libcamera: Switch to FrameBuffer interface

Switch to the FrameBuffer interface where all buffers are treated as
external buffers and are allocated outside the camera. Applications
allocating buffers using libcamera are switched to use the
FrameBufferAllocator helper.

Follow-up changes to this one will finalize the transition to the new
FrameBuffer interface by removing code that is left unused after this
change.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

8 files changed, 85 insertions, 209 deletions

diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index 20340167..3fe40feb 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -695,12 +695,6 @@ int Camera::configure(CameraConfiguration *config)
 
 		stream->configuration_ = cfg;
 		activeStreams_.insert(stream);
-
-		/*
-		 * Allocate buffer objects in the pool.
-		 * Memory will be allocated and assigned later.
-		 */
-		stream->createBuffers(cfg.memoryType, cfg.bufferCount);
 	}
 
 	state_ = CameraConfigured;
@@ -756,14 +750,6 @@ int Camera::freeBuffers()
 	if (!stateIs(CameraPrepared))
 		return -EACCES;
 
-	for (Stream *stream : activeStreams_) {
-		/*
-		 * All mappings must be destroyed before buffers can be freed
-		 * by the V4L2 device that has allocated them.
-		 */
-		stream->destroyBuffers();
-	}
-
 	state_ = CameraConfigured;
 
 	return pipe_->freeBuffers(this, activeStreams_);
@@ -834,24 +820,11 @@ int Camera::queueRequest(Request *request)
 
 	for (auto const &it : request->buffers()) {
 		Stream *stream = it.first;
-		Buffer *buffer = it.second;
 
 		if (activeStreams_.find(stream) == activeStreams_.end()) {
 			LOG(Camera, Error) << "Invalid request";
 			return -EINVAL;
 		}
-
-		if (stream->memoryType() == ExternalMemory) {
-			int index = stream->mapBuffer(buffer);
-			if (index < 0) {
-				LOG(Camera, Error) << "No buffer memory available";
-				return -ENOMEM;
-			}
-
-			buffer->index_ = index;
-		}
-
-		buffer->mem_ = &stream->buffers()[buffer->index_];
 	}
 
 	return pipe_->queueRequest(this, request);
@@ -880,6 +853,13 @@ int Camera::start()
 
 	LOG(Camera, Debug) << "Starting capture";
 
+	for (Stream *stream : activeStreams_) {
+		if (allocator_ && !allocator_->buffers(stream).empty())
+			continue;
+
+		pipe_->importFrameBuffers(this, stream);
+	}
+
 	int ret = pipe_->start(this);
 	if (ret)
 		return ret;
@@ -915,6 +895,13 @@ int Camera::stop()
 
 	pipe_->stop(this);
 
+	for (Stream *stream : activeStreams_) {
+		if (allocator_ && !allocator_->buffers(stream).empty())
+			continue;
+
+		pipe_->freeFrameBuffers(this, stream);
+	}
+
 	return 0;
 }
 
@@ -928,13 +915,6 @@ int Camera::stop()
  */
 void Camera::requestComplete(Request *request)
 {
-	for (auto it : request->buffers()) {
-		Stream *stream = it.first;
-		Buffer *buffer = it.second;
-		if (stream->memoryType() == ExternalMemory)
-			stream->unmapBuffer(buffer);
-	}
-
 	requestCompleted.emit(request);
 	delete request;
 }
diff --git a/src/libcamera/include/pipeline_handler.h b/src/libcamera/include/pipeline_handler.h
index 560be3ba..27f3852c 100644
--- a/src/libcamera/include/pipeline_handler.h
+++ b/src/libcamera/include/pipeline_handler.h
@@ -21,12 +21,12 @@
 
 namespace libcamera {
 
-class Buffer;
 class Camera;
 class CameraConfiguration;
 class CameraManager;
 class DeviceEnumerator;
 class DeviceMatch;
+class FrameBuffer;
 class MediaDevice;
 class PipelineHandler;
 class Request;
@@ -85,7 +85,8 @@ public:
 
 	int queueRequest(Camera *camera, Request *request);
 
