nvme-pci: DMA unmap the correct regions in nvme_free_sgls

The call to nvme_free_sgls() in nvme_unmap_data() has the sg_list and sge
parameters swapped.  This wasn't noticed by the compiler because both share
the same type.  On a Xen PV hardware domain, and possibly any other
architectures that takes that path, this leads to corruption of the NVMe
contents.

Fixes: f0887e2 ("nvme-pci: create common sgl unmapping helper")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: royger

drivers/nvme/host/pci.c

@@ -806,8 +806,8 @@ static void nvme_unmap_data(struct request *req)
 	if (!blk_rq_dma_unmap(req, dma_dev, &iod->dma_state, iod->total_len,
 			      map)) {
 		if (nvme_pci_cmd_use_sgl(&iod->cmd))
-			nvme_free_sgls(req, iod->descriptors[0],
-				       &iod->cmd.common.dptr.sgl, attrs);
+			nvme_free_sgls(req, &iod->cmd.common.dptr.sgl,
+			               iod->descriptors[0], attrs);
 		else
 			nvme_free_prps(req, attrs);
 	}