[{"id":17416,"web_url":"https://patchwork.libcamera.org/comment/17416/","msgid":"","date":"2021-06-06T18:56:25","subject":"Re: [libcamera-devel] [RFC PATCH 10/10] v4l2: V4L2Camera: Return\n\tint in getBufferFd()","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Hiro,\n\nThank you for the patch.\n\nOn Thu, Apr 15, 2021 at 05:38:43PM +0900, Hirokazu Honda wrote:\n> V4L2Camera::getBufferFd() returns FileDescriptor. However, the\n> file descriptor is still owned by V4L2Camera. It should rather\n> return an integer to represent V4L2Camera doesn't have the\n> ownership of the file descriptor.\n\nThe FileDescriptor class doesn't imply ownership, as it's similar to a\nshared_ptr<>. I'm not against this patch, but why do you think\nFileDescriptor is bad here ?\n\n> Signed-off-by: Hirokazu Honda \n> ---\n> src/v4l2/v4l2_camera.cpp | 6 +++---\n> src/v4l2/v4l2_camera.h | 2 +-\n> src/v4l2/v4l2_camera_proxy.cpp | 6 +++---\n> 3 files changed, 7 insertions(+), 7 deletions(-)\n> \n> diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp\n> index 97825c71..cccc6749 100644\n> --- a/src/v4l2/v4l2_camera.cpp\n> +++ b/src/v4l2/v4l2_camera.cpp\n> @@ -186,16 +186,16 @@ void V4L2Camera::freeBuffers()\n> \tbufferAllocator_->free(stream);\n> }\n> \n> -FileDescriptor V4L2Camera::getBufferFd(unsigned int index)\n> +int V4L2Camera::getBufferFd(unsigned int index)\n> {\n> \tStream *stream = config_->at(0).stream();\n> \tconst std::vector> &buffers =\n> \t\tbufferAllocator_->buffers(stream);\n> \n> \tif (buffers.size() <= index)\n> -\t\treturn FileDescriptor();\n> +\t\treturn -1;\n> \n> -\treturn buffers[index]->planes()[0].fd;\n> +\treturn buffers[index]->planes()[0].fd.fd();\n> }\n> \n> int V4L2Camera::streamOn()\n> diff --git a/src/v4l2/v4l2_camera.h b/src/v4l2/v4l2_camera.h\n> index d2380462..8efe1642 100644\n> --- a/src/v4l2/v4l2_camera.h\n> +++ b/src/v4l2/v4l2_camera.h\n> @@ -53,7 +53,7 @@ public:\n> \n> \tint allocBuffers(unsigned int count);\n> \tvoid freeBuffers();\n> -\tFileDescriptor getBufferFd(unsigned int index);\n> +\tint getBufferFd(unsigned int index);\n> \n> \tint streamOn();\n> \tint streamOff();\n> diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp\n> index f8bfe595..8f417421 100644\n> --- a/src/v4l2/v4l2_camera_proxy.cpp\n> +++ b/src/v4l2/v4l2_camera_proxy.cpp\n> @@ -112,14 +112,14 @@ void *V4L2CameraProxy::mmap(void *addr, size_t length, int prot, int flags,\n> \t\treturn MAP_FAILED;\n> \t}\n> \n> -\tFileDescriptor fd = vcam_->getBufferFd(index);\n> -\tif (!fd.isValid()) {\n> +\tint fd = vcam_->getBufferFd(index);\n> +\tif (fd < 0) {\n> \t\terrno = EINVAL;\n> \t\treturn MAP_FAILED;\n> \t}\n> \n> \tvoid *map = V4L2CompatManager::instance()->fops().mmap(addr, length, prot,\n> -\t\t\t\t\t\t\t flags, fd.fd(), 0);\n> +\t\t\t\t\t\t\t flags, fd, 0);\n> \tif (map == MAP_FAILED)\n> \t\treturn map;\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 32382C3206\n\tfor ;\n\tSun, 6 Jun 2021 18:56:41 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 9C6356892B;\n\tSun, 6 Jun 2021 20:56:40 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id D0AE3602A7\n\tfor ;\n\tSun, 6 Jun 2021 20:56:39 +0200 (CEST)","from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi\n\t[62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 1B311EF;\n\tSun, 6 Jun 2021 20:56:39 