-	bool completeBuffer(Camera *camera, Request *request, Buffer *buffer);
+	bool completeBuffer(Camera *camera, Request *request,
+			    FrameBuffer *buffer);
 	void completeRequest(Camera *camera, Request *request);
 
 	const char *name() const { return name_; }
diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index b73f0f07..065f5d98 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -31,6 +31,8 @@ namespace libcamera {
 
 LOG_DEFINE_CATEGORY(IPU3)
 
+class IPU3CameraData;
+
 class ImgUDevice
 {
 public:
@@ -44,7 +46,6 @@ public:
 		V4L2VideoDevice *dev;
 		unsigned int pad;
 		std::string name;
-		BufferPool *pool;
 		std::vector<std::unique_ptr<FrameBuffer>> buffers;
 	};
 
@@ -71,9 +72,7 @@ public:
 	int configureOutput(ImgUOutput *output,
 			    const StreamConfiguration &cfg);
 
-	int importOutputBuffers(ImgUOutput *output, BufferPool *pool);
-	int exportOutputBuffers(ImgUOutput *output, BufferPool *pool);
-	void freeBuffers();
+	void freeBuffers(IPU3CameraData *data);
 
 	int start();
 	int stop();
@@ -93,9 +92,6 @@ public:
 	ImgUOutput viewfinder_;
 	ImgUOutput stat_;
 	/* \todo Add param video device for 3A tuning */
-
-	BufferPool vfPool_;
-	BufferPool outPool_;
 };
 
 class CIO2Device
@@ -156,7 +152,7 @@ public:
 	{
 	}
 
-	void imguOutputBufferReady(Buffer *buffer);
+	void imguOutputBufferReady(FrameBuffer *buffer);
 	void imguInputBufferReady(FrameBuffer *buffer);
 	void cio2BufferReady(FrameBuffer *buffer);
 
@@ -691,39 +687,30 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera,
 		goto error;
 	}
 
-	/* Allocate buffers for each active stream. */
-	for (Stream *s : streams) {
-		IPU3Stream *stream = static_cast<IPU3Stream *>(s);
-		ImgUDevice::ImgUOutput *dev = stream->device_;
-
-		if (stream->memoryType() == InternalMemory)
-			ret = imgu->exportOutputBuffers(dev, &stream->bufferPool());
-		else
-			ret = imgu->importOutputBuffers(dev, &stream->bufferPool());
-		if (ret)
-			goto error;
-	}
-
 	/*
 	 * Allocate buffers also on non-active outputs; use the same number
 	 * of buffers as the active ones.
 	 */
 	if (!outStream->active_) {
-		bufferCount = vfStream->configuration().bufferCount;
-		outStream->device_->pool->createBuffers(bufferCount);
-		ret = imgu->exportOutputBuffers(outStream->device_,
-						outStream->device_->pool);
-		if (ret)
+		ImgUDevice::ImgUOutput *output = outStream->device_;
+
+		ret = output->dev->exportBuffers(bufferCount, &output->buffers);
+		if (ret < 0) {
+			LOG(IPU3, Error) << "Failed to allocate ImgU "
+					 << output->name << " buffers";
 			goto error;
+		}
 	}
 
 	if (!vfStream->active_) {
-		bufferCount = outStream->configuration().bufferCount;
-		vfStream->device_->pool->createBuffers(bufferCount);
-		ret = imgu->exportOutputBuffers(vfStream->device_,
-						vfStream->device_->pool);
-		if (ret)
+		ImgUDevice::ImgUOutput *output = vfStream->device_;
+
+		ret = output->dev->exportBuffers(bufferCount, &output->buffers);
+		if (ret < 0) {
+			LOG(IPU3, Error) << "Failed to allocate ImgU "
+					 << output->name << " buffers";
 			goto error;
+		}
 	}
 
 	return 0;
@@ -740,7 +727,7 @@ int PipelineHandlerIPU3::freeBuffers(Camera *camera,
 	IPU3CameraData *data = cameraData(camera);
 
