2021-04-09 18:21:27

by Niklas Cassel

Subject: [PATCH] nvme-pci: don't simple map sgl when sgls are disabled

From: Niklas Cassel <[email protected]>

According to the module parameter description for sgl_threshold,
a value of 0 means that SGLs are disabled.

If SGLs are disabled, we should respect that, even for the case
where the request is made up of a single physical segment.

Fixes: 297910571f08 ("nvme-pci: optimize mapping single segment requests using SGLs")
Signed-off-by: Niklas Cassel <[email protected]>
---
drivers/nvme/host/pci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index d47bb18b976a..b06e685d1250 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -854,7 +854,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
return nvme_setup_prp_simple(dev, req,
&cmnd->rw, &bv);

- if (iod->nvmeq->qid &&
+ if (iod->nvmeq->qid && sgl_threshold &&
dev->ctrl.sgls & ((1 << 0) | (1 << 1)))
return nvme_setup_sgl_simple(dev, req,
&cmnd->rw, &bv);
--
2.30.2

2021-04-12 07:50:33

by Christoph Hellwig

Subject: Re: [PATCH] nvme-pci: don't simple map sgl when sgls are disabled

Thanks,

applied to nvme-5.13.