nvme-pci: fix leak on sgl setup error

We need to free the descriptor that was allocated. We also don't
necessarily need to unmap each sgl entry, which was previously being
attempted unconditionally.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Author: keithbusch

drivers/nvme/host/pci.c

@@ -935,7 +935,7 @@ static blk_status_t nvme_pci_setup_data_sgl(struct request *req,
 
 	nvme_pci_sgl_set_seg(&iod->cmd.common.dptr.sgl, sgl_dma, mapped);
 	if (unlikely(iter->status))
-		nvme_free_sgls(req);
+		nvme_unmap_data(req);
 	return iter->status;
 }