 	data->cio2_.freeBuffers();
-	data->imgu_->freeBuffers();
+	data->imgu_->freeBuffers(data);
 
 	return 0;
 }
@@ -793,7 +780,7 @@ int PipelineHandlerIPU3::queueRequestDevice(Camera *camera, Request *request)
 
 	for (auto it : request->buffers()) {
 		IPU3Stream *stream = static_cast<IPU3Stream *>(it.first);
-		Buffer *buffer = it.second;
+		FrameBuffer *buffer = it.second;
 
 		int ret = stream->device_->dev->queueBuffer(buffer);
 		if (ret < 0)
@@ -920,9 +907,9 @@ int PipelineHandlerIPU3::registerCameras()
 					&IPU3CameraData::cio2BufferReady);
 		data->imgu_->input_->frameBufferReady.connect(data.get(),
 					&IPU3CameraData::imguInputBufferReady);
-		data->imgu_->output_.dev->bufferReady.connect(data.get(),
+		data->imgu_->output_.dev->frameBufferReady.connect(data.get(),
 					&IPU3CameraData::imguOutputBufferReady);
-		data->imgu_->viewfinder_.dev->bufferReady.connect(data.get(),
+		data->imgu_->viewfinder_.dev->frameBufferReady.connect(data.get(),
 					&IPU3CameraData::imguOutputBufferReady);
 
 		/* Create and register the Camera instance. */
@@ -971,7 +958,7 @@ void IPU3CameraData::imguInputBufferReady(FrameBuffer *buffer)
  *
  * Buffers completed from the ImgU output are directed to the application.
  */
-void IPU3CameraData::imguOutputBufferReady(Buffer *buffer)
+void IPU3CameraData::imguOutputBufferReady(FrameBuffer *buffer)
 {
 	Request *request = buffer->request();
 
@@ -1046,7 +1033,6 @@ int ImgUDevice::init(MediaDevice *media, unsigned int index)
 
 	output_.pad = PAD_OUTPUT;
 	output_.name = "output";
-	output_.pool = &outPool_;
 
 	viewfinder_.dev = V4L2VideoDevice::fromEntityName(media,
 							  name_ + " viewfinder");
@@ -1056,7 +1042,6 @@ int ImgUDevice::init(MediaDevice *media, unsigned int index)
 
 	viewfinder_.pad = PAD_VF;
 	viewfinder_.name = "viewfinder";
-	viewfinder_.pool = &vfPool_;
 
 	stat_.dev = V4L2VideoDevice::fromEntityName(media, name_ + " 3a stat");
 	ret = stat_.dev->open();
@@ -1165,68 +1150,27 @@ int ImgUDevice::configureOutput(ImgUOutput *output,
 }
 
 /**
- * \brief Export buffers from \a output to the provided \a pool
- * \param[in] output The ImgU output device
- * \param[in] pool The buffer pool where to export buffers
- *
- * Export memory buffers reserved in the video device memory associated with
- * \a output id to the buffer pool provided as argument.
- *
- * \return 0 on success or a negative error code otherwise
- */
-int ImgUDevice::exportOutputBuffers(ImgUOutput *output, BufferPool *pool)
-{
-	int ret = output->dev->exportBuffers(pool);
-	if (ret) {
-		LOG(IPU3, Error) << "Failed to export ImgU "
-				 << output->name << " buffers";
-		return ret;
-	}
-
-	return 0;
-}
-
-/**
- * \brief Reserve buffers in \a output from the provided \a pool
- * \param[in] output The ImgU output device
- * \param[in] pool The buffer pool used to reserve buffers in \a output
- *
- * Reserve a number of buffers equal to the number of buffers in \a pool
- * in the \a output device.
- *
- * \return 0 on success or a negative error code otherwise
- */
-int ImgUDevice::importOutputBuffers(ImgUOutput *output, BufferPool *pool)
-{
-	int ret = output->dev->importBuffers(pool);
-	if (ret) {
-		LOG(IPU3, Error)
-			<< "Failed to import buffer in " << output->name
-			<< " ImgU device";
-		return ret;
-	}
-
-	return 0;
-}
-
-/**
  * \brief Release buffers for all the ImgU video devices
  */
-void ImgUDevice::freeBuffers()
+void ImgUDevice::freeBuffers(IPU3CameraData *data)
 {
 	int ret;
 
