[{"id":28671,"web_url":"https://patchwork.libcamera.org/comment/28671/","msgid":"<87plwxdfcu.fsf@redhat.com>","date":"2024-02-15T13:30:41","subject":"Re: [PATCH v3 05/16] libcamera: shared_mem_object: reorganize the\n\tcode and document the SharedMemObject class","submitter":{"id":177,"url":"https://patchwork.libcamera.org/api/people/177/","name":"Milan Zamazal","email":"mzamazal@redhat.com"},"content":"Hans de Goede writes:\n\n> From: Andrei Konovalov \n>\n> Split the parts which doesn't otherwise depend on the type T or\n> arguments Args out of the SharedMemObject class into a new\n> SharedMem class.\n>\n> Doxygen documentation by Dennis Bonke and Andrei Konovalov.\n>\n> Reviewed-by: Pavel Machek \n> Co-developed-by: Dennis Bonke \n> Signed-off-by: Dennis Bonke \n> Signed-off-by: Andrei Konovalov \n> ---\n> .../libcamera/internal/shared_mem_object.h | 92 ++++++---\n> src/libcamera/meson.build | 1 +\n> src/libcamera/shared_mem_object.cpp | 191 ++++++++++++++++++\n> 3 files changed, 253 insertions(+), 31 deletions(-)\n> create mode 100644 src/libcamera/shared_mem_object.cpp\n>\n> diff --git a/include/libcamera/internal/shared_mem_object.h b/include/libcamera/internal/shared_mem_object.h\n> index bfb639ee..a4de6500 100644\n> --- a/include/libcamera/internal/shared_mem_object.h\n> +++ b/include/libcamera/internal/shared_mem_object.h\n> @@ -7,11 +7,8 @@\n> #pragma once\n> \n> #include \n> -#include \n> #include \n> #include \n> -#include \n> -#include \n> #include \n> \n> #include \n> @@ -19,6 +16,59 @@\n> \n> namespace libcamera {\n> \n> +class SharedMem\n> +{\n> +public:\n> +\tSharedMem()\n> +\t\t: mem_(nullptr)\n> +\t{\n> +\t}\n> +\n> +\tSharedMem(const std::string &name, std::size_t size);\n> +\n> +\tSharedMem(SharedMem &&rhs)\n> +\t{\n> +\t\tthis->name_ = std::move(rhs.name_);\n> +\t\tthis->fd_ = std::move(rhs.fd_);\n> +\t\tthis->mem_ = rhs.mem_;\n> +\t\trhs.mem_ = nullptr;\n> +\t}\n> +\n> +\t~SharedMem()\n> +\t{\n> +\t\tif (mem_)\n> +\t\t\tmunmap(mem_, size_);\n> +\t}\n> +\n> +\t/* Make SharedMem non-copyable for now. */\n> +\tLIBCAMERA_DISABLE_COPY(SharedMem)\n> +\n> +\tSharedMem &operator=(SharedMem &&rhs)\n> +\t{\n> +\t\tthis->name_ = std::move(rhs.name_);\n> +\t\tthis->fd_ = std::move(rhs.fd_);\n> +\t\tthis->mem_ = rhs.mem_;\n> +\t\trhs.mem_ = nullptr;\n> +\t\treturn *this;\n> +\t}\n> +\n> +\tconst SharedFD &fd() const\n> +\t{\n> +\t\treturn fd_;\n> +\t}\n> +\n> +\tvoid *mem() const\n> +\t{\n> +\t\treturn mem_;\n> +\t}\n> +\n> +private:\n> +\tstd::string name_;\n> +\tSharedFD fd_;\n> +\tsize_t size_;\n> +\tvoid *mem_;\n> +};\n> +\n> template\n> class SharedMemObject\n> {\n> @@ -32,26 +82,11 @@ public:\n> \n> \ttemplate\n> \tSharedMemObject(const std::string &name, Args &&...args)\n> -\t\t: name_(name), obj_(nullptr)\n> +\t\t: shMem_(name, SIZE), obj_(nullptr)\n> \t{\n> -\t\tvoid *mem;\n> -\t\tint ret;\n> +\t\tvoid *mem = shMem_.mem();\n> \n> -\t\tret = memfd_create(name_.c_str(), MFD_CLOEXEC);\n> -\t\tif (ret < 0)\n> -\t\t\treturn;\n> -\n> -\t\tfd_ = SharedFD(std::move(ret));\n> -\t\tif (!fd_.isValid())\n> -\t\t\treturn;\n> -\n> -\t\tret = ftruncate(fd_.get(), SIZE);\n> -\t\tif (ret < 0)\n> -\t\t\treturn;\n> -\n> -\t\tmem = mmap(nullptr, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,\n> -\t\t\t fd_.get(), 0);\n> -\t\tif (mem == MAP_FAILED)\n> +\t\tif (mem == nullptr)\n> \t\t\treturn;\n> \n> \t\tobj_ = new (mem) T(std::forward(args)...);\n> @@ -59,18 +94,15 @@ public:\n> \n> \tSharedMemObject(SharedMemObject &&rhs)\n> \t{\n> -\t\tthis->name_ = std::move(rhs.name_);\n> -\t\tthis->fd_ = std::move(rhs.fd_);\n> +\t\tthis->shMem_ = std::move(rhs.shMem_);\n> \t\tthis->obj_ = rhs.obj_;\n> \t\trhs.obj_ = nullptr;\n> \t}\n> \n> \t~SharedMemObject()\n> \t{\n> -\t\tif (obj_) {\n> +\t\tif (obj_)\n> \t\t\tobj_->~T();\n> -\t\t\tmunmap(obj_, SIZE);\n> -\t\t}\n> \t}\n> \n> \t/* Make SharedMemObject non-copyable for now. */\n> @@ -78,8 +110,7 @@ public:\n> \n> \tSharedMemObject &operator=(SharedMemObject &&rhs)\n> \t{\n> -\t\tthis->name_ = std::move(rhs.name_);\n> -\t\tthis->fd_ = std::move(rhs.fd_);\n> +\t\tthis->shMem_ = std::move(rhs.shMem_);\n> \t\tthis->obj_ = rhs.obj_;\n> \t\trhs.obj_ = nullptr;\n> \t\treturn *this;\n> @@ -107,7 +138,7 @@ public:\n> \n> \tconst SharedFD &fd() const\n> \t{\n> -\t\treturn fd_;\n> +\t\treturn shMem_.fd();\n> \t}\n> \n> \texplicit operator bool() const\n> @@ -116,8 +147,7 @@ public:\n> \t}\n> \n> private:\n> -\tstd::string name_;\n> -\tSharedFD fd_;\n> +\tSharedMem shMem_;\n> \tT *obj_;\n> };\n> \n> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build\n> index 3c5e43df..94a95ae3 100644\n> --- a/src/libcamera/meson.build\n> +++ b/src/libcamera/meson.build\n> @@ -41,6 +41,7 @@ libcamera_sources = files([\n> 'process.cpp',\n> 'pub_key.cpp',\n> 'request.cpp',\n> + 'shared_mem_object.cpp',\n> 'source_paths.cpp',\n> 'stream.cpp',\n> 'sysfs.cpp',\n> diff --git a/src/libcamera/shared_mem_object.cpp b/src/libcamera/shared_mem_object.cpp\n> new file mode 100644\n> index 00000000..06bbee38\n> --- /dev/null\n> +++ b/src/libcamera/shared_mem_object.cpp\n> @@ -0,0 +1,191 @@\n> +/* SPDX-License-Identifier: LGPL-2.1-or-later */\n> +/*\n> + * Copyright (C) 2023, Raspberry Pi Ltd\n> + *\n> + * shared_mem_object.cpp - Helper class for shared memory allocations\n> + */\n> +\n> +#include \"libcamera/internal/shared_mem_object.h\"\n> +\n> +#include \n> +#include \n> +\n> +/**\n> + * \\file shared_mem_object.cpp\n> + * \\brief Helper class for shared memory allocations\n> + */\n> +\n> +namespace libcamera {\n> +\n> +/**\n> + * \\class SharedMem\n> + * \\brief Helper class for allocating shared memory\n> + *\n> + * Memory is allocated and exposed as a SharedFD for use across IPC boundaries.\n> + *\n> + * SharedMem allocates the shared memory of the given size and maps it.\n> + * To check that the shared memory was allocated and mapped successfully, one\n> + * needs to verify that the pointer to the shared memory returned by SharedMem::mem()\n> + * is not nullptr.\n> + *\n> + * To access the shared memory from another process the SharedFD should be passed\n> + * to that process, and then the shared memory should be mapped into that process\n> + * address space by calling mmap().\n> + *\n> + * A single memfd is created for every SharedMem. If there is a need to allocate\n> + * a large number of objects in shared memory, these objects should be grouped\n> + * together and use the shared memory allocated by a single SharedMem object if\n> + * possible. This will help to minimize the number of created memfd's.\n> + */\n> +\n> +/**\n> + * \\fn SharedMem::SharedMem(const std::string &name, std::size_t size)\n> + * \\brief Contstructor for the SharedMem\n> + * \\param[in] name Name of the SharedMem\n> + * \\param[in] size Size of the shared memory to allocate and map\n> + */\n> +\n> +/**\n> + * \\fn SharedMem::SharedMem(SharedMem &&rhs)\n> + * \\brief Move constructor for SharedMem\n> + * \\param[in] rhs The object to move\n> + */\n> +\n> +/**\n> + * \\fn SharedMem::~SharedMem()\n> + * \\brief SharedMem destructor\n> + *\n> + * Unmaps the allocated shared memory. Decrements the shared memory descriptor use\n> + * count.