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Commit 61688b88 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Greg Kroah-Hartman
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media: videobuf-dma-contig: use dma_mmap_coherent 



[ Upstream commit b3dc3f8e49577840dc8ac8a365c5b3da4edb10b8 ]

dma_alloc_coherent does not return a physical address, but a DMA address,
which might be remapped or have an offset.  Passing the DMA address to
vm_iomap_memory is thus broken.

Use the proper dma_mmap_coherent helper instead, and stop passing
__GFP_COMP to dma_alloc_coherent, as the memory management inside the
DMA allocator is hidden from the callers and does not require it.

With this the gfp_t argument to __videobuf_dc_alloc can be removed and
hard coded to GFP_KERNEL.

Fixes: a8f3c203 ("[media] videobuf-dma-contig: add cache support")
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 9ca9d7fd

drivers/media/v4l2-core/videobuf-dma-contig.c

+8 −14
Original line number Diff line number Diff line
@@ -36,12 +36,11 @@ struct videobuf_dma_contig_memory { 


static int __videobuf_dc_alloc(struct device *dev,

			       struct videobuf_dma_contig_memory *mem,

			       unsigned long size, gfp_t flags)

			       unsigned long size)

{

	mem->size = size;

	mem->vaddr = dma_alloc_coherent(dev, mem->size,

					&mem->dma_handle, flags);



	mem->vaddr = dma_alloc_coherent(dev, mem->size, &mem->dma_handle,

					GFP_KERNEL);

	if (!mem->vaddr) {

		dev_err(dev, "memory alloc size %ld failed\n", mem->size);

		return -ENOMEM;
@@ -258,8 +257,7 @@ static int __videobuf_iolock(struct videobuf_queue *q, 
			return videobuf_dma_contig_user_get(mem, vb);



		/* allocate memory for the read() method */

		if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(vb->size),

					GFP_KERNEL))

		if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(vb->size)))

			return -ENOMEM;

		break;

	case V4L2_MEMORY_OVERLAY:
@@ -295,22 +293,18 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q, 
	BUG_ON(!mem);

	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);



	if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(buf->bsize),

				GFP_KERNEL | __GFP_COMP))

	if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(buf->bsize)))

		goto error;



	/* Try to remap memory */

	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);



	/* the "vm_pgoff" is just used in v4l2 to find the

	 * corresponding buffer data structure which is allocated

	 * earlier and it does not mean the offset from the physical

	 * buffer start address as usual. So set it to 0 to pass

	 * the sanity check in vm_iomap_memory().

	 * the sanity check in dma_mmap_coherent().

	 */

	vma->vm_pgoff = 0;



	retval = vm_iomap_memory(vma, mem->dma_handle, mem->size);

	retval = dma_mmap_coherent(q->dev, vma, mem->vaddr, mem->dma_handle,

				   mem->size);

	if (retval) {

		dev_err(q->dev, "mmap: remap failed with error %d. ",

			retval);