linux-kernel - [PATCH AUTOSEL 5.2 84/85] dma-direct: correct the physical addr in dma_direct_sync_sg_for

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Date:   Fri, 26 Jul 2019 09:39:34 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Fugang Duan <fugang.duan@....com>,
        Robin Murphy <robin.murphy@....com>,
        Christoph Hellwig <hch@....de>,
        Sasha Levin <sashal@...nel.org>,
        iommu@...ts.linux-foundation.org
Subject: [PATCH AUTOSEL 5.2 84/85] dma-direct: correct the physical addr in dma_direct_sync_sg_for_cpu/device

From: Fugang Duan <fugang.duan@....com>

[ Upstream commit 449fa54d6815be8c2c1f68fa9dbbae9384a7c03e ]

dma_map_sg() may use swiotlb buffer when the kernel command line includes
"swiotlb=force" or the dma_addr is out of dev->dma_mask range.  After
DMA complete the memory moving from device to memory, then user call
dma_sync_sg_for_cpu() to sync with DMA buffer, and copy the original
virtual buffer to other space.

So dma_direct_sync_sg_for_cpu() should use swiotlb physical addr, not
the original physical addr from sg_phys(sg).

dma_direct_sync_sg_for_device() also has the same issue, correct it as
well.

Fixes: 55897af63091("dma-direct: merge swiotlb_dma_ops into the dma_direct code")
Signed-off-by: Fugang Duan <fugang.duan@....com>
Reviewed-by: Robin Murphy <robin.murphy@....com>
Signed-off-by: Christoph Hellwig <hch@....de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 kernel/dma/direct.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 2c2772e9702a..2c6d51a62251 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -231,12 +231,14 @@ void dma_direct_sync_sg_for_device(struct device *dev,
 	int i;
 
 	for_each_sg(sgl, sg, nents, i) {
-		if (unlikely(is_swiotlb_buffer(sg_phys(sg))))
-			swiotlb_tbl_sync_single(dev, sg_phys(sg), sg->length,
+		phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
+
+		if (unlikely(is_swiotlb_buffer(paddr)))
+			swiotlb_tbl_sync_single(dev, paddr, sg->length,
 					dir, SYNC_FOR_DEVICE);
 
 		if (!dev_is_dma_coherent(dev))
-			arch_sync_dma_for_device(dev, sg_phys(sg), sg->length,
+			arch_sync_dma_for_device(dev, paddr, sg->length,
 					dir);
 	}
 }
@@ -268,11 +270,13 @@ void dma_direct_sync_sg_for_cpu(struct device *dev,
 	int i;
 
 	for_each_sg(sgl, sg, nents, i) {
+		phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
+
 		if (!dev_is_dma_coherent(dev))
-			arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
-	
-		if (unlikely(is_swiotlb_buffer(sg_phys(sg))))
-			swiotlb_tbl_sync_single(dev, sg_phys(sg), sg->length, dir,
+			arch_sync_dma_for_cpu(dev, paddr, sg->length, dir);
+
+		if (unlikely(is_swiotlb_buffer(paddr)))
+			swiotlb_tbl_sync_single(dev, paddr, sg->length, dir,
 					SYNC_FOR_CPU);
 	}
 
-- 
2.20.1