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"uNYqJRVE\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1623005799;\n\tbh=TLeEPz6CAuxZGT8S+O5N3HMFGEig97M+WUfEnknWFLQ=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=uNYqJRVEfhnSsFwXz12XyoClNanXN8LXEV0IIRiwJTgiVnm2HGwQQ+vNi7KDUdfJN\n\tBSazsiX8vvCcb+G/vwmFqB/q387oLSA41vMrNRXaYcosDeJzllUwF0iYyYI2SB0N2z\n\t5q/X7W9zI3J5rFZS0ZiUOFyCDCz0okhEtMShIgl0=","Date":"Sun, 6 Jun 2021 21:56:25 +0300","From":"Laurent Pinchart ","To":"Hirokazu Honda ","Message-ID":"","References":"<20210415083843.3399502-1-hiroh@chromium.org>\n\t<20210415083843.3399502-10-hiroh@chromium.org>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<20210415083843.3399502-10-hiroh@chromium.org>","Subject":"Re: [libcamera-devel] [RFC PATCH 10/10] v4l2: V4L2Camera: Return\n\tint in getBufferFd()","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"libcamera-devel@lists.libcamera.org","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":17435,"web_url":"https://patchwork.libcamera.org/comment/17435/","msgid":"","date":"2021-06-07T09:22:21","subject":"Re: [libcamera-devel] [RFC PATCH 10/10] v4l2: V4L2Camera: Return\n\tint in getBufferFd()","submitter":{"id":63,"url":"https://patchwork.libcamera.org/api/people/63/","name":"Hirokazu Honda","email":"hiroh@chromium.org"},"content":"Hi Laurent,\n\nOn Mon, Jun 7, 2021 at 3:56 AM Laurent Pinchart <\nlaurent.pinchart@ideasonboard.com> wrote:\n\n> Hi Hiro,\n>\n> Thank you for the patch.\n>\n> On Thu, Apr 15, 2021 at 05:38:43PM +0900, Hirokazu Honda wrote:\n> > V4L2Camera::getBufferFd() returns FileDescriptor. However, the\n> > file descriptor is still owned by V4L2Camera. It should rather\n> > return an integer to represent V4L2Camera doesn't have the\n> > ownership of the file descriptor.\n>\n> The FileDescriptor class doesn't imply ownership, as it's similar to a\n> shared_ptr<>. I'm not against this patch, but why do you think\n> FileDescriptor is bad here ?\n>\n>\nIMO, returning FileDescriptor implies that a caller shares the ownership of\nit.\nIt enables a caller to keep it outlive a callee and even share its\nownership with others.\nWhat do you think?\n\n-Hiro\n\n> Signed-off-by: Hirokazu Honda \n> > ---\n> > src/v4l2/v4l2_camera.cpp | 6 +++---\n> > src/v4l2/v4l2_camera.h | 2 +-\n> > src/v4l2/v4l2_camera_proxy.cpp | 6 +++---\n> > 3 files changed, 7 insertions(+), 7 deletions(-)\n> >\n> > diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp\n> > index 97825c71..cccc6749 100644\n> > --- a/src/v4l2/v4l2_camera.cpp\n> > +++ b/src/v4l2/v4l2_camera.cpp\n> > @@ -186,16 +186,16 @@ void V4L2Camera::freeBuffers()\n> > bufferAllocator_->free(stream);\n> > }\n> >\n> > -FileDescriptor V4L2Camera::getBufferFd(unsigned int index)\n> > +int V4L2Camera::getBufferFd(unsigned int index)\n> > {\n> > Stream *stream = config_->at(0).stream();\n> > const std::vector> &buffers =\n> > bufferAllocator_->buffers(stream);\n> >\n> > if (buffers.size() <= index)\n> > - return FileDescriptor();\n> > + return -1;\n> >\n> > - return buffers[index]->planes()[0].fd;\n> > + return buffers[index]->planes()[0].fd.fd();\n> > }\n> >\n> > int V4L2Camera::streamOn()\n> > diff --git a/src/v4l2/v4l2_camera.h b/src/v4l2/v4l2_camera.h\n> > index d2380462..8efe1642 100644\n> > --- a/src/v4l2/v4l2_camera.h\n> > +++ b/src/v4l2/v4l2_camera.h\n> > @@ -53,7 +53,7 @@ public:\n> >\n> > int