\n> + */\n> +\n> +/**\n> + * \\fn SharedMem &SharedMem::operator=(SharedMem &&rhs)\n> + * \\brief Move constructor for SharedMem\n> + * \\param[in] rhs The object to move\n> + */\n> +\n> +/**\n> + * \\fn const SharedFD &SharedMem::fd() const\n> + * \\brief Gets the file descriptor for the underlaying shared memory\n> + * \\return The file descriptor\n> + */\n> +\n> +/**\n> + * \\fn void *SharedMem::mem() const\n> + * \\brief Gets the pointer to the underlaying shared memory\n> + * \\return The pointer to the shared memory\n> + */\n> +\n> +SharedMem::SharedMem(const std::string &name, std::size_t size)\n> +\t: name_(name), size_(size), mem_(nullptr)\n> +{\n> +\tint fd = memfd_create(name_.c_str(), MFD_CLOEXEC);\n> +\tif (fd < 0)\n> +\t\treturn;\n> +\n> +\tfd_ = SharedFD(std::move(fd));\n> +\tif (!fd_.isValid())\n> +\t\treturn;\n> +\n> +\tif (ftruncate(fd_.get(), size_) < 0)\n> +\t\treturn;\n> +\n> +\tmem_ = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED,\n> +\t\t fd_.get(), 0);\n> +\tif (mem_ == MAP_FAILED)\n> +\t\tmem_ = nullptr;\n> +}\n> +\n> +/**\n> + * \\class SharedMemObject\n> + * \\brief Helper class for allocating objects in shared memory\n> + *\n> + * Memory is allocated and exposed as a SharedFD for use across IPC boundaries.\n> + *\n> + * Given the type of the object to be created in shared memory and the arguments\n> + * to pass to this object's constructor, SharedMemObject allocates the shared memory\n> + * of the size of the object and constructs the object in this memory. To check that\n> + * the SharedMemObject was created successfully, one needs to verify that the\n> + * underlying SharedFD (the reference to it is returned by SharedMemObject::fd() member\n> + * function) is valid. The object created in the shared memory can be accessed using\n> + * the SharedMemObject::operator*() indirection operator. Its members can be accessed\n> + * with the SharedMemObject::operator->() member of pointer operator.\n\nBut it can still happen that SharedMemObject::fd() is all right but the object\nreturned from the operators is nullptr, right? It would be good to clarify this\nand refer to the bool operator here.\n\n> \n> + *\n> + * To access the object from another process the SharedFD should be passed to that\n> + * process, and the shared memory should be mapped by calling mmap().\n> + *\n> + * A single memfd is created for every SharedMemObject. If there is a need to allocate\n> + * a large number of objects in shared memory, these objects should be grouped into a\n> + * single large object to keep the number of created memfd's reasonably small.\n> + */\n> +\n> +/**\n> + * \\var SharedMemObject::SIZE\n> + * \\brief The size of the object that is going to be stored here\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject< T >::SharedMemObject(const std::string &name, Args &&...args)\n> + * \\brief Contstructor for the SharedMemObject\n ^^^^^^^^^^^^\n\nConstructor\n\n> + * \\param[in] name Name of the SharedMemObject\n> + * \\param[in] args Args to pass to the constructor of the object in shared memory\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::SharedMemObject(SharedMemObject &&rhs)\n> + * \\brief Move constructor for SharedMemObject\n> + * \\param[in] rhs The object to move\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::~SharedMemObject()\n> + * \\brief SharedMemObject destructor\n> + *\n> + * Destroys the object created in the shared memory and then unmaps the shared memory.\n> + * Decrements the shared memory descriptor use count.\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::operator=(SharedMemObject &&rhs)\n> + * \\brief Operator= for SharedMemObject\n> + * \\param[in] rhs The SharedMemObject object to take the data from\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::operator->()\n> + * \\brief Operator-> for SharedMemObject\n> + * \\return The pointer to the object\n> + */\n> +\n> +/**\n> + * \\fn const T *SharedMemObject::operator->() const\n> + * \\brief Operator-> for SharedMemObject\n> + * \\return The pointer to the const object\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::operator*()\n> + * \\brief Operator* for SharedMemObject\n> + * \\return The reference to the object\n> + */\n> +\n> +/**\n> + * \\fn const T &SharedMemObject::operator*() const\n> + * \\brief Operator* for SharedMemObject\n> + * \\return Const reference to the object\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::fd()\n> + * \\brief Gets the file descriptor for the underlaying storage file\n> + * \\return The shared memory file descriptor (as SharedFD)\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::operator bool()\n> + * \\brief Operator bool() for SharedMemObject\n> + * \\return True if the object was created OK in the shared memory, false otherwise\n> + */\n> +\n> +} // namespace libcamera","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 B67F7BDE17\n\tfor ;\n\tThu, 15 Feb 2024 13:30:48 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 2744562805;\n\tThu, 15 Feb 2024 14:30:48 +0100 (CET)","from us-smtp-delivery-124.mimecast.com\n\t(us-smtp-delivery-124.mimecast.com [170.10.133.124])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 93FA461CB0\n\tfor ;\n\tThu, 15 Feb 2024 14:30:46 +0100 (CET)","from mail-wm1-f72.google.com (mail-wm1-f72.google.com\n\t[209.85.128.72]) by relay.mimecast.com with ESMTP with STARTTLS\n\t(version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id\n\tus-mta-184-G_pIg4JRPVexXeULB3JuSg-1; Thu, 15 Feb 2024 08:30:44 -0500","by mail-wm1-f72.google.com with SMTP id\n\t5b1f17b1804b1-410dfd0e1caso4730695e9.0\n\tfor ;\n\tThu, 15 Feb 2024 05:30:44 -0800 (PST)","from nuthatch (nat-pool-brq-t.redhat.com. 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-0800 (PST)","by 2002:a05:600c:260e:b0:410:6a8b:6937 with SMTP id\n\th14-20020a05600c260e00b004106a8b6937mr1460922wma.37.1708003842587; \n\tThu, 15 Feb 2024 05:30:42 -0800 (PST)"],"X-Google-Smtp-Source":"AGHT+IFLWl4jkRBUZy+s7rVngEcb3gesz1el5/8ei+NeU4KrCWDlokvkd3vYD2MfhXBdVyTuNpshZg==","From":"Milan Zamazal ","To":"Hans de Goede ","Subject":"Re: [PATCH v3 05/16] libcamera: shared_mem_object: reorganize the\n\tcode and document the SharedMemObject class","In-Reply-To":"<20240214170122.60754-6-hdegoede@redhat.com> (Hans de Goede's\n\tmessage of \"Wed, 14 Feb 2024 18:01:09 +0100\")","References":"<20240214170122.60754-1-hdegoede@redhat.com>\n\t<20240214170122.60754-6-hdegoede@redhat.com>","Date":"Thu, 15 Feb 2024 14:30:41 +0100","Message-ID":"<87plwxdfcu.fsf@redhat.com>","User-Agent":"Gnus/5.13 (Gnus v5.13)","MIME-Version":"1.0","X-Mimecast-Spam-Score":"0","X-Mimecast-Originator":"redhat.com","Content-Type":"text/plain","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":"Maxime Ripard , libcamera-devel@lists.libcamera.org, \n\tPavel Machek ,\n\tBryan O'Donoghue , \n\tDennis Bonke ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":28672,"web_url":"https://patchwork.libcamera.org/comment/28672/","msgid":"","date":"2024-02-15T13:39:09","subject":"Re: [PATCH v3 05/16] libcamera: shared_mem_object: reorganize the\n\tcode and document the SharedMemObject class","submitter":{"id":34,"url":"https://patchwork.libcamera.org/api/people/34/","name":"Naushir Patuck","email":"naush@raspberrypi.com"},"content":"Hi Hans,\n\nOn Wed, 14 Feb 2024 at 17:01, Hans de Goede wrote:\n>\n> From: Andrei Konovalov \n>\n> Split the parts which doesn't otherwise depend on the type T or\n> arguments Args out of the SharedMemObject class into a new\n> SharedMem class.\n>\n> Doxygen documentation by Dennis Bonke and Andrei Konovalov.