[PATCH 1/2] nvme-pci: fix freeing single sgl

[Keith Busch]

From: Keith Busch <kbusch at kernel.org>

There may only be a single DMA mapped entry from multiple physical
segments, which means we don't allocate a separte SGL list. Check the
number of allocations prior to know if we need to free something.

Freeing a single list allocation is the same for both PRP and SGL
usages, so we don't need to check the use_sgl flag anymore.

Fixes: 01df742d8c5c0 ("nvme-pci: remove SGL segment descriptors")
Reported-by: Niklas Schnelle <schnelle at linux.ibm.com>
Signed-off-by: Keith Busch <kbusch at kernel.org>
---
Niklas,
This is a little different than the one you tested, so I didn't include
your "Tested-by". I'm confident this is patch still fixes the issue,
though.

 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 a331fbfa9a667..47d6b0023e3a8 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -556,7 +556,7 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
 	if (iod->nr_allocations == 0)
 		dma_pool_free(dev->prp_small_pool, iod->list[0].sg_list,
 			      iod->first_dma);
-	else if (iod->use_sgl)
+	else if (iod->nr_allocations == 1)
 		dma_pool_free(dev->prp_page_pool, iod->list[0].sg_list,
 			      iod->first_dma);
 	else
-- 
2.30.2