     \
> > > > > > +                                            pixelFormat, size,       \
> > > > > > +                                            flags))                  \
> > > > > >  {                                                                    \
> > > > > >  }                                                                    \
> > > > > >  CameraBuffer::~CameraBuffer()                                                \
> > > > > > diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> > > > > > index 61b44183..01909ec7 100644
> > > > > > --- a/src/android/camera_stream.cpp
> > > > > > +++ b/src/android/camera_stream.cpp
> > > > > > @@ -110,7 +110,9 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
> > > > > >        * \todo Buffer mapping and processing should be moved to a
> > > > > >        * separate thread.
> > > > > >        */
> > > > > > -     CameraBuffer dest(camera3Dest, PROT_READ | PROT_WRITE);
> > > > > > +     const StreamConfiguration &output = configuration();
> > > > > > +     CameraBuffer dest(camera3Dest, formats::MJPEG, output.size,
> > > > > > +                       PROT_READ | PROT_WRITE);
> > > > > >       if (!dest.isValid()) {
> > > > > >               LOG(HAL, Error) << "Failed to map android blob buffer";
> > > > > >               return -EINVAL;
> > > > > > diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> > > > > > index e8783ff8..50732637 100644
> > > > > > --- a/src/android/mm/cros_camera_buffer.cpp
> > > > > > +++ b/src/android/mm/cros_camera_buffer.cpp
> > > > > > @@ -20,8 +20,9 @@ class CameraBuffer::Private : public Extensible::Private
> > > > > >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > > > > >
> > > > > >  public:
> > > > > > -     Private(CameraBuffer *cameraBuffer,
> > > > > > -             buffer_handle_t camera3Buffer, int flags);
> > > > > > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > > > > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > > > > +             int flags);
> > > > > >       ~Private();
> > > > > >
> > > > > >       bool isValid() const { return valid_; }
> > > > > > @@ -46,6 +47,8 @@ private:
> > > > > >
> > > > > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > > > >                              buffer_handle_t camera3Buffer,
> > > > > > +                            [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> > > > > > +                            [[maybe_unused]] const libcamera::Size &size,
> > > > > >                              [[maybe_unused]] int flags)
> > > > > >       : handle_(camera3Buffer), numPlanes_(0), valid_(false),
> > > > > >         registered_(false)
> > > > > > diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> > > > > > index b3af194c..0bfdc2ba 100644
> > > > > > --- a/src/android/mm/generic_camera_buffer.cpp
> > > > > > +++ b/src/android/mm/generic_camera_buffer.cpp
> > > > > > @@ -12,6 +12,7 @@
> > > > > >
> > > > > >  #include <libcamera/base/log.h>
> > > > > >
> > > > > > +#include "libcamera/internal/formats.h"
> > > > > >  #include "libcamera/internal/mapped_framebuffer.h"
> > > > > >
> > > > > >  using namespace libcamera;
> > > > > > @@ -24,8 +25,9 @@ class CameraBuffer::Private : public Extensible::Private,
> > > > > >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > > > > >
> > > > > >  public:
> > > > > > -     Private(CameraBuffer *cameraBuffer,
> > > > > > -             buffer_handle_t camera3Buffer, int flags);
> > > > > > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > > > > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > > > > +             int flags);
> > > > > >       ~Private();
> > > > > >
> > > > > >       unsigned int numPlanes() const;
> > > > > > @@ -33,35 +35,89 @@ public:
> > > > > >       Span<uint8_t> plane(unsigned int plane);
> > > > > >
> > > > > >       size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > > > > > +
> > > > > > +private:
> > > > > > +     /* \todo Remove planes_ when it will be added to MappedBuffer */
> > > > > > +     std::vector<Span<uint8_t>> planes_;
> > > > > >  };
> > > > > >
> > > > > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > > > > -                            buffer_handle_t camera3Buffer, int flags)
> > > > > > +                            buffer_handle_t camera3Buffer,
> > > > > > +                            libcamera::PixelFormat pixelFormat,
> > > > > > +                            const libcamera::Size &size, int flags)
> > > > > >  {
> > > > > > -     maps_.reserve(camera3Buffer->numFds);
> > > > > >       error_ = 0;
> > > > > > -
> > > > > > +     /*
> > > > > > +      * As Android doesn't offer an API to query buffer layouts, assume for
> > > > > > +      * now that the buffer is backed by a single dmabuf, with planes being
> > > > > > +      * stored contiguously.
