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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: Kundan Kumar <kundan.kumar@samsung.com>,
	Christoph Hellwig <hch@lst.de>,
	Sagi Grimberg <sagi@grimberg.me>,
	Keith Busch <kbusch@kernel.org>,
	Sasha Levin <sashal@kernel.org>,
	linux-nvme@lists.infradead.org
Subject: [PATCH AUTOSEL 6.8 04/18] nvme: adjust multiples of NVME_CTRL_PAGE_SIZE in offset
Date: Wed,  5 Jun 2024 08:02:54 -0400
Message-ID: <20240605120319.2966627-4-sashal@kernel.org>
In-Reply-To: <20240605120319.2966627-1-sashal@kernel.org>
References: <20240605120319.2966627-1-sashal@kernel.org>
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From: Kundan Kumar <kundan.kumar@samsung.com>

[ Upstream commit 1bd293fcf3af84674e82ed022c049491f3768840 ]

bio_vec start offset may be relatively large particularly when large
folio gets added to the bio. A bigger offset will result in avoiding the
single-segment mapping optimization and end up using expensive
mempool_alloc further.

Rather than using absolute value, adjust bv_offset by
NVME_CTRL_PAGE_SIZE while checking if segment can be fitted into one/two
PRP entries.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kundan Kumar <kundan.kumar@samsung.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/host/pci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 710043086dffa..102a9fb0c65ff 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -778,7 +778,8 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 		struct bio_vec bv = req_bvec(req);
 
 		if (!is_pci_p2pdma_page(bv.bv_page)) {
-			if (bv.bv_offset + bv.bv_len <= NVME_CTRL_PAGE_SIZE * 2)
+			if ((bv.bv_offset & (NVME_CTRL_PAGE_SIZE - 1)) +
+			     bv.bv_len <= NVME_CTRL_PAGE_SIZE * 2)
 				return nvme_setup_prp_simple(dev, req,
 							     &cmnd->rw, &bv);
 
-- 
2.43.0