Hi Tomasz,
Thanks for the patch.
On Tuesday 02 October 2012 16:27:33 Tomasz Stanislawski wrote:
From: Marek Szyprowski m.szyprowski@samsung.com
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
drivers/media/video/videobuf2-dma-contig.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index b4d287a..55f8c80 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -494,6 +494,13 @@ 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_err("user data must be aligned to %lu bytes\n", dma_align);return ERR_PTR(-EINVAL);
Do you think EFAULT would be more descriptive ? EINVAL is already used quite extensively. We could then possibly turn pr_err() into pr_dbg() to avoid flooding the kernel log.
}
buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf)