From: Kevin Hao <haokexin@gmail.com>
Date: Fri, 18 Oct 2019 10:53:14 +0800
Subject: nvme-pci: Set the prp2 correctly when using more than 4k page
Git-commit: a4f40484e7f1dff56bb9f286cc59ffa36e0259eb
Patch-mainline: 5.4-rc4
References: bnc#1151927 5.3.8

In the current code, the nvme is using a fixed 4k PRP entry size,
but if the kernel use a page size which is more than 4k, we should
consider the situation that the bv_offset may be larger than the
dev->ctrl.page_size. Otherwise we may miss setting the prp2 and then
cause the command can't be executed correctly.

Fixes: dff824b2aadb ("nvme-pci: optimize mapping of small single segment requests")
Cc: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/nvme/host/pci.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -771,7 +771,8 @@ static blk_status_t nvme_setup_prp_simpl
 		struct bio_vec *bv)
 {
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
-	unsigned int first_prp_len = dev->ctrl.page_size - bv->bv_offset;
+	unsigned int offset = bv->bv_offset & (dev->ctrl.page_size - 1);
+	unsigned int first_prp_len = dev->ctrl.page_size - offset;
 
 	iod->first_dma = dma_map_bvec(dev->dev, bv, rq_dma_dir(req), 0);
 	if (dma_mapping_error(dev->dev, iod->first_dma))