\n>\n> Reviewed-by: Pavel Machek \n> Co-developed-by: Dennis Bonke \n> Signed-off-by: Dennis Bonke \n> Signed-off-by: Andrei Konovalov \n> ---\n> .../libcamera/internal/shared_mem_object.h | 92 ++++++---\n> src/libcamera/meson.build | 1 +\n> src/libcamera/shared_mem_object.cpp | 191 ++++++++++++++++++\n> 3 files changed, 253 insertions(+), 31 deletions(-)\n> create mode 100644 src/libcamera/shared_mem_object.cpp\n>\n> diff --git a/include/libcamera/internal/shared_mem_object.h b/include/libcamera/internal/shared_mem_object.h\n> index bfb639ee..a4de6500 100644\n> --- a/include/libcamera/internal/shared_mem_object.h\n> +++ b/include/libcamera/internal/shared_mem_object.h\n> @@ -7,11 +7,8 @@\n> #pragma once\n>\n> #include \n> -#include \n> #include \n> #include \n> -#include \n> -#include \n> #include \n>\n> #include \n> @@ -19,6 +16,59 @@\n>\n> namespace libcamera {\n>\n> +class SharedMem\n> +{\n> +public:\n> + SharedMem()\n> + : mem_(nullptr)\n> + {\n> + }\n> +\n> + SharedMem(const std::string &name, std::size_t size);\n> +\n> + SharedMem(SharedMem &&rhs)\n> + {\n> + this->name_ = std::move(rhs.name_);\n> + this->fd_ = std::move(rhs.fd_);\n> + this->mem_ = rhs.mem_;\n> + rhs.mem_ = nullptr;\n> + }\n> +\n> + ~SharedMem()\n> + {\n> + if (mem_)\n> + munmap(mem_, size_);\n> + }\n> +\n> + /* Make SharedMem non-copyable for now. */\n> + LIBCAMERA_DISABLE_COPY(SharedMem)\n> +\n> + SharedMem &operator=(SharedMem &&rhs)\n> + {\n> + this->name_ = std::move(rhs.name_);\n> + this->fd_ = std::move(rhs.fd_);\n> + this->mem_ = rhs.mem_;\n> + rhs.mem_ = nullptr;\n> + return *this;\n> + }\n> +\n> + const SharedFD &fd() const\n> + {\n> + return fd_;\n> + }\n> +\n> + void *mem() const\n> + {\n> + return mem_;\n> + }\n> +\n> +private:\n> + std::string name_;\n> + SharedFD fd_;\n> + size_t size_;\n> + void *mem_;\n> +};\n> +\n> template\n> class SharedMemObject\n\nWould it make sense to have SharedMemObject derived from SharedMem?\nThen you would only need a constructor and destructor implemented for\nSharedMemObject, and all other accessors can be through the base\nclass... i think?\n\n> {\n> @@ -32,26 +82,11 @@ public:\n>\n> template\n> SharedMemObject(const std::string &name, Args &&...args)\n> - : name_(name), obj_(nullptr)\n> + : shMem_(name, SIZE), obj_(nullptr)\n> {\n> - void *mem;\n> - int ret;\n> + void *mem = shMem_.mem();\n>\n> - ret = memfd_create(name_.c_str(), MFD_CLOEXEC);\n> - if (ret < 0)\n> - return;\n> -\n> - fd_ = SharedFD(std::move(ret));\n> - if (!fd_.isValid())\n> - return;\n> -\n> - ret = ftruncate(fd_.get(), SIZE);\n> - if (ret < 0)\n> - return;\n> -\n> - mem = mmap(nullptr, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,\n> - fd_.get(), 0);\n> - if (mem == MAP_FAILED)\n> + if (mem == nullptr)\n> return;\n>\n> obj_ = new (mem) T(std::forward(args)...);\n> @@ -59,18 +94,15 @@ public:\n>\n> SharedMemObject(SharedMemObject &&rhs)\n> {\n> - this->name_ = std::move(rhs.name_);\n> - this->fd_ = std::move(rhs.fd_);\n> + this->shMem_ = std::move(rhs.shMem_);\n> this->obj_ = rhs.obj_;\n> rhs.obj_ = nullptr;\n> }\n>\n> ~SharedMemObject()\n> {\n> - if (obj_) {\n> + if (obj_)\n> obj_->~T();\n> - munmap(obj_, SIZE);\n> - }\n> }\n>\n> /* Make SharedMemObject non-copyable for now. */\n> @@ -78,8 +110,7 @@ public:\n>\n> SharedMemObject &operator=(SharedMemObject &&rhs)\n> {\n> - this->name_ = std::move(rhs.name_);\n> - this->fd_ = std::move(rhs.fd_);\n> + this->shMem_ = std::move(rhs.shMem_);\n> this->obj_ = rhs.obj_;\n> rhs.obj_ = nullptr;\n> return *this;\n> @@ -107,7 +138,7 @@ public:\n>\n> const SharedFD &fd() const\n> {\n> - return fd_;\n> + return shMem_.fd();\n> }\n>\n> explicit operator bool() const\n> @@ -116,8 +147,7 @@ public:\n> }\n>\n> private:\n> - std::string name_;\n> - SharedFD fd_;\n> + SharedMem shMem_;\n> T *obj_;\n> };\n>\n> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build\n> index 3c5e43df..94a95ae3 100644\n> --- a/src/libcamera/meson.build\n> +++ b/src/libcamera/meson.build\n> @@ -41,6 +41,7 @@ libcamera_sources = files([\n> 'process.cpp',\n> 'pub_key.cpp',\n> 'request.cpp',\n> + 'shared_mem_object.cpp',\n> 'source_paths.cpp',\n> 'stream.cpp',\n> 'sysfs.cpp',\n> diff --git a/src/libcamera/shared_mem_object.cpp b/src/libcamera/shared_mem_object.cpp\n> new file mode 100644\n> index 00000000..06bbee38\n> --- /dev/null\n> +++ b/src/libcamera/shared_mem_object.cpp\n> @@ -0,0 +1,191 @@\n> +/* SPDX-License-Identifier: LGPL-2.1-or-later */\n> +/*\n> + * Copyright (C) 2023, Raspberry Pi Ltd\n> + *\n> + * shared_mem_object.cpp - Helper class for shared memory allocations\n> + */\n> +\n> +#include \"libcamera/internal/shared_mem_object.h\"\n> +\n> +#include \n> +#include \n> +\n> +/**\n> + * \\file shared_mem_object.cpp\n> + * \\brief Helper class for shared memory allocations\n> + */\n> +\n> +namespace libcamera {\n> +\n> +/**\n> + * \\class SharedMem\n> + * \\brief Helper class for allocating shared memory\n> + *\n> + * Memory is allocated and exposed as a SharedFD for use across IPC boundaries.\n> + *\n> + * SharedMem allocates the shared memory of the given size and maps it.\n> + * To check that the shared memory was allocated and mapped successfully, one\n> + * needs to verify that the pointer to the shared memory returned by SharedMem::mem()\n> + * is not nullptr.\n> + *\n> + * To access the shared memory from another process the SharedFD should be passed\n> + * to that process, and then the shared memory should be mapped into that process\n> + * address space by calling mmap().\n> + *\n> + * A single memfd is created for every SharedMem. If there is a need to allocate\n> + * a large number of objects in shared memory, these objects should be grouped\n> + * together and use the shared memory allocated by a single SharedMem object if\n> + * possible. This will help to minimize the number of created memfd's.\n> + */\n> +\n> +/**\n> + * \\fn SharedMem::SharedMem(const std::string &name, std::size_t size)\n> + * \\brief Contstructor for the SharedMem\n\ns/Contstructor/Constructor/\n\n> + * \\param[in] name Name of the SharedMem\n> + * \\param[in] size Size of the shared memory to allocate and map\n> + */\n> +\n> +/**\n> + * \\fn SharedMem::SharedMem(SharedMem &&rhs)\n> + * \\brief Move constructor for SharedMem\n> + * \\param[in] rhs The object to move\n> + */\n> +\n> +/**\n> + * \\fn SharedMem::~SharedMem()\n> + * \\brief SharedMem destructor\n> + *\n> + * Unmaps the allocated shared memory. Decrements the shared memory descriptor use\n> + * count.\n> + */\n> +\n> +/**\n> + * \\fn SharedMem &SharedMem::operator=(SharedMem &&rhs)\n> + * \\brief Move constructor for SharedMem\n> + * \\param[in] rhs The object to move\n> + */\n> +\n> +/**\n> + * \\fn const SharedFD &SharedMem::fd() const\n> + * \\brief Gets the file descriptor for the underlaying shared memory\n\ns/underlaying/underlying/?\n\n> + * \\return The file descriptor\n> + */\n> +\n> +/**\n> + * \\fn void *SharedMem::mem() const\n> + * \\brief Gets the pointer to the underlaying shared memory\n\ns/underlaying/underlying/?\n\n> + * \\return The pointer to the shared memory\n> + */\n> +\n> +SharedMem::SharedMem(const std::string &name, std::size_t size)\n> + : name_(name), size_(size), mem_(nullptr)\n> +{\n> + int fd = memfd_create(name_.c_str(), MFD_CLOEXEC);\n> + if (fd < 0)\n> + return;\n> +\n> + fd_ = SharedFD(std::move(fd));\n> + if (!fd_.isValid())\n> + return;\n> +\n> + if (ftruncate(fd_.get(), size_) < 0)\n> + return;\n> +\n> + mem_ = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED,\n> + fd_.get(), 0);\n> + if (mem_ == MAP_FAILED)\n> + mem_ = nullptr;\n> +}\n> +\n> +/**\n> + * \\class SharedMemObject\n> + * \\brief Helper class for allocating objects in shared memory\n> + *\n> + * Memory is allocated and exposed as a SharedFD for use across IPC boundaries.