[PATCHv8 22/26] media: vb2: fail if user ptr buffer is not correctly aligned

[Tomasz Stanislawski]

From: Marek Szyprowski <m.szyprowski at samsung.com>

Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
---
 drivers/media/video/videobuf2-dma-contig.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c
index d44766e..11f4a46 100644
--- a/drivers/media/video/videobuf2-dma-contig.c
+++ b/drivers/media/video/videobuf2-dma-contig.c
@@ -498,6 +498,16 @@ 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();
+
+	/*
+	 * DMA transfers are not reliable to buffers which
+	 * are not cache line aligned!
+	 */
+	if (vaddr & (dma_align - 1)) {
+		pr_err("userptr must be aligned to %lu bytes\n", dma_align);
+		return ERR_PTR(-EINVAL);
+	}
 
 	buf = kzalloc(sizeof *buf, GFP_KERNEL);
 	if (!buf)
-- 
1.7.9.5