fnic: check pci_map_single() return value

the kernel prints some warnings when compiled with CONFIG_DMA_API_DEBUG.
This is because the fnic driver doesn't check the return value of
pci_map_single().

[   11.942770] scsi host12: fnic
[   11.950811] ------------[ cut here ]------------
[   11.950818] WARNING: at lib/dma-debug.c:937 check_unmap+0x47b/0x920()
[   11.950821] fnic 0000:0c:00.0: DMA-API: device driver failed to check map error[device address=0x0000002020a30040] [size=44 bytes] [mapped as single]

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed By: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
diff --git a/drivers/scsi/fnic/fnic_scsi.c b/drivers/scsi/fnic/fnic_scsi.c
index 25436cd..266b909 100644
--- a/drivers/scsi/fnic/fnic_scsi.c
+++ b/drivers/scsi/fnic/fnic_scsi.c
@@ -330,6 +330,7 @@
 	int flags;
 	u8 exch_flags;
 	struct scsi_lun fc_lun;
+	int r;
 
 	if (sg_count) {
 		/* For each SGE, create a device desc entry */
@@ -346,6 +347,12 @@
 			 io_req->sgl_list,
 			 sizeof(io_req->sgl_list[0]) * sg_count,
 			 PCI_DMA_TODEVICE);
+
+		r = pci_dma_mapping_error(fnic->pdev, io_req->sgl_list_pa);
+		if (r) {
+			printk(KERN_ERR "PCI mapping failed with error %d\n", r);
+			return SCSI_MLQUEUE_HOST_BUSY;
+		}
 	}
 
 	io_req->sense_buf_pa = pci_map_single(fnic->pdev,
@@ -353,6 +360,15 @@
 					      SCSI_SENSE_BUFFERSIZE,
 					      PCI_DMA_FROMDEVICE);
 
+	r = pci_dma_mapping_error(fnic->pdev, io_req->sense_buf_pa);
+	if (r) {
+		pci_unmap_single(fnic->pdev, io_req->sgl_list_pa,
+				sizeof(io_req->sgl_list[0]) * sg_count,
+				PCI_DMA_TODEVICE);
+		printk(KERN_ERR "PCI mapping failed with error %d\n", r);
+		return SCSI_MLQUEUE_HOST_BUSY;
+	}
+
 	int_to_scsilun(sc->device->lun, &fc_lun);
 
 	/* Enqueue the descriptor in the Copy WQ */