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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Tasos Sahanidis <tasos@tasossah.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.12 352/677] media: saa7134: use sg_dma_len when building pgtable
Date:   Wed, 12 May 2021 16:46:38 +0200
Message-Id: <20210512144849.007739070@linuxfoundation.org>
In-Reply-To: <20210512144837.204217980@linuxfoundation.org>
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From: Tasos Sahanidis <tasos@tasossah.com>

[ Upstream commit 4e1cb753c04d74e06d7ca826ea0bcb02526af03e ]

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 <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/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);
 	}
-- 
2.30.2