[libcamera-devel] [PATCH v3 15/17] libcamera: pipeline: raspberrypi: DmaHeaps: Use UniqueFD for a file descriptor

[Jacopo Mondi]

Hi Laurent

On Mon, Nov 29, 2021 at 01:57:50AM +0200, Laurent Pinchart wrote:
> From: Hirokazu Honda <hiroh at chromium.org>
>
> Manages a file descriptor owned by DmaHeaps for a dma handle by
> UniqueFD. 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 UniqueFD.
>
> Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
> Changes since v2:
>
> - Use default destructor
> - Return {}
> ---
>  .../pipeline/raspberrypi/dma_heaps.cpp        | 28 ++++++++-----------
>  .../pipeline/raspberrypi/dma_heaps.h          | 10 ++++---
>  .../pipeline/raspberrypi/raspberrypi.cpp      |  6 ++--
>  3 files changed, 21 insertions(+), 23 deletions(-)
>
> diff --git a/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> index 573ea11de607..69831dabbe75 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 +45,44 @@ DmaHeap::DmaHeap()
>  			continue;
>  		}
>
> -		dmaHeapHandle_ = ret;
> +		dmaHeapHandle_ = UniqueFD(ret);

In this series you have mostly used

                dmaHeapHandle_ = UniqueFD(::open(name, O_RDWR, 0));
                if (dmaHeapHandle_.isValid())

but it's ok the way it is

>  		break;
>  	}
>
> -	if (dmaHeapHandle_ < 0)
> +	if (!dmaHeapHandle_.isValid())
>  		LOG(RPI, Error) << "Could not open any dmaHeap device";
>  }
>
> -DmaHeap::~DmaHeap()
> -{
> -	if (dmaHeapHandle_ > -1)
> -		::close(dmaHeapHandle_);
> -}
> +DmaHeap::~DmaHeap() = default;
>
> -FileDescriptor DmaHeap::alloc(const char *name, std::size_t size)
> +UniqueFD DmaHeap::alloc(const char *name, std::size_t size)
>  {
>  	int ret;
>
>  	if (!name)
> -		return FileDescriptor();
> +		return {};
>
>  	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 {};
>  	}
>
> -	ret = ::ioctl(alloc.fd, DMA_BUF_SET_NAME, name);
> +	UniqueFD 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 {};
>  	}
>
> -	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 57beaeb2e48a..d38f41eae1a2 100644
> --- a/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> +++ b/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> @@ -7,7 +7,9 @@
>
>  #pragma once
>
> -#include <libcamera/base/file_descriptor.h>
> +#include <stddef.h>

what for ?

> +
> +#include <libcamera/base/unique_fd.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(); }
> +	UniqueFD alloc(const char *name, std::size_t size);
>
>  private:
> -	int dmaHeapHandle_;
> +	UniqueFD dmaHeapHandle_;
>  };
>
>  } /* namespace RPi */
> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> index 7526edf774a2..ffa51a0c65ca 100644
> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> @@ -1361,10 +1361,12 @@ 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())
> +		UniqueFD fd = dmaHeap_.alloc("ls_grid", ipa::RPi::MaxLsGridSize);
> +		if (!fd.isValid())
>  			return -ENOMEM;
>
> +		lsTable_ = FileDescriptor(std::move(fd));
> +
>  		/* Allow the IPA to mmap the LS table via the file descriptor. */
>  		/*
>  		 * \todo Investigate if mapping the lens shading table buffer
> --
> Regards,
>
> Laurent Pinchart
>