[PATCH] media: saa7134: use sg_dma_len when building pgtable

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From: Tasos Sahanidis <hidden>
Date: 2021-03-04 00:32:33
Subsystem: media input infrastructure (v4l/dvb), saa7134 video4linux driver, the rest · Maintainers: Mauro Carvalho Chehab, Linus Torvalds

The new AMD IOMMU DMA implementation concatenates sglist entries under
certain conditions, and because saa7134 accessed the length member
directly, it did not support this scenario.

This fixes IO_PAGE_FAULTs and choppy DMA audio by using the
sg_dma_len macro.

Fixes: be62dbf554c5 ("iommu/amd: Convert AMD iommu driver to the dma-iommu api")
Signed-off-by: Tasos Sahanidis <redacted>
---
 drivers/media/pci/saa7134/saa7134-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/pci/saa7134/saa7134-core.c b/drivers/media/pci/saa7134/saa7134-core.c
index 391572a6ec76..efb757d5168a 100644
--- a/drivers/media/pci/saa7134/saa7134-core.c
+++ b/drivers/media/pci/saa7134/saa7134-core.c
@@ -243,7 +243,7 @@ int saa7134_pgtable_build(struct pci_dev *pci, struct saa7134_pgtable *pt,
 
 	ptr = pt->cpu + startpage;
 	for (i = 0; i < length; i++, list = sg_next(list)) {
-		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) +
 						list->offset + p * 4096);
 	}
-- 
2.25.1
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