> > > > > > +      */
> > > > > > +     int fd = -1;
> > > > > >       for (int i = 0; i < camera3Buffer->numFds; i++) {
> > > > >
> > > > > unsigned int i
> > > > >
> > > > > > -             if (camera3Buffer->data[i] == -1)
> > > > > > +             if (camera3Buffer->data[i] == -1 ||
> > > > > > +                 camera3Buffer->data[i] == fd) {
> > > > > >                       continue;
> > > > > > -
> > > > > > -             off_t length = lseek(camera3Buffer->data[i], 0, SEEK_END);
> > > > > > -             if (length < 0) {
> > > > > > -                     error_ = -errno;
> > > > > > -                     LOG(HAL, Error) << "Failed to query plane length";
> > > > > > -                     break;
> > > > > >               }
> > > > > >
> > > > > > -             void *address = mmap(nullptr, length, flags, MAP_SHARED,
> > > > > > -                                  camera3Buffer->data[i], 0);
> > > > > > -             if (address == MAP_FAILED) {
> > > > > > -                     error_ = -errno;
> > > > > > -                     LOG(HAL, Error) << "Failed to mmap plane";
> > > > > > -                     break;
> > > > > > -             }
> > > > > > +             if (fd != -1)
> > > > > > +                     LOG(HAL, Fatal) << "Discontiguous planes are not supported";
> > > > >
> > > > > Do we just warn ? Or exit with error ? See the below question
> > > > >
> > > > > > +             fd = camera3Buffer->data[i];
> > > > >
> > > > > This assigns fd to the 'next' valid data[i].fd. I might have missed
> > > > > what is the policy here if we have more than one valid dmabuf fds.
> > > > >
> > > > > Currently you warn and use the last valid one. I would instead error out,
> > > > > or warn but use the first available one (even if that would result in
> > > > > undefined behaviour, or most probably an access to non valid memory when
> > > > > creating planes below).
> > > > >
> > > > > Do you have a use case for formats with planes allocated in different
> > > > > buffers that you need to support ? Or can we error out without causing
> > > > > regressions ?
> > > > >
> > > > > > +     }
> > > > >
> > > > > The loop is pretty convoluted. If I'm not mistaken what you want to
> > > > > verify is that
> > > > > 1) Either all data[i].fd are the same
> > > >
> > > > This is actually not something that would happen in practice, because
> > > > the handles are passed via Binder and even if the source puts the same
> > > > FD for all the planes, the receiver would see all different FDs,
> > > > because Binder would create a new FD for each array element.
> > >
> > > Sounds like there's room for improvement in binder then. Nevertheless,
> > > we certainly want to support the case where the fds will be different
> > > but all refer to the same dmabuf. The main blocker for this is the
> > > ability to actually test it on Android, which I'm working on.
> >
> > Do we really need that strict validation? I think we could just take
> > the first DMA-buf if the offsets match the non-M format layout. There
> > is no practical case when libcamera would get more than 1 DMA-buf to
> > be used with hardware that only supports non-M formats.
>
> It's an easy check to implement, so I'd rather do it now that my memory
> is fresh than running into a problem in a year and spend days debugging
> it :-)

Is the check cheap and compatible with older kernel versions?

Generally I don't think it would ever be possible to run into issues
with this in real life, but agreed that if the check is simple it's
better to have it.

>
> > > > > 2) All but the data[0].fd are -1
> > > > >
> > > > > Wouldn't it be nicer as
> > > > >
> > > > >         int fd = camera3Buffer->data[0].fd;
> > > > >         for (unsigned int i = 1; i < camera3Buffer->numFds; ++i) {
> > > > >                 if (camera3Buffer->data[i].fd != -1)
> > > > >                         continue;
> > > > >
> > > > >                 if (camera3Buffer->data[i].fd != fd)
> > > > >                         /* Here I would error out */
> > > > >         }
> > > > >         if (fd == -1) {
> > > > >                 /* No valid fds, error out */
> > > > >         }
> > > > >
> > > > > > +
> > > > > > +     if (fd != -1) {
> > > > >
> > > > > Shouldn't this be fd == -1 ? As in "no valid fd found ?"
