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[media] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned

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The DMA transfer must be aligned to a specific value. If userptr is not aligned
to DMA requirements then unexpected corruptions of the memory may occur before
or after a buffer.  To prevent such situations, all unligned userptr buffers
are rejected at VIDIOC_QBUF.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Marek Szyprowski 2012-06-12 10:18:16 -03:00 committed by Mauro Carvalho Chehab
parent 67a5d0cebf
commit d81e870d5a
1 changed files with 12 additions and 0 deletions
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12
drivers/media/v4l2-core/videobuf2-dma-contig.c
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@ -491,6 +491,18 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
struct vm_area_struct *vma;
struct sg_table *sgt;
unsigned long contig_size;
unsigned long dma_align = dma_get_cache_alignment();
/* Only cache aligned DMA transfers are reliable */
if (!IS_ALIGNED(vaddr | size, dma_align)) {
pr_debug("user data must be aligned to %lu bytes\n", dma_align);
return ERR_PTR(-EINVAL);
}
if (!size) {
pr_debug("size is zero\n");
return ERR_PTR(-EINVAL);
}
buf = kzalloc(sizeof *buf, GFP_KERNEL);
if (!buf)