\n> + *\n> + * Given the type of the object to be created in shared memory and the arguments\n> + * to pass to this object's constructor, SharedMemObject allocates the shared memory\n> + * of the size of the object and constructs the object in this memory. To check that\n> + * the SharedMemObject was created successfully, one needs to verify that the\n> + * underlying SharedFD (the reference to it is returned by SharedMemObject::fd() member\n> + * function) is valid. The object created in the shared memory can be accessed using\n> + * the SharedMemObject::operator*() indirection operator. Its members can be accessed\n> + * with the SharedMemObject::operator->() member of pointer operator.\n> + *\n> + * To access the object from another process the SharedFD should be passed to that\n> + * process, and the shared memory should be mapped by calling mmap().\n> + *\n> + * A single memfd is created for every SharedMemObject. If there is a need to allocate\n> + * a large number of objects in shared memory, these objects should be grouped into a\n> + * single large object to keep the number of created memfd's reasonably small.\n> + */\n> +\n> +/**\n> + * \\var SharedMemObject::SIZE\n> + * \\brief The size of the object that is going to be stored here\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject< T >::SharedMemObject(const std::string &name, Args &&...args)\n> + * \\brief Contstructor for the SharedMemObject\n\ns/Contstructor/Constructor/\n\n> + * \\param[in] name Name of the SharedMemObject\n> + * \\param[in] args Args to pass to the constructor of the object in shared memory\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::SharedMemObject(SharedMemObject &&rhs)\n> + * \\brief Move constructor for SharedMemObject\n> + * \\param[in] rhs The object to move\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::~SharedMemObject()\n> + * \\brief SharedMemObject destructor\n> + *\n> + * Destroys the object created in the shared memory and then unmaps the shared memory.\n> + * Decrements the shared memory descriptor use count.\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::operator=(SharedMemObject &&rhs)\n> + * \\brief Operator= for SharedMemObject\n> + * \\param[in] rhs The SharedMemObject object to take the data from\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::operator->()\n> + * \\brief Operator-> for SharedMemObject\n> + * \\return The pointer to the object\n> + */\n> +\n> +/**\n> + * \\fn const T *SharedMemObject::operator->() const\n> + * \\brief Operator-> for SharedMemObject\n> + * \\return The pointer to the const object\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::operator*()\n> + * \\brief Operator* for SharedMemObject\n> + * \\return The reference to the object\n> + */\n> +\n> +/**\n> + * \\fn const T &SharedMemObject::operator*() const\n> + * \\brief Operator* for SharedMemObject\n> + * \\return Const reference to the object\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::fd()\n> + * \\brief Gets the file descriptor for the underlaying storage file\n\ns/underlaying/underlying/\n\nThanks,\nNaush\n\n\n> + * \\return The shared memory file descriptor (as SharedFD)\n> + */\n> +\n> +/**\n> + * \\fn SharedMemObject::operator bool()\n> + * \\brief Operator bool() for SharedMemObject\n> + * \\return True if the object was created OK in the shared memory, false otherwise\n> + */\n> +\n> +} // namespace libcamera\n> --\n> 2.43.0\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 2CACFC3257\n\tfor ;\n\tThu, 15 Feb 2024 13:39:49 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 619F562805;\n\tThu, 15 Feb 2024 14:39:48 +0100 (CET)","from 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id\n\tx7-20020a25b907000000b00dc75a73184emr1591405ybj.14.1708004384703;\n\tThu, 15 Feb 2024 05:39:44 -0800 (PST)","MIME-Version":"1.0","References":"<20240214170122.60754-1-hdegoede@redhat.com>\n\t<20240214170122.60754-6-hdegoede@redhat.com>","In-Reply-To":"<20240214170122.60754-6-hdegoede@redhat.com>","From":"Naushir Patuck ","Date":"Thu, 15 Feb 2024 13:39:09 +0000","Message-ID":"","Subject":"Re: [PATCH v3 05/16] libcamera: shared_mem_object: reorganize the\n\tcode and document the SharedMemObject class","To":"Hans de Goede ","Content-Type":"text/plain; charset=\"UTF-8\"","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":"Bryan O'Donoghue ,\n\tlibcamera-devel@lists.libcamera.org, Maxime Ripard , \n\tPavel Machek , Dennis Bonke ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":28692,"web_url":"https://patchwork.libcamera.org/comment/28692/","msgid":"","date":"2024-02-18T19:22:54","subject":"Re: [PATCH v3 05/16] libcamera: shared_mem_object: reorganize the\n\tcode and document the SharedMemObject class","submitter":{"id":179,"url":"https://patchwork.libcamera.org/api/people/179/","name":"Andrei Konovalov","email":"andrey.konovalov.ynk@gmail.com"},"content":"Hi Milan,\n\nThank you for the review!\n\nOn 15.02.2024 16:30, Milan Zamazal wrote:\n> Hans de Goede writes:\n> \n>> From: Andrei Konovalov \n>>\n>> Split the parts which doesn't otherwise depend on the type T or\n>> arguments Args out of the SharedMemObject class into a new\n>> SharedMem class.\n>>\n>> Doxygen documentation by Dennis Bonke and Andrei Konovalov.\n>>\n>> Reviewed-by: Pavel Machek \n>> Co-developed-by: Dennis Bonke \n>> Signed-off-by: Dennis Bonke \n>> Signed-off-by: Andrei Konovalov \n>> ---\n>> .../libcamera/internal/shared_mem_object.h | 92 ++++++---\n>> src/libcamera/meson.build | 1 +\n>> src/libcamera/shared_mem_object.cpp | 191 ++++++++++++++++++\n>> 3 files changed, 253 insertions(+), 31 deletions(-)\n>> create mode 100644 src/libcamera/shared_mem_object.cpp\n>>\n>> diff --git a/include/libcamera/internal/shared_mem_object.h b/include/libcamera/internal/shared_mem_object.h\n>> index bfb639ee..a4de6500 100644\n>> --- a/include/libcamera/internal/shared_mem_object.h\n>> +++ b/include/libcamera/internal/shared_mem_object.h\n>> @@ -7,11 +7,8 @@\n>> #pragma once\n>> \n>> #include \n>> -#include \n>> #include \n>> #include \n>> -#include \n>> -#include \n>> #include \n>> \n>> #include \n>> @@ -19,6 +16,59 @@\n>> \n>> namespace libcamera {\n>> \n>> +class SharedMem\n>> +{\n>> +public:\n>> +\tSharedMem()\n>> +\t\t: mem_(nullptr)\n>> +\t{\n>> +\t}\n>> +\n>> +\tSharedMem(const std::string &name, std::size_t size);\n>> +\n>> +\tSharedMem(SharedMem &&rhs)\n>> +\t{\n>> +\t\tthis->name_ = std::move(rhs.name_);\n>> +\t\tthis->fd_ = std::move(rhs.fd_);\n>> +\t\tthis->mem_ = rhs.mem_;\n>> +\t\trhs.mem_ = nullptr;\n>> +\t}\n>> +\n>> +\t~SharedMem()\n>> +\t{\n>> +\t\tif (mem_)\n>> +\t\t\tmunmap(mem_, size_);\n>> +\t}\n>> +\n>> +\t/* Make SharedMem non-copyable for now. */\n>> +\tLIBCAMERA_DISABLE_COPY(SharedMem)\n>> +\n>> +\tSharedMem &operator=(SharedMem &&rhs)\n>> +\t{\n>> +\t\tthis->name_ = std::move(rhs.name_);\n>> +\t\tthis->fd_ = std::move(rhs.fd_);\n>> +\t\tthis->mem_ = rhs.mem_;\n>> +\t\trhs.mem_ = nullptr;\n>> +\t\treturn *this;\n>> +\t}\n>> +\n>> +\tconst SharedFD &fd() const\n>> +\t{\n>> +\t\treturn fd_;\n>> +\t}\n>> +\n>> +\tvoid *mem() const\n>> +\t{\n>> +\t\treturn mem_;\n>> +\t}\n>> +\n>> +private:\n>> +\tstd::string name_;\n>> +\tSharedFD fd_;\n>> +\tsize_t size_;\n>> +\tvoid *mem_;\n>> +};\n>> +\n>> template\n>> class SharedMemObject\n>> {\n>> @@ -32,26 +82,11 @@ public:\n>> \n>> \ttemplate\n>> \tSharedMemObject(const std::string &name, Args &&...args)\n>> -\t\t: name_(name), obj_(nullptr)\n>> +\t\t: shMem_(name, SIZE), obj_(nullptr)\n>> \t{\n>> -\t\tvoid *mem;\n>> -\t\tint ret;\n>> +\t\tvoid *mem = shMem_.mem();\n>> \n>> -\t\tret = memfd_create(name_.c_str(), MFD_CLOEXEC);\n>> -\t\tif (ret < 0)\n>> -\t\t\treturn;\n>> -\n>> -\t\tfd_ = SharedFD(std::move(ret));\n>> -\t\tif (!fd_.isValid())\n>> -\t\t\treturn;\n>> -\n>> -\t\tret = ftruncate(fd_.get(), SIZE);\n>> -\t\tif (ret < 0)\n>> -\t\t\treturn;\n>> -\n>> -\t\tmem = mmap(nullptr, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,\n>> -\t\t\t fd_.get(), 0);\n>> -\t\tif (mem == MAP_FAILED)\n>> +\t\tif (mem == nullptr)\n>> \t\t\treturn;\n>> \n>> \t\tobj_ = new (mem) T(std::forward(args)...);\n>> @@ -59,18 +94,15 @@ public:\n>> \n>> \tSharedMemObject(SharedMemObject &&rhs)\n>> \t{\n>> -\t\tthis->name_ = std::move(rhs.name_);\n>> -\t\tthis->fd_ = std::move(rhs.fd_);\n>> +\t\tthis->shMem_ = std::move(rhs.shMem_);\n>> \t\tthis->obj_ = rhs.obj_;\n>> \t\trhs.obj_ = nullptr;\n>> \t}\n>> \n>> \t~SharedMemObject()\n>> \t{\n>> -\t\tif (obj_) {\n>> +\t\tif (obj_)\n>> \t\t\tobj_->~T();\n>> -\t\t\tmunmap(obj_, SIZE);\n>> -\t\t}\n>> \t}\n>> \n>> \t/* Make SharedMemObject non-copyable for now. */\n>> @@ -78,8 +110,7 @@ public:\n>> \n>> \tSharedMemObject &operator=(SharedMemObject &&rhs)\n>> \t{\n>> -\t\tthis->name_ = std::move(rhs.name_);\n>> -\t\tthis->fd_ = std::move(rhs.fd_);\n>> +\t\tthis->shMem_ = std::move(rhs.shMem_);\n>> \t\tthis->obj_ = rhs.obj_;\n>> \t\trhs.obj_ = nullptr;\n>> \t\treturn *this;\n>> @@ -107,7 +138,7 @@ public:\n>> \n>> \tconst SharedFD &fd() const\n>> \t{\n>> -\t\treturn fd_;\n>> +\t\treturn shMem_.fd();\n>> \t}\n>> \n>> \texplicit operator bool() const\n>> @@ -116,8 +147,7 @@ public:\n>> \t}\n>> \n>> private:\n>> -\tstd::string name_;\n>> -\tSharedFD fd_;\n>> +\tSharedMem shMem_;\n>> \tT *obj_;\n>> };\n>> \n>> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build\n>> index 3c5e43df..94a95ae3 100644\n>> --- a/src/libcamera/meson.build\n>> +++ b/src/libcamera/meson.build\n>> @@ -41,6 +41,7 @@ libcamera_sources = files([\n>> 'process.cpp',\n>> 'pub_key.cpp',\n>> 'request.cpp',\n>> + 'shared_mem_object.cpp',\n>> 'source_paths.cpp',\n>> 'stream.cpp',\n>> 'sysfs.cpp',\n>> diff --git a/src/libcamera/shared_mem_object.cpp b/src/libcamera/shared_mem_object.cpp\n>> new file mode 100644\n>> index 00000000..06bbee38\n>> --- /dev/null\n>> +++ b/src/libcamera/shared_mem_object.cpp\n>> @@ -0,0 +1,191 @@\n>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */\n>> +/*\n>> + * Copyright (C) 2023, Raspberry Pi Ltd\n>> + *\n>> + * shared_mem_object.cpp - Helper class for shared memory allocations\n>> + */\n>> +\n>> +#include \"libcamera/internal/shared_mem_object.h\"\n>> +\n>> +#include \n>> +#include \n>> +\n>> +/**\n>> + * \\file shared_mem_object.cpp\n>> + * \\brief Helper class for shared memory allocations\n>> + */\n>> +\n>> +namespace libcamera {\n>> +\n>> +/**\n>> + * \\class SharedMem\n>> + * \\brief Helper class for allocating shared memory\n>> + *\n>> + * Memory is allocated and exposed as a SharedFD for use across IPC boundaries.\n>> + *\n>> + * SharedMem allocates the shared memory of the given size and maps it.\n>> + * To check that the shared memory was allocated and mapped successfully, one\n>> + * needs to verify that the pointer to the shared memory returned by SharedMem::mem()\n>> + * is not nullptr.\n>> + *\n>> + * To access the shared memory from another process the SharedFD should be passed\n>> + * to that process, and then the shared memory should be mapped into that process\n>> + * address space by calling mmap().\n>> + *\n>> + * A single memfd is created for every SharedMem. If there is a need to allocate\n>> + * a large number of objects in shared memory, these objects should be grouped\n>> + * together and use the shared memory allocated by a single SharedMem object if\n>> + * possible. This will help to minimize the number of created memfd's.\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMem::SharedMem(const std::string &name, std::size_t size)\n>> + * \\brief Contstructor for the SharedMem\n>> + * \\param[in] name Name of the SharedMem\n>> + * \\param[in] size Size of the shared memory to allocate and map\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMem::SharedMem(SharedMem &&rhs)\n>> + * \\brief Move constructor for SharedMem\n>> + * \\param[in] rhs The object to move\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMem::~SharedMem()\n>> + * \\brief SharedMem destructor\n>> + *\n>> + * Unmaps the allocated shared memory. Decrements the shared memory descriptor use\n>> + * count.\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMem &SharedMem::operator=(SharedMem &&rhs)\n>> + * \\brief Move constructor for SharedMem\n>> + * \\param[in] rhs The object to move\n>> + */\n>> +\n>> +/**\n>> + * \\fn const SharedFD &SharedMem::fd() const\n>> + * \\brief Gets the file descriptor for the underlaying shared memory\n>> + * \\return The file descriptor\n>> + */\n>> +\n>> +/**\n>> + * \\fn void *SharedMem::mem() const\n>> + * \\brief Gets the pointer to the underlaying shared memory\n>> + * \\return The pointer to the shared memory\n>> + */\n>> +\n>> +SharedMem::SharedMem(const std::string &name, std::size_t size)\n>> +\t: name_(name), size_(size), mem_(nullptr)\n>> +{\n>> +\tint fd = memfd_create(name_.c_str(), MFD_CLOEXEC);\n>> +\tif (fd < 0)\n>> +\t\treturn;\n>> +\n>> +\tfd_ = SharedFD(std::move(fd));\n>> +\tif (!fd_.isValid())\n>> +\t\treturn;\n>> +\n>> +\tif (ftruncate(fd_.get(), size_) < 0)\n>> +\t\treturn;\n>> +\n>> +\tmem_ = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED,\n>> +\t\t fd_.get(), 0);\n>> +\tif (mem_ == MAP_FAILED)\n>> +\t\tmem_ = nullptr;\n>> +}\n>> +\n>> +/**\n>> + * \\class SharedMemObject\n>> + * \\brief Helper class for allocating objects in shared memory\n>> + *\n>> + * Memory is allocated and exposed as a SharedFD for use across IPC boundaries.\n>> + *\n>> + * Given the type of the object to be created in shared memory and the arguments\n>> + * to pass to this object's constructor, SharedMemObject allocates the shared memory\n>> + * of the size of the object and constructs the object in this memory. To check that\n>> + * the SharedMemObject was created successfully, one needs to verify that the\n>> + * underlying SharedFD (the reference to it is returned by SharedMemObject::fd() member\n>> + * function) is valid. The object created in the shared memory can be accessed using\n>> + * the SharedMemObject::operator*() indirection operator. Its members can be accessed\n>> + * with the SharedMemObject::operator->() member of pointer operator.\n> \n> But it can still happen that SharedMemObject::fd() is all right but the object\n> returned from the operators is nullptr, right?\n\nRight (if the memory is allocated and truncated OK, but mmap fails).\n\n> It would be good to clarify this and refer to the bool operator here.\n\nI will.\nI'll also modify the SoftwareIsp constructor to use 'if (!sharedParams_)' instead of\n'if (!sharedParams_.fd().isValid())'.\n\n>> + *\n>> + * To access the object from another process the SharedFD should be passed to that\n>> + * process, and the shared memory should be mapped by calling mmap().\n>> + *\n>> + * A single memfd is created for every SharedMemObject. If there is a need to allocate\n>> + * a large number of objects in shared memory, these objects should be grouped into a\n>> + * single large object to keep the number of created memfd's reasonably small.