-	ret = output_.dev->releaseBuffers();
-	if (ret)
-		LOG(IPU3, Error) << "Failed to release ImgU output buffers";
+	if (!data->outStream_.active_) {
+		ret = output_.dev->releaseBuffers();
+		if (ret)
+			LOG(IPU3, Error) << "Failed to release ImgU output buffers";
+	}
 
 	ret = stat_.dev->releaseBuffers();
 	if (ret)
 		LOG(IPU3, Error) << "Failed to release ImgU stat buffers";
 
-	ret = viewfinder_.dev->releaseBuffers();
-	if (ret)
-		LOG(IPU3, Error) << "Failed to release ImgU viewfinder buffers";
+	if (!data->vfStream_.active_) {
+		ret = viewfinder_.dev->releaseBuffers();
+		if (ret)
+			LOG(IPU3, Error) << "Failed to release ImgU viewfinder buffers";
+	}
 
 	ret = input_->releaseBuffers();
 	if (ret)
diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
index ba8f93e8..d669d2de 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
+++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
@@ -51,7 +51,7 @@ struct RkISP1FrameInfo {
 
 	FrameBuffer *paramBuffer;
 	FrameBuffer *statBuffer;
-	Buffer *videoBuffer;
+	FrameBuffer *videoBuffer;
 
 	bool paramFilled;
 	bool paramDequeued;
@@ -67,7 +67,6 @@ public:
 	int destroy(unsigned int frame);
 
 	RkISP1FrameInfo *find(unsigned int frame);
-	RkISP1FrameInfo *find(Buffer *buffer);
 	RkISP1FrameInfo *find(FrameBuffer *buffer);
 	RkISP1FrameInfo *find(Request *request);
 
@@ -87,7 +86,7 @@ public:
 		setDelay(QueueBuffers, -1, 10);
 	}
 
-	void bufferReady(Buffer *buffer)
+	void bufferReady(FrameBuffer *buffer)
 	{
 		/*
 		 * Calculate SOE by taking the end of DMA set by the kernel and applying
@@ -205,7 +204,7 @@ private:
 	int initLinks();
 	int createCamera(MediaEntity *sensor);
 	void tryCompleteRequest(Request *request);
-	void bufferReady(Buffer *buffer);
+	void bufferReady(FrameBuffer *buffer);
 	void paramReady(FrameBuffer *buffer);
 	void statReady(FrameBuffer *buffer);
 
@@ -243,7 +242,7 @@ RkISP1FrameInfo *RkISP1Frames::create(unsigned int frame, Request *request, Stre
 	}
 	FrameBuffer *statBuffer = pipe_->availableStatBuffers_.front();
 
-	Buffer *videoBuffer = request->findBuffer(stream);
+	FrameBuffer *videoBuffer = request->findBuffer(stream);
 	if (!videoBuffer) {
 		LOG(RkISP1, Error)
 			<< "Attempt to queue request with invalid stream";
@@ -296,26 +295,14 @@ RkISP1FrameInfo *RkISP1Frames::find(unsigned int frame)
 	return nullptr;
 }
 
-RkISP1FrameInfo *RkISP1Frames::find(Buffer *buffer)
-{
-	for (auto &itInfo : frameInfo_) {
-		RkISP1FrameInfo *info = itInfo.second;
-
-		if (info->videoBuffer == buffer)
-			return info;
-	}
-
-	LOG(RkISP1, Error) << "Can't locate info from buffer";
-	return nullptr;
-}
-
 RkISP1FrameInfo *RkISP1Frames::find(FrameBuffer *buffer)
 {
 	for (auto &itInfo : frameInfo_) {
 		RkISP1FrameInfo *info = itInfo.second;
 
 		if (info->paramBuffer == buffer ||
-		    info->statBuffer == buffer)
+		    info->statBuffer == buffer ||
+		    info->videoBuffer == buffer)
 			return info;
 	}
 
