From 3a19407913e8e43d6b799a59bc0f6cae889b5446 Mon Sep 17 00:00:00 2001
From: Wang Lu <wanglu@dapustor.com>
Date: Thu, 9 Sep 2021 11:25:28 +0800
Subject: [PATCH] PCI/P2PDMA: Apply bus offset correctly in DMA address
 calculation
Git-commit: 3a19407913e8e43d6b799a59bc0f6cae889b5446
References: git-fixes
Patch-mainline: v5.16-rc1

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

Correct the dma_address computation in __pci_p2pdma_map_sg().

Link: https://lore.kernel.org/r/20210909032528.24517-1-wanglu@dapustor.com
Signed-off-by: Wang Lu <wanglu@dapustor.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Oliver Neukum <oneukum@suse.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;
 	}
 
-- 
2.26.2