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From:   Wang Lu <wanglu@dapustor.com>
To:     bhelgaas@google.com
Cc:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        Wang Lu <wanglu@dapustor.com>
Subject: [PATCH] PCI/P2PDMA: fix the wrong dma address calculation when map sg
Date:   Thu,  9 Sep 2021 11:25:28 +0800
Message-Id: <20210909032528.24517-1-wanglu@dapustor.com>
Feedback-ID: bizesmtp:dapustor.com:qybgforeign:qybgforeign5
Precedence: bulk

The bus offset is bus address - physical address,
so the calculation in __pci_p2pdma_map_sg should be:
bus address = physical address + bus offset.

Signed-off-by: Wang Lu <wanglu@dapustor.com>
---
 drivers/pci/p2pdma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 50cdde3e9a8b..327882638b30 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -874,7 +874,7 @@ static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap,
 	int i;
 
 	for_each_sg(sg, s, nents, i) {
-		s->dma_address = sg_phys(s) - p2p_pgmap->bus_offset;
+		s->dma_address = sg_phys(s) + p2p_pgmap->bus_offset;
 		sg_dma_len(s) = s->length;
 	}
 
-- 
2.17.1