[libcamera-devel] [RFC PATCH 09/10] libcamera: pipeline: raspberrypi: DmaHeaps: Use ScopedFD for a file descriptor

[Laurent Pinchart]

Hi Hiro,

Thank you for the patch.

On Thu, Apr 15, 2021 at 05:38:42PM +0900, Hirokazu Honda wrote:
> DmaHeaps owns a file descriptor for a dma handle. It should be
> managed by ScopedFD to avoid the leakage. Furthermore,
> DmaHeaps::alloc() creates a new file descriptor and the returned
> file descriptor is owned by a caller. This also clarifies it by
> changing the returned value to ScopedFD.
> 
> Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
> ---
>  .../pipeline/raspberrypi/dma_heaps.cpp        | 23 ++++++++-----------
>  .../pipeline/raspberrypi/dma_heaps.h          | 10 ++++----
>  .../pipeline/raspberrypi/raspberrypi.cpp      |  7 ++++--
>  3 files changed, 21 insertions(+), 19 deletions(-)
> 
> diff --git a/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> index 4d5dd6cb..d5b000b8 100644
> --- a/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> @@ -35,7 +35,6 @@ LOG_DECLARE_CATEGORY(RPI)
>  namespace RPi {
>  
>  DmaHeap::DmaHeap()
> -	: dmaHeapHandle_(-1)
>  {
>  	for (const char *name : heapNames) {
>  		int ret = ::open(name, O_RDWR, 0);
> @@ -46,49 +45,47 @@ DmaHeap::DmaHeap()
>  			continue;
>  		}
>  
> -		dmaHeapHandle_ = ret;
> +		dmaHeapHandle_ = ScopedFD(ret);
>  		break;
>  	}
>  
> -	if (dmaHeapHandle_ < 0)
> +	if (!dmaHeapHandle_.isValid())
>  		LOG(RPI, Error) << "Could not open any dmaHeap device";
>  }
>  
>  DmaHeap::~DmaHeap()
>  {
> -	if (dmaHeapHandle_ > -1)
> -		::close(dmaHeapHandle_);
>  }
>  
> -FileDescriptor DmaHeap::alloc(const char *name, std::size_t size)
> +ScopedFD DmaHeap::alloc(const char *name, std::size_t size)
>  {
>  	int ret;
>  
>  	if (!name)
> -		return FileDescriptor();
> +		return ScopedFD();
>  
>  	struct dma_heap_allocation_data alloc = {};
>  
>  	alloc.len = size;
>  	alloc.fd_flags = O_CLOEXEC | O_RDWR;
>  
> -	ret = ::ioctl(dmaHeapHandle_, DMA_HEAP_IOCTL_ALLOC, &alloc);
> +	ret = ::ioctl(dmaHeapHandle_.get(), DMA_HEAP_IOCTL_ALLOC, &alloc);
>  
>  	if (ret < 0) {
>  		LOG(RPI, Error) << "dmaHeap allocation failure for "
>  				<< name;
> -		return FileDescriptor();
> +		return ScopedFD();
>  	}
>  
> -	ret = ::ioctl(alloc.fd, DMA_BUF_SET_NAME, name);
> +	ScopedFD allocFd(alloc.fd);
> +	ret = ::ioctl(allocFd.get(), DMA_BUF_SET_NAME, name);
>  	if (ret < 0) {
>  		LOG(RPI, Error) << "dmaHeap naming failure for "
>  				<< name;
> -		::close(alloc.fd);
> -		return FileDescriptor();
> +		return ScopedFD();
>  	}
>  
> -	return FileDescriptor(std::move(alloc.fd));
> +	return allocFd;
>  }
>  
>  } /* namespace RPi */
> diff --git a/src/libcamera/pipeline/raspberrypi/dma_heaps.h b/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> index 79f39c51..c49772df 100644
> --- a/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> +++ b/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> @@ -7,7 +7,9 @@
>  #ifndef __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__
>  #define __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__
>  
> -#include <libcamera/file_descriptor.h>
> +#include <cstddef>
> +
> +#include <libcamera/scoped_file_descriptor.h>
>  
>  namespace libcamera {
>  
> @@ -18,11 +20,11 @@ class DmaHeap
>  public:
>  	DmaHeap();
>  	~DmaHeap();
> -	bool isValid() const { return dmaHeapHandle_ > -1; }
> -	FileDescriptor alloc(const char *name, std::size_t size);
> +	bool isValid() const { return dmaHeapHandle_.isValid(); }
> +	ScopedFD alloc(const char *name, std::size_t size);
>  
>  private:
> -	int dmaHeapHandle_;
> +	ScopedFD dmaHeapHandle_;
>  };
>  
>  } /* namespace RPi */
> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> index f22e286e..0075fdb1 100644
> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> @@ -1256,10 +1256,13 @@ int RPiCameraData::configureIPA(const CameraConfiguration *config)
>  
>  	/* Allocate the lens shading table via dmaHeap and pass to the IPA. */
>  	if (!lsTable_.isValid()) {
> -		lsTable_ = dmaHeap_.alloc("ls_grid", ipa::RPi::MaxLsGridSize);
> -		if (!lsTable_.isValid())
> +		ScopedFD scopedFD =
> +			dmaHeap_.alloc("ls_grid", ipa::RPi::MaxLsGridSize);
> +		if (!scopedFD.isValid())
>  			return -ENOMEM;
>  
> +		lsTable_ = FileDescriptor(scopedFD.release());

This isn't very nice. One option could be to add a FileDescriptor
constructor that takes a ScopedFD. What do you think ?

> +
>  		/* Allow the IPA to mmap the LS table via the file descriptor. */
>  		/*
>  		 * \todo Investigate if mapping the lens shading table buffer

-- 
Regards,

Laurent Pinchart