> > > > > If I'm not mistaken checking for fd != -1 should fail all the times as
> > > > > at least one valid fd should be found. On which platform have you
> > > > > tested this patch ?
> > > > >
> > > > > > +             error_ = -EINVAL;
> > > > > > +             LOG(HAL, Error) << "No valid file descriptor";
> > > > > > +             return;
> > > > > > +     }
> > > > > >
> > > > > > -             maps_.emplace_back(static_cast<uint8_t *>(address),
> > > > > > -                                static_cast<size_t>(length));
> > > > > > +     const auto &info = libcamera::PixelFormatInfo::info(pixelFormat);
> > > > > > +     if (!info.isValid()) {
> > > > > > +             error_ = -EINVAL;
> > > > > > +             LOG(HAL, Error) << "Invalid pixel format: "
> > > > > > +                             << pixelFormat.toString();
> > > > > > +             return;
> > > > > > +     }
> > > > >
> > > > > We could check this at the very beginning of the function and avoid
> > > > > looping on fds if the format is invalid.
> > > > >
> > > > > > +
> > > > > > +     off_t bufferLength = lseek(fd, 0, SEEK_END);
> > > > > > +     if (bufferLength < 0) {
> > > > > > +             error_ = -errno;
> > > > > > +             LOG(HAL, Error) << "Failed to get buffer length";
> > > > > > +             return;
> > > > > > +     }
> > > > > > +
> > > > > > +     void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> > > > > > +     if (address == MAP_FAILED) {
> > > > > > +             error_ = -errno;
> > > > > > +             LOG(HAL, Error) << "Failed to mmap plane";
> > > > > > +             return;
> > > > > > +     }
> > > > > > +     maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> > > > > > +
> > > > > > +     const unsigned int numPlanes = info.numPlanes();
> > > > > > +     planes_.resize(numPlanes);
> > > > > > +     unsigned int offset = 0;
> > > > > > +     for (unsigned int i = 0; i < numPlanes; ++i) {
> > > > > > +             /*
> > > > > > +              * \todo Remove if this plane size computation function is
> > > > > > +              * added to PixelFormatInfo.
> > > > > > +              */
> > > > > > +             const unsigned int vertSubSample = info.planes[i].verticalSubSampling;
> > > > > > +             const unsigned int stride = info.stride(size.width, i, 1u);
> > > > > > +             const unsigned int planeSize =
> > > > > > +                     stride * ((size.height + vertSubSample - 1) / vertSubSample);
> > > > > > +
> > > > > > +             planes_[i] = libcamera::Span<uint8_t>(
> > > > > > +                     static_cast<uint8_t *>(address) + offset, planeSize);
> > > > > > +
> > > > > > +             if (bufferLength < offset + planeSize) {
> > > > > > +                     error_ = -EINVAL;
> > > > > > +                     LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> > > > > > +                                     << ", buffer length=" << bufferLength
> > > > > > +                                     << ", offset=" << offset
> > > > > > +                                     << ", size=" << planeSize;
> > > > > > +                     return;
> > > > > > +             }
> > > > > > +             offset += planeSize;
> > > > > >       }
> > > > > >  }
> > > > > >
> > > > > > @@ -71,15 +127,15 @@ CameraBuffer::Private::~Private()
> > > > > >
> > > > > >  unsigned int CameraBuffer::Private::numPlanes() const
> > > > > >  {
> > > > > > -     return maps_.size();
> > > > > > +     return planes_.size();
> > > > > >  }
> > > > > >
> > > > > >  Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> > > > > >  {
> > > > > > -     if (plane >= maps_.size())
> > > > > > +     if (plane >= planes_.size())
> > > > > >               return {};
> > > > > >
> > > > > > -     return maps_[plane];
> > > > > > +     return planes_[plane];
> > > > > >  }
> > > > > >
> > > > > >  size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const
>
> --
> Regards,
>
> Laurent Pinchart

Hi Tomasz,

On Fri, Aug 27, 2021 at 09:09:37PM +0900, Tomasz Figa wrote:
> On Fri, Aug 27, 2021 at 9:07 PM Laurent Pinchart wrote:
> > On Fri, Aug 27, 2021 at 09:01:07PM +0900, Tomasz Figa wrote:
> > > On Fri, Aug 27, 2021 at 8:36 PM Laurent Pinchart wrote:
> > > > On Fri, Aug 27, 2021 at 07:08:30PM +0900, Tomasz Figa wrote:
> > > > > On Wed, Aug 25, 2021 at 5:34 PM Jacopo Mondi wrote:
> > > > > > On Wed, Aug 25, 2021 at 01:44:08PM +0900, Hirokazu Honda wrote:
> > > > > > > buffer_hanlde_t doesn't provide sufficient info to map a buffer
> > > > > > > properly. cros::CameraBufferManager enables handling the buffer on
> > > > > > > ChromeOS, but no way is provided for other platforms.