\n>> + */\n>> +\n>> +/**\n>> + * \\var SharedMemObject::SIZE\n>> + * \\brief The size of the object that is going to be stored here\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMemObject< T >::SharedMemObject(const std::string &name, Args &&...args)\n>> + * \\brief Contstructor for the SharedMemObject\n> ^^^^^^^^^^^^\n> \n> Constructor\n\nOK, I'll fix these misprints (they are two).\n\nThanks,\nAndrei\n\n>> + * \\param[in] name Name of the SharedMemObject\n>> + * \\param[in] args Args to pass to the constructor of the object in shared memory\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMemObject::SharedMemObject(SharedMemObject &&rhs)\n>> + * \\brief Move constructor for SharedMemObject\n>> + * \\param[in] rhs The object to move\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMemObject::~SharedMemObject()\n>> + * \\brief SharedMemObject destructor\n>> + *\n>> + * Destroys the object created in the shared memory and then unmaps the shared memory.\n>> + * Decrements the shared memory descriptor use count.\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMemObject::operator=(SharedMemObject &&rhs)\n>> + * \\brief Operator= for SharedMemObject\n>> + * \\param[in] rhs The SharedMemObject object to take the data from\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMemObject::operator->()\n>> + * \\brief Operator-> for SharedMemObject\n>> + * \\return The pointer to the object\n>> + */\n>> +\n>> +/**\n>> + * \\fn const T *SharedMemObject::operator->() const\n>> + * \\brief Operator-> for SharedMemObject\n>> + * \\return The pointer to the const object\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMemObject::operator*()\n>> + * \\brief Operator* for SharedMemObject\n>> + * \\return The reference to the object\n>> + */\n>> +\n>> +/**\n>> + * \\fn const T &SharedMemObject::operator*() const\n>> + * \\brief Operator* for SharedMemObject\n>> + * \\return Const reference to the object\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMemObject::fd()\n>> + * \\brief Gets the file descriptor for the underlaying storage file\n>> + * \\return The shared memory file descriptor (as SharedFD)\n>> + */\n>> +\n>> +/**\n>> + * \\fn SharedMemObject::operator bool()\n>> + * \\brief Operator bool() for SharedMemObject\n>> + * \\return True if the object was created OK in the shared memory, false otherwise\n>> + */\n>> +\n>> +} // namespace libcamera\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 E8179C3257\n\tfor ;\n\tSun, 18 Feb 2024 19:22:58 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby 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id\n\to11-20020ac24e8b000000b00512b0692ddemr975901lfr.10.1708284176108; \n\tSun, 18 Feb 2024 11:22:56 -0800 (PST)","Message-ID":"","Date":"Sun, 18 Feb 2024 22:22:54 +0300","MIME-Version":"1.0","User-Agent":"Mozilla Thunderbird","Subject":"Re: [PATCH v3 05/16] libcamera: shared_mem_object: reorganize the\n\tcode and document the SharedMemObject class","To":"Milan Zamazal , Hans de Goede ","References":"<20240214170122.60754-1-hdegoede@redhat.com>\n\t<20240214170122.60754-6-hdegoede@redhat.com>\n\t<87plwxdfcu.fsf@redhat.com>","Content-Language":"en-US","From":"Andrei Konovalov ","In-Reply-To":"<87plwxdfcu.fsf@redhat.com>","Content-Type":"text/plain; charset=UTF-8; format=flowed","Content-Transfer-Encoding":"7bit","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":"Bryan O'Donoghue ,\n\tlibcamera-devel@lists.libcamera.org, Maxime Ripard , \n\tPavel Machek , Dennis Bonke ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":28693,"web_url":"https://patchwork.libcamera.org/comment/28693/","msgid":"<8fcf18ff-e855-4763-979d-eb40f2df350f@gmail.com>","date":"2024-02-19T12:18:57","subject":"Re: [PATCH v3 05/16] libcamera: shared_mem_object: reorganize the\n\tcode and document the SharedMemObject class","submitter":{"id":179,"url":"https://patchwork.libcamera.org/api/people/179/","name":"Andrei Konovalov","email":"andrey.konovalov.ynk@gmail.com"},"content":"Hi Naushir,\n\nOn 15.02.2024 16:39, Naushir Patuck wrote:\n> Hi Hans,\n> \n> On Wed, 14 Feb 2024 at 17:01, Hans de Goede wrote:\n>>\n>> From: Andrei Konovalov \n>>\n>> Split the parts which doesn't otherwise depend on the type T or\n>> arguments Args out of the SharedMemObject class into a new\n>> SharedMem class.\n>>\n>> Doxygen documentation by Dennis Bonke and Andrei Konovalov.\n>>\n>> Reviewed-by: Pavel Machek \n>> Co-developed-by: Dennis Bonke \n>> Signed-off-by: Dennis Bonke \n>> Signed-off-by: Andrei Konovalov \n>> ---\n>> .../libcamera/internal/shared_mem_object.h | 92 ++++++---\n>> src/libcamera/meson.build | 1 +\n>> src/libcamera/shared_mem_object.cpp | 191 ++++++++++++++++++\n>> 3 files changed, 253 insertions(+), 31 deletions(-)\n>> create mode 100644 src/libcamera/shared_mem_object.cpp\n>>\n>> diff --git a/include/libcamera/internal/shared_mem_object.h b/include/libcamera/internal/shared_mem_object.h\n>> index bfb639ee..a4de6500 100644\n>> --- a/include/libcamera/internal/shared_mem_object.h\n>> +++ b/include/libcamera/internal/shared_mem_object.h\n>> @@ -7,11 +7,8 @@\n>> #pragma once\n>>\n>> #include \n>> -#include \n>> #include \n>> #include \n>> -#include \n>> -#include \n>> #include \n>>\n>> #include \n>> @@ -19,6 +16,59 @@\n>>\n>> namespace libcamera {\n>>\n>> +class SharedMem\n>> +{\n>> +public:\n>> + SharedMem()\n>> + : mem_(nullptr)\n>> + {\n>> + }\n>> +\n>> + SharedMem(const std::string &name, std::size_t size);\n>> +\n>> + SharedMem(SharedMem &&rhs)\n>> + {\n>> + this->name_ = std::move(rhs.name_);\n>> + this->fd_ = std::move(rhs.fd_);\n>> + this->mem_ = rhs.mem_;\n>> + rhs.mem_ = nullptr;\n>> + }\n>> +\n>> + ~SharedMem()\n>> + {\n>> + if (mem_)\n>> + munmap(mem_, size_);\n>> + }\n>> +\n>> + /* Make SharedMem non-copyable for now. */\n>> + LIBCAMERA_DISABLE_COPY(SharedMem)\n>> +\n>> + SharedMem &operator=(SharedMem &&rhs)\n>> + {\n>> + this->name_ = std::move(rhs.name_);\n>> + this->fd_ = std::move(rhs.fd_);\n>> + this->mem_ = rhs.mem_;\n>> + rhs.mem_ = nullptr;\n>> + return *this;\n>> + }\n>> +\n>> + const SharedFD &fd() const\n>> + {\n>> + return fd_;\n>> + }\n>> +\n>> + void *mem() const\n>> + {\n>> + return mem_;\n>> + }\n>> +\n>> +private:\n>> + std::string name_;\n>> + SharedFD fd_;\n>> + size_t size_;\n>> + void *mem_;\n>> +};\n>> +\n>> template\n>> class SharedMemObject\n> \n> Would it make sense to have SharedMemObject derived from SharedMem?\n> Then you would only need a constructor and destructor implemented for\n> SharedMemObject, and all other accessors can be through the base\n> class... i think?\n\nDoes this updated patch (attached) looks OK for you?