[libcamera-devel] [PATCH v4 17/22] libcamera: pipeline: raspberrypi: DmaHeaps: Use UniqueFD for a file descriptor

[Laurent Pinchart]

Hi Jacopo,

On Tue, Nov 30, 2021 at 09:06:55AM +0100, Jacopo Mondi wrote:
> On Tue, Nov 30, 2021 at 05:38:15AM +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>
> > Reviewed-by: Hirokazu Honda <hiroh at chromium.org>
> > ---
> > 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);
> >  		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>
> > +
> > +#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 d82cb30f0e77..d4f248a799e5 100644
> > --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > @@ -1382,10 +1382,12 @@ 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));
> 
> As lsTable_ is initialized once, why going through a UniqueFD and then
> a FileDescriptor ?

Good point. I'll change this to

	lsTable_ = FileDescriptor(dmaHeap_.alloc("ls_grid", ipa::RPi::MaxLsGridSize));
	if (!lsTable_.isValid())
		return -ENOMEM;

> Otherwise
> Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> 
> > +
> >  		/* Allow the IPA to mmap the LS table via the file descriptor. */
> >  		/*
> >  		 * \todo Investigate if mapping the lens shading table buffer

-- 
Regards,

Laurent Pinchart