@@ -692,18 +679,9 @@ int PipelineHandlerRkISP1::allocateBuffers(Camera *camera,
 					   const std::set<Stream *> &streams)
 {
 	RkISP1CameraData *data = cameraData(camera);
-	Stream *stream = *streams.begin();
 	unsigned int count = 1;
 	int ret;
 
-	if (stream->memoryType() == InternalMemory)
-		ret = video_->exportBuffers(&stream->bufferPool());
-	else
-		ret = video_->importBuffers(&stream->bufferPool());
-
-	if (ret)
-		return ret;
-
 	unsigned int maxBuffers = 0;
 	for (const Stream *s : camera->streams())
 		maxBuffers = std::max(maxBuffers, s->configuration().bufferCount);
@@ -769,9 +747,6 @@ int PipelineHandlerRkISP1::freeBuffers(Camera *camera,
 	if (stat_->releaseBuffers())
 		LOG(RkISP1, Error) << "Failed to release stat buffers";
 
-	if (video_->releaseBuffers())
-		LOG(RkISP1, Error) << "Failed to release video buffers";
-
 	return 0;
 }
 
@@ -975,7 +950,7 @@ bool PipelineHandlerRkISP1::match(DeviceEnumerator *enumerator)
 	if (param_->open() < 0)
 		return false;
 
-	video_->bufferReady.connect(this, &PipelineHandlerRkISP1::bufferReady);
+	video_->frameBufferReady.connect(this, &PipelineHandlerRkISP1::bufferReady);
 	stat_->frameBufferReady.connect(this, &PipelineHandlerRkISP1::statReady);
 	param_->frameBufferReady.connect(this, &PipelineHandlerRkISP1::paramReady);
 
@@ -1024,7 +999,7 @@ void PipelineHandlerRkISP1::tryCompleteRequest(Request *request)
 	completeRequest(activeCamera_, request);
 }
 
-void PipelineHandlerRkISP1::bufferReady(Buffer *buffer)
+void PipelineHandlerRkISP1::bufferReady(FrameBuffer *buffer)
 {
 	ASSERT(activeCamera_);
 	RkISP1CameraData *data = cameraData(activeCamera_);
diff --git a/src/libcamera/pipeline/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo.cpp
index b72841ed..66380e29 100644
--- a/src/libcamera/pipeline/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo.cpp
@@ -42,7 +42,7 @@ public:
 	}
 
 	int init(MediaEntity *entity);
-	void bufferReady(Buffer *buffer);
+	void bufferReady(FrameBuffer *buffer);
 
 	V4L2VideoDevice *video_;
 	Stream stream_;
@@ -225,23 +225,13 @@ void PipelineHandlerUVC::freeFrameBuffers(Camera *camera, Stream *stream)
 int PipelineHandlerUVC::allocateBuffers(Camera *camera,
 					const std::set<Stream *> &streams)
 {
-	UVCCameraData *data = cameraData(camera);
-	Stream *stream = *streams.begin();
-	const StreamConfiguration &cfg = stream->configuration();
-
-	LOG(UVC, Debug) << "Requesting " << cfg.bufferCount << " buffers";
-
-	if (stream->memoryType() == InternalMemory)
-		return data->video_->exportBuffers(&stream->bufferPool());
-	else
-		return data->video_->importBuffers(&stream->bufferPool());
+	return 0;
 }
 
 int PipelineHandlerUVC::freeBuffers(Camera *camera,
 				    const std::set<Stream *> &streams)
 {
-	UVCCameraData *data = cameraData(camera);
-	return data->video_->releaseBuffers();
+	return 0;
 }
 
 int PipelineHandlerUVC::start(Camera *camera)
@@ -295,7 +285,7 @@ int PipelineHandlerUVC::processControls(UVCCameraData *data, Request *request)
 int PipelineHandlerUVC::queueRequestDevice(Camera *camera, Request *request)
 {
 	UVCCameraData *data = cameraData(camera);
-	Buffer *buffer = request->findBuffer(&data->stream_);
+	FrameBuffer *buffer = request->findBuffer(&data->stream_);
 	if (!buffer) {
 		LOG(UVC, Error)
 			<< "Attempt to queue request with invalid stream";
@@ -362,7 +352,7 @@ int UVCCameraData::init(MediaEntity *entity)
 	if (ret)
 		return ret;
 