allocBuffers(unsigned int count);\n> > void freeBuffers();\n> > - FileDescriptor getBufferFd(unsigned int index);\n> > + int getBufferFd(unsigned int index);\n> >\n> > int streamOn();\n> > int streamOff();\n> > diff --git a/src/v4l2/v4l2_camera_proxy.cpp\n> b/src/v4l2/v4l2_camera_proxy.cpp\n> > index f8bfe595..8f417421 100644\n> > --- a/src/v4l2/v4l2_camera_proxy.cpp\n> > +++ b/src/v4l2/v4l2_camera_proxy.cpp\n> > @@ -112,14 +112,14 @@ void *V4L2CameraProxy::mmap(void *addr, size_t\n> length, int prot, int flags,\n> > return MAP_FAILED;\n> > }\n> >\n> > - FileDescriptor fd = vcam_->getBufferFd(index);\n> > - if (!fd.isValid()) {\n> > + int fd = vcam_->getBufferFd(index);\n> > + if (fd < 0) {\n> > errno = EINVAL;\n> > return MAP_FAILED;\n> > }\n> >\n> > void *map = V4L2CompatManager::instance()->fops().mmap(addr,\n> length, prot,\n> > - flags,\n> fd.fd(), 0);\n> > + flags, fd,\n> 0);\n> > if (map == MAP_FAILED)\n> > return map;\n> >\n>\n> --\n> Regards,\n>\n> Laurent Pinchart\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 80F05C3206\n\tfor ;\n\tMon, 7 Jun 2021 09:22:34 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 0477368926;\n\tMon, 7 Jun 2021 11:22:34 +0200 (CEST)","from mail-ed1-x52e.google.com (mail-ed1-x52e.google.com\n\t[IPv6:2a00:1450:4864:20::52e])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 1C14968925\n\tfor ;\n\tMon, 7 Jun 2021 11:22:32 +0200 (CEST)","by mail-ed1-x52e.google.com with SMTP id r11so19420187edt.13\n\tfor ;\n\tMon, 07 Jun 2021 02:22:32 -0700 (PDT)"],"Authentication-Results":"lancelot.ideasonboard.com; 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\n\tMon, 07 Jun 2021 02:22:31 -0700 (PDT)","MIME-Version":"1.0","References":"<20210415083843.3399502-1-hiroh@chromium.org>\n\t<20210415083843.3399502-10-hiroh@chromium.org>\n\t","In-Reply-To":"","From":"Hirokazu Honda ","Date":"Mon, 7 Jun 2021 18:22:21 +0900","Message-ID":"","To":"Laurent Pinchart ","Content-Type":"multipart/alternative; boundary=\"000000000000bd960705c429940d\"","Subject":"Re: [libcamera-devel] [RFC PATCH 10/10] v4l2: V4L2Camera: Return\n\tint in getBufferFd()","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"libcamera devel ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":17841,"web_url":"https://patchwork.libcamera.org/comment/17841/","msgid":"","date":"2021-06-28T03:03:50","subject":"Re: [libcamera-devel] [RFC PATCH 10/10] v4l2: V4L2Camera: Return\n\tint in getBufferFd()","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Hiro,\n\nOn Mon, Jun 07, 2021 at 06:22:21PM +0900, Hirokazu Honda wrote:\n> On Mon, Jun 7, 2021 at 3:56 AM Laurent Pinchart wrote:\n> > On Thu, Apr 15, 2021 at 05:38:43PM +0900, Hirokazu Honda wrote:\n> > > V4L2Camera::getBufferFd() returns FileDescriptor. However, the\n> > > file descriptor is still owned by V4L2Camera. It should rather\n> > > return an integer to represent V4L2Camera doesn't have the\n> > > ownership of the file descriptor.\n> >\n> > The FileDescriptor class doesn't imply ownership, as it's similar to a\n> > shared_ptr<>. I'm not against this patch, but why do you think\n> > FileDescriptor is bad here ?\n>\n> IMO, returning FileDescriptor implies that a caller shares the ownership of it.\n> It enables a caller to keep it outlive a callee and even share its\n> ownership with others.\n> What do you think?