\n\nThanks,\nAndrei","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 8AB3CBF415\n\tfor ;\n\tMon, 19 Feb 2024 12:19:02 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id C95EE62807;\n\tMon, 19 Feb 2024 13:19:01 +0100 (CET)","from mail-ej1-x631.google.com (mail-ej1-x631.google.com\n\t[IPv6:2a00:1450:4864:20::631])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id B1DED61C9E\n\tfor ;\n\tMon, 19 Feb 2024 13:18:59 +0100 (CET)","by mail-ej1-x631.google.com 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2002:a17:906:7150:b0:a3e:75b2:4ffa with SMTP id\n\tz16-20020a170906715000b00a3e75b24ffamr3180943ejj.13.1708345138909; \n\tMon, 19 Feb 2024 04:18:58 -0800 (PST)","Content-Type":"multipart/mixed;\n\tboundary=\"------------xnQyVrm2naB2eeXo4OKj1AAG\"","Message-ID":"<8fcf18ff-e855-4763-979d-eb40f2df350f@gmail.com>","Date":"Mon, 19 Feb 2024 15:18:57 +0300","MIME-Version":"1.0","User-Agent":"Mozilla Thunderbird","Subject":"Re: [PATCH v3 05/16] libcamera: shared_mem_object: reorganize the\n\tcode and document the SharedMemObject class","Content-Language":"en-US","To":"Naushir Patuck ","References":"<20240214170122.60754-1-hdegoede@redhat.com>\n\t<20240214170122.60754-6-hdegoede@redhat.com>\n\t","From":"Andrei Konovalov ","In-Reply-To":"","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":"Maxime Ripard , libcamera-devel@lists.libcamera.org, \n\tPavel Machek ,\n\tBryan O'Donoghue , \n\tDennis Bonke ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":28694,"web_url":"https://patchwork.libcamera.org/comment/28694/","msgid":"","date":"2024-02-19T12:25:42","subject":"Re: [PATCH v3 05/16] libcamera: shared_mem_object: reorganize the\n\tcode and document the SharedMemObject class","submitter":{"id":179,"url":"https://patchwork.libcamera.org/api/people/179/","name":"Andrei Konovalov","email":"andrey.konovalov.ynk@gmail.com"},"content":"On 19.02.2024 15:18, Andrei Konovalov wrote:\n> Hi Naushir,\n> \n> On 15.02.2024 16:39, Naushir Patuck wrote:\n>> Hi Hans,\n>>\n>> On Wed, 14 Feb 2024 at 17:01, Hans de Goede wrote:\n>>>\n>>> From: Andrei Konovalov \n>>>\n>>> Split the parts which doesn't otherwise depend on the type T or\n>>> arguments Args out of the SharedMemObject class into a new\n>>> SharedMem class.\n>>>\n>>> Doxygen documentation by Dennis Bonke and Andrei Konovalov.\n>>>\n>>> Reviewed-by: Pavel Machek \n>>> Co-developed-by: Dennis Bonke \n>>> Signed-off-by: Dennis Bonke \n>>> Signed-off-by: Andrei Konovalov \n>>> ---\n>>>   .../libcamera/internal/shared_mem_object.h    |  92 ++++++---\n>>>   src/libcamera/meson.build                     |   1 +\n>>>   src/libcamera/shared_mem_object.cpp           | 191 ++++++++++++++++++\n>>>   3 files changed, 253 insertions(+), 31 deletions(-)\n>>>   create mode 100644 src/libcamera/shared_mem_object.cpp\n>>>\n>>> diff --git a/include/libcamera/internal/shared_mem_object.h b/include/libcamera/internal/shared_mem_object.h\n\n>> Would it make sense to have SharedMemObject derived from SharedMem?\n>> Then you would only need a constructor and destructor implemented for\n>> SharedMemObject, and all other accessors can be through the base\n>> class... i think?\n> \n> Does this updated patch (attached) looks OK for you?\n\nOops.. The attachment wasn't inlined. Resending the patch in an easier to comment on\nform.\n\nThanks,\nAndrei\n\n\nFrom: Andrei Konovalov \nDate: Wed, 31 Jan 2024 02:17:34 +0300\nSubject: [PATCH 05/16] libcamera: shared_mem_object: reorganize the code and\n document the SharedMemObject class\n\nSplit the parts which doesn't otherwise depend on the type T or\narguments Args out of the SharedMemObject class into a new\nSharedMem class.\n\nDoxygen documentation by Dennis Bonke and Andrei Konovalov.\n\nReviewed-by: Pavel Machek \nCo-developed-by: Dennis Bonke \nSigned-off-by: Dennis Bonke \nSigned-off-by: Andrei Konovalov \n---\n .../libcamera/internal/shared_mem_object.h | 101 ++++++----\n src/libcamera/meson.build | 1 +\n src/libcamera/shared_mem_object.cpp | 189 ++++++++++++++++++\n 3 files changed, 252 insertions(+), 39 deletions(-)\n create mode 100644 src/libcamera/shared_mem_object.cpp\n\ndiff --git a/include/libcamera/internal/shared_mem_object.h b/include/libcamera/internal/shared_mem_object.h\nindex bfb639ee..bb9cddcd 100644\n--- a/include/libcamera/internal/shared_mem_object.h\n+++ b/include/libcamera/internal/shared_mem_object.h\n@@ -7,11 +7,8 @@\n #pragma once\n\n #include \n-#include \n #include \n #include \n-#include \n-#include \n #include \n\n #include \n@@ -19,58 +16,92 @@\n\n namespace libcamera {\n\n+class SharedMem\n+{\n+public:\n+\tSharedMem()\n+\t\t: mem_(nullptr)\n+\t{\n+\t}\n+\n+\tSharedMem(const std::string &name, std::size_t size);\n+\n+\tSharedMem(SharedMem &&rhs)\n+\t{\n+\t\tthis->name_ = std::move(rhs.name_);\n+\t\tthis->fd_ = std::move(rhs.fd_);\n+\t\tthis->mem_ = rhs.mem_;\n+\t\trhs.mem_ = nullptr;\n+\t}\n+\n+\tvirtual ~SharedMem()\n+\t{\n+\t\tif (mem_)\n+\t\t\tmunmap(mem_, size_);\n+\t}\n+\n+\t/* Make SharedMem non-copyable for now. */\n+\tLIBCAMERA_DISABLE_COPY(SharedMem)\n+\n+\tSharedMem &operator=(SharedMem &&rhs)\n+\t{\n+\t\tthis->name_ = std::move(rhs.name_);\n+\t\tthis->fd_ = std::move(rhs.fd_);\n+\t\tthis->mem_ = rhs.mem_;\n+\t\trhs.mem_ = nullptr;\n+\t\treturn *this;\n+\t}\n+\n+\tconst SharedFD &fd() const\n+\t{\n+\t\treturn fd_;\n+\t}\n+\n+\tvoid *mem() const\n+\t{\n+\t\treturn mem_;\n+\t}\n+\n+private:\n+\tstd::string name_;\n+\tSharedFD fd_;\n+\tsize_t size_;\n+protected:\n+\tvoid *mem_;\n+};\n+\n template\n-class SharedMemObject\n+class SharedMemObject : public SharedMem\n {\n public:\n \tstatic constexpr std::size_t SIZE = sizeof(T);\n\n \tSharedMemObject()\n-\t\t: obj_(nullptr)\n+\t\t: SharedMem(), obj_(nullptr)\n \t{\n \t}\n\n \ttemplate\n \tSharedMemObject(const std::string &name, Args &&...args)\n-\t\t: name_(name), obj_(nullptr)\n+\t\t: SharedMem(name, SIZE), obj_(nullptr)\n \t{\n-\t\tvoid *mem;\n-\t\tint ret;\n-\n-\t\tret = memfd_create(name_.c_str(), MFD_CLOEXEC);\n-\t\tif (ret < 0)\n-\t\t\treturn;\n-\n-\t\tfd_ = SharedFD(std::move(ret));\n-\t\tif (!fd_.isValid())\n-\t\t\treturn;\n-\n-\t\tret = ftruncate(fd_.get(), SIZE);\n-\t\tif (ret < 0)\n+\t\tif (mem_ == nullptr)\n \t\t\treturn;\n\n-\t\tmem = mmap(nullptr, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,\n-\t\t\t fd_.get(), 0);\n-\t\tif (mem == MAP_FAILED)\n-\t\t\treturn;\n-\n-\t\tobj_ = new (mem) T(std::forward(args)...);\n+\t\tobj_ = new (mem_) T(std::forward(args)...);\n \t}\n\n \tSharedMemObject(SharedMemObject &&rhs)\n+\t\t: SharedMem(std::move(rhs))\n \t{\n-\t\tthis->name_ = std::move(rhs.name_);\n-\t\tthis->fd_ = std::move(rhs.fd_);\n \t\tthis->obj_ = rhs.obj_;\n \t\trhs.obj_ = nullptr;\n \t}\n\n \t~SharedMemObject()\n \t{\n-\t\tif (obj_) {\n+\t\tif (obj_)\n \t\t\tobj_->~T();\n-\t\t\tmunmap(obj_, SIZE);\n-\t\t}\n \t}\n\n \t/* Make SharedMemObject non-copyable for now. */\n@@ -78,8 +109,7 @@ public:\n\n \tSharedMemObject &operator=(SharedMemObject &&rhs)\n \t{\n-\t\tthis->name_ = std::move(rhs.name_);\n-\t\tthis->fd_ = std::move(rhs.fd_);\n+\t\tSharedMem::operator=(std::move(rhs));\n \t\tthis->obj_ = rhs.obj_;\n \t\trhs.obj_ = nullptr;\n \t\treturn *this;\n@@ -105,19 +135,12 @@ public:\n \t\treturn *obj_;\n \t}\n\n-\tconst SharedFD &fd() const\n-\t{\n-\t\treturn fd_;\n-\t}\n-\n \texplicit operator bool() const\n \t{\n \t\treturn !!obj_;\n \t}\n\n private:\n-\tstd::string name_;\n-\tSharedFD fd_;\n \tT *obj_;\n };\n\ndiff --git a/src/libcamera/meson.build b/src/libcamera/meson.build\nindex 3c5e43df..94a95ae3 100644\n--- a/src/libcamera/meson.build\n+++ b/src/libcamera/meson.build\n@@ -41,6 +41,7 @@ libcamera_sources = files([\n 'process.cpp',\n 'pub_key.cpp',\n 'request.cpp',\n+ 'shared_mem_object.cpp',\n 'source_paths.cpp',\n 'stream.cpp',\n 'sysfs.cpp',\ndiff --git a/src/libcamera/shared_mem_object.cpp b/src/libcamera/shared_mem_object.cpp\nnew file mode 100644\nindex 00000000..dbaa7351\n--- /dev/null\n+++ b/src/libcamera/shared_mem_object.cpp\n@@ -0,0 +1,189 @@\n+/* SPDX-License-Identifier: LGPL-2.1-or-later */\n+/*\n+ * Copyright (C) 2023, Raspberry Pi Ltd\n+ *\n+ * shared_mem_object.cpp - Helper class for shared memory allocations\n+ */\n+\n+#include \"libcamera/internal/shared_mem_object.h\"\n+\n+#include \n+#include \n+\n+/**\n+ * \\file shared_mem_object.cpp\n+ * \\brief Helper class for shared memory allocations\n+ */\n+\n+namespace libcamera {\n+\n+/**\n+ * \\class SharedMem\n+ * \\brief Helper class for allocating shared memory\n+ *\n+ * Memory is allocated and exposed as a SharedFD for use across IPC boundaries.