-	video_->bufferReady.connect(this, &UVCCameraData::bufferReady);
+	video_->frameBufferReady.connect(this, &UVCCameraData::bufferReady);
 
 	/* Initialise the supported controls. */
 	const ControlInfoMap &controls = video_->controls();
@@ -402,7 +392,7 @@ int UVCCameraData::init(MediaEntity *entity)
 	return 0;
 }
 
-void UVCCameraData::bufferReady(Buffer *buffer)
+void UVCCameraData::bufferReady(FrameBuffer *buffer)
 {
 	Request *request = buffer->request();
 
diff --git a/src/libcamera/pipeline/vimc.cpp b/src/libcamera/pipeline/vimc.cpp
index 3fb5cacd..5e0f5c63 100644
--- a/src/libcamera/pipeline/vimc.cpp
+++ b/src/libcamera/pipeline/vimc.cpp
@@ -55,7 +55,7 @@ public:
 	}
 
 	int init(MediaDevice *media);
-	void bufferReady(Buffer *buffer);
+	void bufferReady(FrameBuffer *buffer);
 
 	CameraSensor *sensor_;
 	V4L2Subdevice *debayer_;
@@ -291,23 +291,13 @@ void PipelineHandlerVimc::freeFrameBuffers(Camera *camera, Stream *stream)
 int PipelineHandlerVimc::allocateBuffers(Camera *camera,
 					 const std::set<Stream *> &streams)
 {
-	VimcCameraData *data = cameraData(camera);
-	Stream *stream = *streams.begin();
-	const StreamConfiguration &cfg = stream->configuration();
-
-	LOG(VIMC, Debug) << "Requesting " << cfg.bufferCount << " buffers";
-
-	if (stream->memoryType() == InternalMemory)
-		return data->video_->exportBuffers(&stream->bufferPool());
-	else
-		return data->video_->importBuffers(&stream->bufferPool());
+	return 0;
 }
 
 int PipelineHandlerVimc::freeBuffers(Camera *camera,
 				     const std::set<Stream *> &streams)
 {
-	VimcCameraData *data = cameraData(camera);
-	return data->video_->releaseBuffers();
+	return 0;
 }
 
 int PipelineHandlerVimc::start(Camera *camera)
@@ -355,7 +345,7 @@ int PipelineHandlerVimc::processControls(VimcCameraData *data, Request *request)
 int PipelineHandlerVimc::queueRequestDevice(Camera *camera, Request *request)
 {
 	VimcCameraData *data = cameraData(camera);
-	Buffer *buffer = request->findBuffer(&data->stream_);
+	FrameBuffer *buffer = request->findBuffer(&data->stream_);
 	if (!buffer) {
 		LOG(VIMC, Error)
 			<< "Attempt to queue request with invalid stream";
@@ -447,7 +437,7 @@ int VimcCameraData::init(MediaDevice *media)
 	if (video_->open())
 		return -ENODEV;
 
-	video_->bufferReady.connect(this, &VimcCameraData::bufferReady);
+	video_->frameBufferReady.connect(this, &VimcCameraData::bufferReady);
 
 	raw_ = new V4L2VideoDevice(media->getEntityByName("Raw Capture 1"));
 	if (raw_->open())
@@ -484,7 +474,7 @@ int VimcCameraData::init(MediaDevice *media)
 	return 0;
 }
 