\n\nGenerally speaking, it may be dangerous to handle file descriptors as\nintegers, due not only to the risk of leakage, but also to the risk of\nuse-after-free (or rather use-after-close in this case). FileDescriptor\nprevents that.\n\nOn the other hand, I agree with you that in this case the caller isn't\nmeant to use the file descriptor in any way that would outlive the\ndescriptor stored in V4L2Camera. If it was a generic API, I'd prefer\nkeeping FileDescriptor, but as V4L2Camera and V4L2CameraProxy are\ntightly coupled, it really doesn't matter much. I'm OK with the patch if\nyou think it's better.\n\n> > Signed-off-by: Hirokazu Honda \n> > > ---\n> > > src/v4l2/v4l2_camera.cpp | 6 +++---\n> > > src/v4l2/v4l2_camera.h | 2 +-\n> > > src/v4l2/v4l2_camera_proxy.cpp | 6 +++---\n> > > 3 files changed, 7 insertions(+), 7 deletions(-)\n> > >\n> > > diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp\n> > > index 97825c71..cccc6749 100644\n> > > --- a/src/v4l2/v4l2_camera.cpp\n> > > +++ b/src/v4l2/v4l2_camera.cpp\n> > > @@ -186,16 +186,16 @@ void V4L2Camera::freeBuffers()\n> > > bufferAllocator_->free(stream);\n> > > }\n> > >\n> > > -FileDescriptor V4L2Camera::getBufferFd(unsigned int index)\n> > > +int V4L2Camera::getBufferFd(unsigned int index)\n> > > {\n> > > Stream *stream = config_->at(0).stream();\n> > > const std::vector> &buffers =\n> > > bufferAllocator_->buffers(stream);\n> > >\n> > > if (buffers.size() <= index)\n> > > - return FileDescriptor();\n> > > + return -1;\n> > >\n> > > - return buffers[index]->planes()[0].fd;\n> > > + return buffers[index]->planes()[0].fd.fd();\n> > > }\n> > >\n> > > int V4L2Camera::streamOn()\n> > > diff --git a/src/v4l2/v4l2_camera.h b/src/v4l2/v4l2_camera.h\n> > > index d2380462..8efe1642 100644\n> > > --- a/src/v4l2/v4l2_camera.h\n> > > +++ b/src/v4l2/v4l2_camera.h\n> > > @@ -53,7 +53,7 @@ public:\n> > >\n> > > int allocBuffers(unsigned int count);\n> > > void freeBuffers();\n> > > - FileDescriptor getBufferFd(unsigned int index);\n> > > + int getBufferFd(unsigned int index);\n> > >\n> > > int streamOn();\n> > > int streamOff();\n> > > diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp\n> > > index f8bfe595..8f417421 100644\n> > > --- a/src/v4l2/v4l2_camera_proxy.cpp\n> > > +++ b/src/v4l2/v4l2_camera_proxy.cpp\n> > > @@ -112,14 +112,14 @@ void *V4L2CameraProxy::mmap(void *addr, size_t length, int prot, int flags,\n> > > return MAP_FAILED;\n> > > }\n> > >\n> > > - FileDescriptor fd = vcam_->getBufferFd(index);\n> > > - if (!fd.isValid()) {\n> > > + int fd = vcam_->getBufferFd(index);\n> > > + if (fd < 0) {\n> > > errno = EINVAL;\n> > > return MAP_FAILED;\n> > > }\n> > >\n> > > void *map = V4L2CompatManager::instance()->fops().mmap(addr, length, prot,\n> > > - flags, fd.fd(), 0);\n> > > + flags, fd, 0);\n> > > if (map == MAP_FAILED)\n> > > return map;\n> > >","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 2C27FC321D\n\tfor ;\n\tMon, 28 Jun 2021 03:03:54 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 3F214684D7;\n\tMon, 28 Jun 2021 05:03:53 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id AD3116028C\n\tfor ;\n\tMon, 28 Jun 2021 05:03:51 +0200 (CEST)","from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi\n\t[62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 25F4557E;\n\tMon, 28 Jun 2021 05:03:51 