From: Marek Szyprowski Date: Tue, 12 Jun 2012 13:18:16 +0000 (-0300) Subject: [media] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=d81e870d5afa1b0a95ea94c4052d3c7e973fae8c;p=openwrt%2Fstaging%2Fblogic.git [media] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned 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 Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index b35f38e9f2d7..27de1bb731db 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -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)