> > > > > > >
> > > > > > > Therefore, we put the assumption that planes are in the same buffer
> > > > > > > and they are consecutive. This modifies the way of mapping in
> > > > > > > generic_camera_buffer with the assumption.
> > > > > > >
> > > > > > > Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
> > > > > > > ---
> > > > > > >  src/android/camera_buffer.h              |  14 ++-
> > > > > > >  src/android/camera_stream.cpp            |   4 +-
> > > > > > >  src/android/mm/cros_camera_buffer.cpp    |   7 +-
> > > > > > >  src/android/mm/generic_camera_buffer.cpp | 104 +++++++++++++++++------
> > > > > > >  4 files changed, 99 insertions(+), 30 deletions(-)
> > > > > > >
> > > > > > > diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
> > > > > > > index c4e3a9e7..87df2570 100644
> > > > > > > --- a/src/android/camera_buffer.h
> > > > > > > +++ b/src/android/camera_buffer.h
> > > > > > > @@ -11,13 +11,17 @@
> > > > > > >
> > > > > > >  #include <libcamera/base/class.h>
> > > > > > >  #include <libcamera/base/span.h>
> > > > > > > +#include <libcamera/geometry.h>
> > > > > > > +#include <libcamera/pixel_format.h>
> > > > > > >
> > > > > > >  class CameraBuffer final : public libcamera::Extensible
> > > > > > >  {
> > > > > > >       LIBCAMERA_DECLARE_PRIVATE()
> > > > > > >
> > > > > > >  public:
> > > > > > > -     CameraBuffer(buffer_handle_t camera3Buffer, int flags);
> > > > > > > +     CameraBuffer(buffer_handle_t camera3Buffer,
> > > > > > > +                  libcamera::PixelFormat pixelFormat,
> > > > > > > +                  const libcamera::Size &size, int flags);
> > > > > > >       ~CameraBuffer();
> > > > > > >
> > > > > > >       bool isValid() const;
> > > > > > > @@ -31,8 +35,12 @@ public:
> > > > > > >  };
> > > > > > >
> > > > > > >  #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION                          \
> > > > > > > -CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags) \
> > > > > > > -     : Extensible(std::make_unique<Private>(this, camera3Buffer, flags)) \
> > > > > > > +CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer,            \
> > > > > > > +                        libcamera::PixelFormat pixelFormat,          \
> > > > > > > +                        const libcamera::Size &size, int flags)      \
> > > > > > > +     : Extensible(std::make_unique<Private>(this, camera3Buffer,     \
> > > > > > > +                                            pixelFormat, size,       \
> > > > > > > +                                            flags))                  \
> > > > > > >  {                                                                    \
> > > > > > >  }                                                                    \
> > > > > > >  CameraBuffer::~CameraBuffer()                                                \
> > > > > > > diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> > > > > > > index 61b44183..01909ec7 100644
> > > > > > > --- a/src/android/camera_stream.cpp
> > > > > > > +++ b/src/android/camera_stream.cpp
> > > > > > > @@ -110,7 +110,9 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
> > > > > > >        * \todo Buffer mapping and processing should be moved to a
> > > > > > >        * separate thread.