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"X4xqNgZ2\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1624849431;\n\tbh=pxswadTq1f+2IgyUTI/2mypO3CdQmwfbUtfwcPJ3g44=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=X4xqNgZ2mo3/EEH1FbiXxG/RJ4cbEeu4pRLCwLXOWV9nW+6n4b4v4xfZB28fvSk0Z\n\tTGQB1euTk8eKXho841Mhfupk2An/rjwyMeqfSYIEdghRRQN7aSIn7SVs8V96hjtWbH\n\tUcZam5gFg0IcFtsl+qCLAdSdfHy1v/gI0Eu5VATU=","Date":"Mon, 28 Jun 2021 06:03:50 +0300","From":"Laurent Pinchart ","To":"Hirokazu Honda ","Message-ID":"","References":"<20210415083843.3399502-1-hiroh@chromium.org>\n\t<20210415083843.3399502-10-hiroh@chromium.org>\n\t\n\t","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"","Subject":"Re: [libcamera-devel] [RFC PATCH 10/10] v4l2: V4L2Camera: Return\n\tint in getBufferFd()","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"libcamera devel ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":17905,"web_url":"https://patchwork.libcamera.org/comment/17905/","msgid":"","date":"2021-06-28T21:11:14","subject":"Re: [libcamera-devel] [RFC PATCH 10/10] v4l2: V4L2Camera: Return\n\tint in getBufferFd()","submitter":{"id":63,"url":"https://patchwork.libcamera.org/api/people/63/","name":"Hirokazu Honda","email":"hiroh@chromium.org"},"content":"Hi Laurent,\n\nOn Mon, Jun 28, 2021 at 12:03 PM Laurent Pinchart\n wrote:\n>\n> Hi Hiro,\n>\n> On Mon, Jun 07, 2021 at 06:22:21PM +0900, Hirokazu Honda wrote:\n> > On Mon, Jun 7, 2021 at 3:56 AM Laurent Pinchart wrote:\n> > > On Thu, Apr 15, 2021 at 05:38:43PM +0900, Hirokazu Honda wrote:\n> > > > V4L2Camera::getBufferFd() returns FileDescriptor. However, the\n> > > > file descriptor is still owned by V4L2Camera. It should rather\n> > > > return an integer to represent V4L2Camera doesn't have the\n> > > > ownership of the file descriptor.\n> > >\n> > > The FileDescriptor class doesn't imply ownership, as it's similar to a\n> > > shared_ptr<>. I'm not against this patch, but why do you think\n> > > FileDescriptor is bad here ?\n> >\n> > IMO, returning FileDescriptor implies that a caller shares the ownership of it.\n> > It enables a caller to keep it outlive a callee and even share its\n> > ownership with others.\n> > What do you think?\n>\n> Generally speaking, it may be dangerous to handle file descriptors as\n> integers, due not only to the risk of leakage, but also to the risk of\n> use-after-free (or rather use-after-close in this case). FileDescriptor\n> prevents that.\n>\n> On the other hand, I agree with you that in this case the caller isn't\n> meant to use the file descriptor in any way that would outlive the\n> descriptor stored in V4L2Camera. If it was a generic API, I'd prefer\n> keeping FileDescriptor, but as V4L2Camera and V4L2CameraProxy are\n> tightly coupled, it really doesn't matter much. I'm OK with the patch if\n> you think it's better.\n>\n\nI would like to keep my idea as the current getBufferFd usage intends\nto not share the ownership.\nIf the usage needs to be changed, I think it will be better to use\nFileDescriptor at that time.