[PATCH] nvme: set dma alignment to 3

Keith Busch
2022-05-04T18:43:41Z

From: Keith Busch <kbusch@kernel.org>

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>
---
drivers/nvme/host/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index bea054565eed..0a6fb515a339 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1771,7 +1771,7 @@ 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);
}

--
2.30.2