> > > > > > >        */
> > > > > > > -     CameraBuffer dest(camera3Dest, PROT_READ | PROT_WRITE);
> > > > > > > +     const StreamConfiguration &output = configuration();
> > > > > > > +     CameraBuffer dest(camera3Dest, formats::MJPEG, output.size,
> > > > > > > +                       PROT_READ | PROT_WRITE);
> > > > > > >       if (!dest.isValid()) {
> > > > > > >               LOG(HAL, Error) << "Failed to map android blob buffer";
> > > > > > >               return -EINVAL;
> > > > > > > diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> > > > > > > index e8783ff8..50732637 100644
> > > > > > > --- a/src/android/mm/cros_camera_buffer.cpp
> > > > > > > +++ b/src/android/mm/cros_camera_buffer.cpp
> > > > > > > @@ -20,8 +20,9 @@ class CameraBuffer::Private : public Extensible::Private
> > > > > > >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > > > > > >
> > > > > > >  public:
> > > > > > > -     Private(CameraBuffer *cameraBuffer,
> > > > > > > -             buffer_handle_t camera3Buffer, int flags);
> > > > > > > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > > > > > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > > > > > +             int flags);
> > > > > > >       ~Private();
> > > > > > >
> > > > > > >       bool isValid() const { return valid_; }
> > > > > > > @@ -46,6 +47,8 @@ private:
> > > > > > >
> > > > > > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > > > > >                              buffer_handle_t camera3Buffer,
> > > > > > > +                            [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> > > > > > > +                            [[maybe_unused]] const libcamera::Size &size,
> > > > > > >                              [[maybe_unused]] int flags)
> > > > > > >       : handle_(camera3Buffer), numPlanes_(0), valid_(false),
> > > > > > >         registered_(false)
> > > > > > > diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> > > > > > > index b3af194c..0bfdc2ba 100644
> > > > > > > --- a/src/android/mm/generic_camera_buffer.cpp
> > > > > > > +++ b/src/android/mm/generic_camera_buffer.cpp
> > > > > > > @@ -12,6 +12,7 @@
> > > > > > >
> > > > > > >  #include <libcamera/base/log.h>
> > > > > > >
> > > > > > > +#include "libcamera/internal/formats.h"
> > > > > > >  #include "libcamera/internal/mapped_framebuffer.h"
> > > > > > >
> > > > > > >  using namespace libcamera;
> > > > > > > @@ -24,8 +25,9 @@ class CameraBuffer::Private : public Extensible::Private,
> > > > > > >       LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
> > > > > > >
> > > > > > >  public:
> > > > > > > -     Private(CameraBuffer *cameraBuffer,
> > > > > > > -             buffer_handle_t camera3Buffer, int flags);
> > > > > > > +     Private(CameraBuffer *cameraBuffer, buffer_handle_t camera3Buffer,
> > > > > > > +             libcamera::PixelFormat pixelFormat, const libcamera::Size &size,
> > > > > > > +             int flags);
> > > > > > >       ~Private();
> > > > > > >
> > > > > > >       unsigned int numPlanes() const;
> > > > > > > @@ -33,35 +35,89 @@ public:
> > > > > > >       Span<uint8_t> plane(unsigned int plane);
> > > > > > >
> > > > > > >       size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > > > > > > +
> > > > > > > +private:
> > > > > > > +     /* \todo Remove planes_ when it will be added to MappedBuffer */
> > > > > > > +     std::vector<Span<uint8_t>> planes_;
> > > > > > >  };
> > > > > > >
> > > > > > >  CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > > > > > -                            buffer_handle_t camera3Buffer, int flags)
> > > > > > > +                            buffer_handle_t camera3Buffer,
> > > > > > > +                            libcamera::PixelFormat pixelFormat,
> > > > > > > +                            const libcamera::Size &size, int flags)
> > > > > > >  {
> > > > > > > -     maps_.reserve(camera3Buffer->numFds);
> > > > > > >       error_ = 0;
> > > > > > > -
> > > > > > > +     /*
> > > > > > > +      * As Android doesn't offer an API to query buffer layouts, assume for
> > > > > > > +      * now that the buffer is backed by a single dmabuf, with planes being
> > > > > > > +      * stored contiguously.