\n\nThanks,\n-Hiro\n> > > Signed-off-by: Hirokazu Honda \n> > > > ---\n> > > > src/v4l2/v4l2_camera.cpp | 6 +++---\n> > > > src/v4l2/v4l2_camera.h | 2 +-\n> > > > src/v4l2/v4l2_camera_proxy.cpp | 6 +++---\n> > > > 3 files changed, 7 insertions(+), 7 deletions(-)\n> > > >\n> > > > diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp\n> > > > index 97825c71..cccc6749 100644\n> > > > --- a/src/v4l2/v4l2_camera.cpp\n> > > > +++ b/src/v4l2/v4l2_camera.cpp\n> > > > @@ -186,16 +186,16 @@ void V4L2Camera::freeBuffers()\n> > > > bufferAllocator_->free(stream);\n> > > > }\n> > > >\n> > > > -FileDescriptor V4L2Camera::getBufferFd(unsigned int index)\n> > > > +int V4L2Camera::getBufferFd(unsigned int index)\n> > > > {\n> > > > Stream *stream = config_->at(0).stream();\n> > > > const std::vector> &buffers =\n> > > > bufferAllocator_->buffers(stream);\n> > > >\n> > > > if (buffers.size() <= index)\n> > > > - return FileDescriptor();\n> > > > + return -1;\n> > > >\n> > > > - return buffers[index]->planes()[0].fd;\n> > > > + return buffers[index]->planes()[0].fd.fd();\n> > > > }\n> > > >\n> > > > int V4L2Camera::streamOn()\n> > > > diff --git a/src/v4l2/v4l2_camera.h b/src/v4l2/v4l2_camera.h\n> > > > index d2380462..8efe1642 100644\n> > > > --- a/src/v4l2/v4l2_camera.h\n> > > > +++ b/src/v4l2/v4l2_camera.h\n> > > > @@ -53,7 +53,7 @@ public:\n> > > >\n> > > > int allocBuffers(unsigned int count);\n> > > > void freeBuffers();\n> > > > - FileDescriptor getBufferFd(unsigned int index);\n> > > > + int getBufferFd(unsigned int index);\n> > > >\n> > > > int streamOn();\n> > > > int streamOff();\n> > > > diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp\n> > > > index f8bfe595..8f417421 100644\n> > > > --- a/src/v4l2/v4l2_camera_proxy.cpp\n> > > > +++ b/src/v4l2/v4l2_camera_proxy.cpp\n> > > > @@ -112,14 +112,14 @@ void *V4L2CameraProxy::mmap(void *addr, size_t length, int prot, int flags,\n> > > > return MAP_FAILED;\n> > > > }\n> > > >\n> > > > - FileDescriptor fd = vcam_->getBufferFd(index);\n> > > > - if (!fd.isValid()) {\n> > > > + int fd = vcam_->getBufferFd(index);\n> > > > + if (fd < 0) {\n> > > > errno = EINVAL;\n> > > > return MAP_FAILED;\n> > > > }\n> > > >\n> > > > void *map = V4L2CompatManager::instance()->fops().mmap(addr, length, prot,\n> > > > - flags, fd.fd(), 0);\n> > > > + flags, fd, 0);\n> > > > if (map == MAP_FAILED)\n> > > > return map;\n> > > >\n>\n> --\n> Regards,\n>\n> Laurent Pinchart","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 2F290C321F\n\tfor ;\n\tMon, 28 Jun 2021 21:11:27 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 704A2684D8;\n\tMon, 28 Jun 2021 23:11:26 +0200 (CEST)","from mail-ed1-x532.google.com (mail-ed1-x532.google.com\n\t[IPv6:2a00:1450:4864:20::532])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 2382C6028C\n\tfor ;\n\tMon, 28 Jun 2021 23:11:25 +0200 (CEST)","by mail-ed1-x532.google.com with SMTP id df12so28083621edb.2\n\tfor ;\n\tMon, 28 Jun 2021 14:11:25 -0700 (PDT)"],"Authentication-Results":"lancelot.ideasonboard.com; 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\n\tMon, 28 Jun 2021 14:11:24 -0700 (PDT)","MIME-Version":"1.0","References":"<20210415083843.3399502-1-hiroh@chromium.org>\n\t<20210415083843.3399502-10-hiroh@chromium.org>\n\t\n\t\n\t","In-Reply-To":"","From":"Hirokazu Honda ","Date":"Tue, 29 Jun 2021 06:11:14 +0900","Message-ID":"","To":"Laurent Pinchart ","Content-Type":"text/plain; charset=\"UTF-8\"","Subject":"Re: [libcamera-devel] [RFC PATCH 10/10] v4l2: V4L2Camera: Return\n\tint in getBufferFd()","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"libcamera devel ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]