\n+ *\n+ * SharedMem allocates the shared memory of the given size and maps it.\n+ * To ensure that the shared memory was allocated and mapped successfully, one\n+ * needs to verify that the overloaded bool() operator returns true.\n+ *\n+ * To access the shared memory from another process the SharedFD should be passed\n+ * to that process, and then the shared memory should be mapped into that process\n+ * address space by calling mmap().\n+ *\n+ * A single memfd is created for every SharedMem. If there is a need to allocate\n+ * a large number of objects in shared memory, these objects should be grouped\n+ * together and use the shared memory allocated by a single SharedMem object if\n+ * possible. This will help to minimize the number of created memfd's.\n+ */\n+\n+/**\n+ * \\fn SharedMem::SharedMem(const std::string &name, std::size_t size)\n+ * \\brief Constructor for the SharedMem\n+ * \\param[in] name Name of the SharedMem\n+ * \\param[in] size Size of the shared memory to allocate and map\n+ */\n+\n+/**\n+ * \\fn SharedMem::SharedMem(SharedMem &&rhs)\n+ * \\brief Move constructor for SharedMem\n+ * \\param[in] rhs The object to move\n+ */\n+\n+/**\n+ * \\fn SharedMem::~SharedMem()\n+ * \\brief SharedMem destructor\n+ *\n+ * Unmaps the allocated shared memory. Decrements the shared memory descriptor use\n+ * count.\n+ */\n+\n+/**\n+ * \\fn SharedMem &SharedMem::operator=(SharedMem &&rhs)\n+ * \\brief Move constructor for SharedMem\n+ * \\param[in] rhs The object to move\n+ */\n+\n+/**\n+ * \\fn const SharedFD &SharedMem::fd() const\n+ * \\brief Gets the file descriptor for the underlying shared memory\n+ * \\return The file descriptor\n+ */\n+\n+/**\n+ * \\fn void *SharedMem::mem() const\n+ * \\brief Gets the pointer to the underlying shared memory\n+ * \\return The pointer to the shared memory\n+ */\n+\n+SharedMem::SharedMem(const std::string &name, std::size_t size)\n+\t: name_(name), size_(size), mem_(nullptr)\n+{\n+\tint fd = memfd_create(name_.c_str(), MFD_CLOEXEC);\n+\tif (fd < 0)\n+\t\treturn;\n+\n+\tfd_ = SharedFD(std::move(fd));\n+\tif (!fd_.isValid())\n+\t\treturn;\n+\n+\tif (ftruncate(fd_.get(), size_) < 0)\n+\t\treturn;\n+\n+\tmem_ = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED,\n+\t\t fd_.get(), 0);\n+\tif (mem_ == MAP_FAILED)\n+\t\tmem_ = nullptr;\n+}\n+\n+/**\n+ * \\var SharedMem::mem_\n+ * \\brief Pointer to the shared memory allocated\n+ */\n+\n+/**\n+ * \\class SharedMemObject\n+ * \\brief Helper class for allocating objects in shared memory\n+ *\n+ * Memory is allocated and exposed as a SharedFD for use across IPC boundaries.\n+ *\n+ * Given the type of the object to be created in shared memory and the arguments\n+ * to pass to this object's constructor, SharedMemObject allocates the shared memory\n+ * of the size of the object and constructs the object in this memory. To check that\n+ * the SharedMemObject was created successfully, one needs to verify that the\n+ * underlying SharedFD (the reference to it is returned by SharedMemObject::fd() member\n+ * function) is valid. The object created in the shared memory can be accessed using\n+ * the SharedMemObject::operator*() indirection operator. Its members can be accessed\n+ * with the SharedMemObject::operator->() member of pointer operator.\n+ *\n+ * To access the object from another process the SharedFD should be passed to that\n+ * process, and the shared memory should be mapped by calling mmap().\n+ *\n+ * A single memfd is created for every SharedMemObject. If there is a need to allocate\n+ * a large number of objects in shared memory, these objects should be grouped into a\n+ * single large object to keep the number of created memfd's reasonably small.\n+ */\n+\n+/**\n+ * \\var SharedMemObject::SIZE\n+ * \\brief The size of the object that is going to be stored here\n+ */\n+\n+/**\n+ * \\fn SharedMemObject< T >::SharedMemObject(const std::string &name, Args &&...args)\n+ * \\brief Constructor for the SharedMemObject\n+ * \\param[in] name Name of the SharedMemObject\n+ * \\param[in] args Args to pass to the constructor of the object in shared memory\n+ */\n+\n+/**\n+ * \\fn SharedMemObject::SharedMemObject(SharedMemObject &&rhs)\n+ * \\brief Move constructor for SharedMemObject\n+ * \\param[in] rhs The object to move\n+ */\n+\n+/**\n+ * \\fn SharedMemObject::~SharedMemObject()\n+ * \\brief SharedMemObject destructor\n+ *\n+ * Destroys the object created in the shared memory and then unmaps the shared memory.\n+ * Decrements the shared memory descriptor use count.\n+ */\n+\n+/**\n+ * \\fn SharedMemObject::operator=(SharedMemObject &&rhs)\n+ * \\brief Operator= for SharedMemObject\n+ * \\param[in] rhs The SharedMemObject object to take the data from\n+ */\n+\n+/**\n+ * \\fn SharedMemObject::operator->()\n+ * \\brief Operator-> for SharedMemObject\n+ * \\return The pointer to the object\n+ */\n+\n+/**\n+ * \\fn const T *SharedMemObject::operator->() const\n+ * \\brief Operator-> for SharedMemObject\n+ * \\return The pointer to the const object\n+ */\n+\n+/**\n+ * \\fn SharedMemObject::operator*()\n+ * \\brief Operator* for SharedMemObject\n+ * \\return The reference to the object\n+ */\n+\n+/**\n+ * \\fn const T &SharedMemObject::operator*() const\n+ * \\brief Operator* for SharedMemObject\n+ * \\return Const reference to the object\n+ */\n+\n+/**\n+ * \\fn SharedMemObject::operator bool()\n+ * \\brief Operator bool() for SharedMemObject\n+ * \\return True if the object was created OK in the shared memory, false otherwise\n+ */\n+\n+} // namespace libcamera","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 D4FABC3257\n\tfor ;\n\tMon, 19 Feb 2024 12:25:46 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 0AEAD62807;\n\tMon, 19 Feb 2024 13:25:46 +0100 (CET)","from mail-ed1-x534.google.com (mail-ed1-x534.google.com\n\t[IPv6:2a00:1450:4864:20::534])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 65BA761C9E\n\tfor ;\n\tMon, 19 Feb 2024 13:25:44 +0100 (CET)","by mail-ed1-x534.google.com with SMTP id\n\t4fb4d7f45d1cf-55a179f5fa1so5741239a12.0\n\tfor ;\n\tMon, 19 Feb 2024 04:25:44 -0800 (PST)","from [192.168.118.26] ([87.116.165.182])\n\tby smtp.gmail.com with ESMTPSA id\n\tef3-20020a05640228c300b005640022af58sm2649420edb.83.2024.02.19.04.25.42\n\t(version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128);\n\tMon, 19 Feb 2024 04:25:43 -0800 (PST)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n\tunprotected) header.d=gmail.com header.i=@gmail.com\n\theader.b=\"Sd52rpiT\"; 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\n\tMon, 19 Feb 2024 04:25:43 -0800 (PST)","Message-ID":"","Date":"Mon, 19 Feb 2024 15:25:42 +0300","MIME-Version":"1.0","User-Agent":"Mozilla Thunderbird","Subject":"Re: [PATCH v3 05/16] libcamera: shared_mem_object: reorganize the\n\tcode and document the SharedMemObject class","Content-Language":"en-US","From":"Andrei Konovalov ","To":"Naushir Patuck ","References":"<20240214170122.60754-1-hdegoede@redhat.com>\n\t<20240214170122.60754-6-hdegoede@redhat.com>\n\t\n\t<8fcf18ff-e855-4763-979d-eb40f2df350f@gmail.com>","In-Reply-To":"<8fcf18ff-e855-4763-979d-eb40f2df350f@gmail.com>","Content-Type":"text/plain; charset=UTF-8; format=flowed","Content-Transfer-Encoding":"8bit","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":"Maxime Ripard , libcamera-devel@lists.libcamera.org, \n\tPavel Machek ,\n\tBryan O'Donoghue , \n\tDennis Bonke ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]