> > > > > > > +      */
> > > > > > > +     int fd = -1;
> > > > > > >       for (int i = 0; i < camera3Buffer->numFds; i++) {
> > > > > >
> > > > > > unsigned int i
> > > > > >
> > > > > > > -             if (camera3Buffer->data[i] == -1)
> > > > > > > +             if (camera3Buffer->data[i] == -1 ||
> > > > > > > +                 camera3Buffer->data[i] == fd) {
> > > > > > >                       continue;
> > > > > > > -
> > > > > > > -             off_t length = lseek(camera3Buffer->data[i], 0, SEEK_END);
> > > > > > > -             if (length < 0) {
> > > > > > > -                     error_ = -errno;
> > > > > > > -                     LOG(HAL, Error) << "Failed to query plane length";
> > > > > > > -                     break;
> > > > > > >               }
> > > > > > >
> > > > > > > -             void *address = mmap(nullptr, length, flags, MAP_SHARED,
> > > > > > > -                                  camera3Buffer->data[i], 0);
> > > > > > > -             if (address == MAP_FAILED) {
> > > > > > > -                     error_ = -errno;
> > > > > > > -                     LOG(HAL, Error) << "Failed to mmap plane";
> > > > > > > -                     break;
> > > > > > > -             }
> > > > > > > +             if (fd != -1)
> > > > > > > +                     LOG(HAL, Fatal) << "Discontiguous planes are not supported";
> > > > > >
> > > > > > Do we just warn ? Or exit with error ? See the below question
> > > > > >
> > > > > > > +             fd = camera3Buffer->data[i];
> > > > > >
> > > > > > This assigns fd to the 'next' valid data[i].fd. I might have missed
> > > > > > what is the policy here if we have more than one valid dmabuf fds.
> > > > > >
> > > > > > Currently you warn and use the last valid one. I would instead error out,
> > > > > > or warn but use the first available one (even if that would result in
> > > > > > undefined behaviour, or most probably an access to non valid memory when
> > > > > > creating planes below).
> > > > > >
> > > > > > Do you have a use case for formats with planes allocated in different
> > > > > > buffers that you need to support ? Or can we error out without causing
> > > > > > regressions ?
> > > > > >
> > > > > > > +     }
> > > > > >
> > > > > > The loop is pretty convoluted. If I'm not mistaken what you want to
> > > > > > verify is that
> > > > > > 1) Either all data[i].fd are the same
> > > > >
> > > > > This is actually not something that would happen in practice, because
> > > > > the handles are passed via Binder and even if the source puts the same
> > > > > FD for all the planes, the receiver would see all different FDs,
> > > > > because Binder would create a new FD for each array element.
> > > >
> > > > Sounds like there's room for improvement in binder then. Nevertheless,
> > > > we certainly want to support the case where the fds will be different
> > > > but all refer to the same dmabuf. The main blocker for this is the
> > > > ability to actually test it on Android, which I'm working on.
> > >
> > > Do we really need that strict validation? I think we could just take
> > > the first DMA-buf if the offsets match the non-M format layout. There
> > > is no practical case when libcamera would get more than 1 DMA-buf to
> > > be used with hardware that only supports non-M formats.
> >
> > It's an easy check to implement, so I'd rather do it now that my memory
> > is fresh than running into a problem in a year and spend days debugging
> > it :-)
> 
> Is the check cheap and compatible with older kernel versions?

As far as I can tell, yes, but I'll double-check of course.

> Generally I don't think it would ever be possible to run into issues
> with this in real life, but agreed that if the check is simple it's
> better to have it.
> 
> > > > > > 2) All but the data[0].fd are -1
> > > > > >
> > > > > > Wouldn't it be nicer as
> > > > > >
> > > > > >         int fd = camera3Buffer->data[0].fd;
> > > > > >         for (unsigned int i = 1; i < camera3Buffer->numFds; ++i) {
> > > > > >                 if (camera3Buffer->data[i].fd != -1)
> > > > > >                         continue;
> > > > > >
> > > > > >                 if (camera3Buffer->data[i].fd != fd)
> > > > > >                         /* Here I would error out */
> > > > > >         }
> > > > > >         if (fd == -1) {
> > > > > >                 /* No valid fds, error out */
> > > > > >         }
> > > > > >
> > > > > > > +
> > > > > > > +     if (fd != -1) {
> > > > > >
> > > > > > Shouldn't this be fd == -1 ? As in "no valid fd found ?"
