firewire: sbp2: fix DMA mapping leak on the failure path

Reported-by: FUJITA Tomonori <[e-mail]>
who also provided a first version of the fix.

Signed-off-by: Stefan Richter <[e-mail]>

drivers/firewire/fw-sbp2.c

···
 	.id_table = sbp2_id_table,
 };
 
+static void sbp2_unmap_scatterlist(struct device *card_device,
+				   struct sbp2_command_orb *orb)
+{
+	if (scsi_sg_count(orb->cmd))
+		dma_unmap_sg(card_device, scsi_sglist(orb->cmd),
+			     scsi_sg_count(orb->cmd),
+			     orb->cmd->sc_data_direction);
+
+	if (orb->request.misc & cpu_to_be32(COMMAND_ORB_PAGE_TABLE_PRESENT))
+		dma_unmap_single(card_device, orb->page_table_bus,
+				 sizeof(orb->page_table), DMA_TO_DEVICE);
+}
+
 static unsigned int
 sbp2_status_to_sense_data(u8 *sbp2_status, u8 *sense_data)
 {
···
 
 	dma_unmap_single(device->card->device, orb->base.request_bus,
 			 sizeof(orb->request), DMA_TO_DEVICE);
-
-	if (scsi_sg_count(orb->cmd) > 0)
-		dma_unmap_sg(device->card->device, scsi_sglist(orb->cmd),
-			     scsi_sg_count(orb->cmd),
-			     orb->cmd->sc_data_direction);
-
-	if (orb->page_table_bus != 0)
-		dma_unmap_single(device->card->device, orb->page_table_bus,
-				 sizeof(orb->page_table), DMA_TO_DEVICE);
+	sbp2_unmap_scatterlist(device->card->device, orb);
 
 	orb->cmd->result = result;
 	orb->done(orb->cmd);
···
 	orb->base.request_bus =
 		dma_map_single(device->card->device, &orb->request,
 			       sizeof(orb->request), DMA_TO_DEVICE);
-	if (dma_mapping_error(device->card->device, orb->base.request_bus))
+	if (dma_mapping_error(device->card->device, orb->base.request_bus)) {
+		sbp2_unmap_scatterlist(device->card->device, orb);
 		goto out;
+	}
 
 	sbp2_send_orb(&orb->base, lu, lu->tgt->node_id, generation,
 		      lu->command_block_agent_address + SBP2_ORB_POINTER);