-void VimcCameraData::bufferReady(Buffer *buffer)
+void VimcCameraData::bufferReady(FrameBuffer *buffer)
 {
 	Request *request = buffer->request();
 
diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
index 11d68456..f6fb0974 100644
--- a/src/libcamera/pipeline_handler.cpp
+++ b/src/libcamera/pipeline_handler.cpp
@@ -472,7 +472,7 @@ int PipelineHandler::queueRequest(Camera *camera, Request *request)
  * otherwise
  */
 bool PipelineHandler::completeBuffer(Camera *camera, Request *request,
-				     Buffer *buffer)
+				     FrameBuffer *buffer)
 {
 	camera->bufferCompleted.emit(request, buffer);
 	return request->completeBuffer(buffer);
diff --git a/src/libcamera/request.cpp b/src/libcamera/request.cpp
index 4268e314..ea33736f 100644
--- a/src/libcamera/request.cpp
+++ b/src/libcamera/request.cpp
@@ -75,11 +75,6 @@ Request::Request(Camera *camera, uint64_t cookie)
 
 Request::~Request()
 {
-	for (auto it : bufferMap_) {
-		Buffer *buffer = it.second;
-		delete buffer;
-	}
-
 	delete metadata_;
 	delete controls_;
 	delete validator_;
@@ -106,18 +101,19 @@ Request::~Request()
  * \brief Retrieve the request's streams to buffers map
  *
  * Return a reference to the map that associates each Stream part of the
- * request to the Buffer the Stream output should be directed to.
+ * request to the FrameBuffer the Stream output should be directed to.
  *
- * \return The map of Stream to Buffer
+ * \return The map of Stream to FrameBuffer
  */
 
 /**
- * \brief Store a Buffer with its associated Stream in the Request
+ * \brief Add a FrameBuffer with its associated Stream to the Request
  * \param[in] stream The stream the buffer belongs to
- * \param[in] buffer The Buffer to store in the request
+ * \param[in] buffer The FrameBuffer to add to the request
  *
- * Ownership of the buffer is passed to the request. It will be deleted when
- * the request is destroyed after completing.
+ * A reference to the buffer is stored in the request. The caller is responsible
+ * for ensuring that the buffer will remain valid until the request complete
+ * callback is called.
  *
  * A request can only contain one buffer per stream. If a buffer has already
  * been added to the request for the same stream, this method returns -EEXIST.
@@ -126,7 +122,7 @@ Request::~Request()
  * \retval -EEXIST The request already contains a buffer for the stream
  * \retval -EINVAL The buffer does not reference a valid Stream
  */
-int Request::addBuffer(Stream *stream, std::unique_ptr<Buffer> buffer)
+int Request::addBuffer(Stream *stream, FrameBuffer *buffer)
 {
 	if (!stream) {
 		LOG(Request, Error) << "Invalid stream reference";
@@ -135,13 +131,13 @@ int Request::addBuffer(Stream *stream, std::unique_ptr<Buffer> buffer)
 
 	auto it = bufferMap_.find(stream);
 	if (it != bufferMap_.end()) {
-		LOG(Request, Error) << "Buffer already set for stream";
+		LOG(Request, Error) << "FrameBuffer already set for stream";
 		return -EEXIST;
 	}
 
 	buffer->request_ = this;
-	pending_.insert(buffer.get());
-	bufferMap_[stream] = buffer.release();
+	pending_.insert(buffer);
+	bufferMap_[stream] = buffer;
 
 	return 0;
 }
@@ -161,7 +157,7 @@ int Request::addBuffer(Stream *stream, std::unique_ptr<Buffer> buffer)
  * \return The buffer associated with the stream, or nullptr if the stream is
  * not part of this request
  */
-Buffer *Request::findBuffer(Stream *stream) const
+FrameBuffer *Request::findBuffer(Stream *stream) const
 {
 	auto it = bufferMap_.find(stream);
 	if (it == bufferMap_.end())
@@ -231,7 +227,7 @@ void Request::complete()
  * \return True if all buffers contained in the request have completed, false
  * otherwise
  */
-bool Request::completeBuffer(Buffer *buffer)
+bool Request::completeBuffer(FrameBuffer *buffer)
 {
 	int ret = pending_.erase(buffer);
 	ASSERT(ret == 1);