> > > > > > If I'm not mistaken checking for fd != -1 should fail all the times as
> > > > > > at least one valid fd should be found. On which platform have you
> > > > > > tested this patch ?
> > > > > >
> > > > > > > +             error_ = -EINVAL;
> > > > > > > +             LOG(HAL, Error) << "No valid file descriptor";
> > > > > > > +             return;
> > > > > > > +     }
> > > > > > >
> > > > > > > -             maps_.emplace_back(static_cast<uint8_t *>(address),
> > > > > > > -                                static_cast<size_t>(length));
> > > > > > > +     const auto &info = libcamera::PixelFormatInfo::info(pixelFormat);
> > > > > > > +     if (!info.isValid()) {
> > > > > > > +             error_ = -EINVAL;
> > > > > > > +             LOG(HAL, Error) << "Invalid pixel format: "
> > > > > > > +                             << pixelFormat.toString();
> > > > > > > +             return;
> > > > > > > +     }
> > > > > >
> > > > > > We could check this at the very beginning of the function and avoid
> > > > > > looping on fds if the format is invalid.
> > > > > >
> > > > > > > +
> > > > > > > +     off_t bufferLength = lseek(fd, 0, SEEK_END);
> > > > > > > +     if (bufferLength < 0) {
> > > > > > > +             error_ = -errno;
> > > > > > > +             LOG(HAL, Error) << "Failed to get buffer length";
> > > > > > > +             return;
> > > > > > > +     }
> > > > > > > +
> > > > > > > +     void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> > > > > > > +     if (address == MAP_FAILED) {
> > > > > > > +             error_ = -errno;
> > > > > > > +             LOG(HAL, Error) << "Failed to mmap plane";
> > > > > > > +             return;
> > > > > > > +     }
> > > > > > > +     maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> > > > > > > +
> > > > > > > +     const unsigned int numPlanes = info.numPlanes();
> > > > > > > +     planes_.resize(numPlanes);
> > > > > > > +     unsigned int offset = 0;
> > > > > > > +     for (unsigned int i = 0; i < numPlanes; ++i) {
> > > > > > > +             /*
> > > > > > > +              * \todo Remove if this plane size computation function is
> > > > > > > +              * added to PixelFormatInfo.
> > > > > > > +              */
> > > > > > > +             const unsigned int vertSubSample = info.planes[i].verticalSubSampling;
> > > > > > > +             const unsigned int stride = info.stride(size.width, i, 1u);
> > > > > > > +             const unsigned int planeSize =
> > > > > > > +                     stride * ((size.height + vertSubSample - 1) / vertSubSample);
> > > > > > > +
> > > > > > > +             planes_[i] = libcamera::Span<uint8_t>(
> > > > > > > +                     static_cast<uint8_t *>(address) + offset, planeSize);
> > > > > > > +
> > > > > > > +             if (bufferLength < offset + planeSize) {
> > > > > > > +                     error_ = -EINVAL;
> > > > > > > +                     LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> > > > > > > +                                     << ", buffer length=" << bufferLength
> > > > > > > +                                     << ", offset=" << offset
> > > > > > > +                                     << ", size=" << planeSize;
> > > > > > > +                     return;
> > > > > > > +             }
> > > > > > > +             offset += planeSize;
> > > > > > >       }
> > > > > > >  }
> > > > > > >
> > > > > > > @@ -71,15 +127,15 @@ CameraBuffer::Private::~Private()
> > > > > > >
> > > > > > >  unsigned int CameraBuffer::Private::numPlanes() const
> > > > > > >  {
> > > > > > > -     return maps_.size();
> > > > > > > +     return planes_.size();
> > > > > > >  }
> > > > > > >
> > > > > > >  Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> > > > > > >  {
> > > > > > > -     if (plane >= maps_.size())
> > > > > > > +     if (plane >= planes_.size())
> > > > > > >               return {};
> > > > > > >
> > > > > > > -     return maps_[plane];
> > > > > > > +     return planes_[plane];
> > > > > > >  }
> > > > > > >
> > > > > > >  size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const