media: saa7146: use sg_dma_len when building pgtable

[ Upstream commit e56429b0 ]

The new AMD IOMMU DMA implementation concatenates sglist entries under
certain conditions, and because saa7146 accessed the length member
directly, it did not support this scenario.

This fixes IO_PAGE_FAULTs by using the sg_dma_len macro.

Fixes: be62dbf5 ("iommu/amd: Convert AMD iommu driver to the dma-iommu api")
Signed-off-by: Tasos Sahanidis <tasos@tasossah.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/media/common/saa7146/saa7146_core.c

@@ -253,7 +253,7 @@ int saa7146_pgtable_build_single(struct pci_dev *pci, struct saa7146_pgtable *pt
 			 i, sg_dma_address(list), sg_dma_len(list),
 			 list->offset);
 */
-		for (p = 0; p * 4096 < list->length; p++, ptr++) {
+		for (p = 0; p * 4096 < sg_dma_len(list); p++, ptr++) {
 			*ptr = cpu_to_le32(sg_dma_address(list) + p * 4096);
 			nr_pages++;
 		}

drivers/media/common/saa7146/saa7146_video.c

@@ -247,9 +247,8 @@ static int saa7146_pgtable_build(struct saa7146_dev *dev, struct saa7146_buf *bu
 
 		/* walk all pages, copy all page addresses to ptr1 */
 		for (i = 0; i < length; i++, list++) {
-			for (p = 0; p * 4096 < list->length; p++, ptr1++) {
+			for (p = 0; p * 4096 < sg_dma_len(list); p++, ptr1++)
 				*ptr1 = cpu_to_le32(sg_dma_address(list) - list->offset);
-			}
 		}
 /*
 		ptr1 = pt1->cpu;