nvme: set dma alignment to dword

[ Upstream commit 52fde2c07da606f3f120af4f734eadcfb52b04be ]

The nvme specification only requires qword alignment for segment
descriptors, and the driver already guarantees that. The spec has always
allowed user data to be dword aligned, which is what the queue's
attribute is for, so relax the alignment requirement to that value.

While we could allow byte alignment for some controllers when using
SGLs, we still need to support PRP, and that only allows dword.

Fixes: 3b2a1ebceba3 ("nvme: set dma alignment to qword")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 711b894..af355b9 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1777,7 +1777,7 @@ static void nvme_set_queue_limits(struct nvme_ctrl *ctrl,
                blk_queue_max_segments(q, min_t(u32, max_segments, USHRT_MAX));
        }
        blk_queue_virt_boundary(q, NVME_CTRL_PAGE_SIZE - 1);
-       blk_queue_dma_alignment(q, 7);
+       blk_queue_dma_alignment(q, 3);
        blk_queue_write_cache(q, vwc, vwc);
 }