Hi Tomasz,
Thanks for the patch.
On Wednesday 10 October 2012 16:46:41 Tomasz Stanislawski wrote:
> From: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
>
> 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@xxxxxxxxxxx>
> Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> ---
> drivers/media/v4l2-core/videobuf2-dma-contig.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 2d661fd..571a919
> 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -493,6 +493,18 @@ 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);
> + }
Looks good to me.
> + if (!size) {
> + pr_debug("size is zero\n");
> + return ERR_PTR(-EINVAL);
> + }
Can this happen ? The vb2 core already has
/* Check if the provided plane buffer is large enough */
if (planes[plane].length < q->plane_sizes[plane]) {
ret = -EINVAL;
goto err;
}
Unless queue_setup sets plane_sizes to 0 we can't reach vb2_dc_get_userptr.
> buf = kzalloc(sizeof *buf, GFP_KERNEL);
> if (!buf)
--
Regards,
Laurent Pinchart
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