[SCSI] buslogic: Added check for DMA mapping errors

Added check for DMA mapping errors for request sense data
buffer. Checking for mapping error can avoid potential wild
writes. This patch was prompted by the warning from
dma_unmap when kernel is compiled with CONFIG_DMA_API_DEBUG.
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/BusLogic.c

@@ -26,8 +26,8 @@
 
 */
 
-#define blogic_drvr_version		"2.1.16"
-#define blogic_drvr_date		"18 July 2002"
+#define blogic_drvr_version		"2.1.17"
+#define blogic_drvr_date		"12 September 2013"
 
 #include <linux/module.h>
 #include <linux/init.h>
@@ -311,12 +311,14 @@ static struct blogic_ccb *blogic_alloc_ccb(struct blogic_adapter *adapter)
   caller.
 */
 
-static void blogic_dealloc_ccb(struct blogic_ccb *ccb)
+static void blogic_dealloc_ccb(struct blogic_ccb *ccb, int dma_unmap)
 {
 	struct blogic_adapter *adapter = ccb->adapter;
 
-	scsi_dma_unmap(ccb->command);
-	pci_unmap_single(adapter->pci_device, ccb->sensedata,
+	if (ccb->command != NULL)
+		scsi_dma_unmap(ccb->command);
+	if (dma_unmap)
+		pci_unmap_single(adapter->pci_device, ccb->sensedata,
 			 ccb->sense_datalen, PCI_DMA_FROMDEVICE);
 
 	ccb->command = NULL;
@@ -2762,8 +2764,8 @@ static void blogic_process_ccbs(struct blogic_adapter *adapter)
 			/*
 			   Place CCB back on the Host Adapter's free list.
 			 */
-			blogic_dealloc_ccb(ccb);
-#if 0				/* this needs to be redone different for new EH */
+			blogic_dealloc_ccb(ccb, 1);
+#if 0			/* this needs to be redone different for new EH */
 			/*
 			   Bus Device Reset CCBs have the command field
 			   non-NULL only when a Bus Device Reset was requested
@@ -2791,7 +2793,7 @@ static void blogic_process_ccbs(struct blogic_adapter *adapter)
 				if (ccb->status == BLOGIC_CCB_RESET &&
 						ccb->tgt_id == tgt_id) {
 					command = ccb->command;
-					blogic_dealloc_ccb(ccb);
+					blogic_dealloc_ccb(ccb, 1);
 					adapter->active_cmds[tgt_id]--;
 					command->result = DID_RESET << 16;
 					command->scsi_done(command);
@@ -2862,7 +2864,7 @@ static void blogic_process_ccbs(struct blogic_adapter *adapter)
 			/*
 			   Place CCB back on the Host Adapter's free list.
 			 */
-			blogic_dealloc_ccb(ccb);
+			blogic_dealloc_ccb(ccb, 1);
 			/*
 			   Call the SCSI Command Completion Routine.
 			 */
@@ -3034,6 +3036,7 @@ static int blogic_qcmd_lck(struct scsi_cmnd *command,
 	int buflen = scsi_bufflen(command);
 	int count;
 	struct blogic_ccb *ccb;
+	dma_addr_t sense_buf;
 
 	/*
 	   SCSI REQUEST_SENSE commands will be executed automatically by the
@@ -3179,10 +3182,17 @@ static int blogic_qcmd_lck(struct scsi_cmnd *command,
 	}
 	memcpy(ccb->cdb, cdb, cdblen);
 	ccb->sense_datalen = SCSI_SENSE_BUFFERSIZE;
-	ccb->sensedata = pci_map_single(adapter->pci_device,
+	ccb->command = command;
+	sense_buf = pci_map_single(adapter->pci_device,
 				command->sense_buffer, ccb->sense_datalen,
 				PCI_DMA_FROMDEVICE);
-	ccb->command = command;
+	if (dma_mapping_error(&adapter->pci_device->dev, sense_buf)) {
+		blogic_err("DMA mapping for sense data buffer failed\n",
+				adapter);
+		blogic_dealloc_ccb(ccb, 0);
+		return SCSI_MLQUEUE_HOST_BUSY;
+	}
+	ccb->sensedata = sense_buf;
 	command->scsi_done = comp_cb;
 	if (blogic_multimaster_type(adapter)) {
 		/*
@@ -3203,7 +3213,7 @@ static int blogic_qcmd_lck(struct scsi_cmnd *command,
 			if (!blogic_write_outbox(adapter, BLOGIC_MBOX_START,
 						ccb)) {
 				blogic_warn("Still unable to write Outgoing Mailbox - " "Host Adapter Dead?\n", adapter);
-				blogic_dealloc_ccb(ccb);
+				blogic_dealloc_ccb(ccb, 1);
 				command->result = DID_ERROR << 16;
 				command->scsi_done(command);
 			}
@@ -3337,7 +3347,7 @@ static int blogic_resetadapter(struct blogic_adapter *adapter, bool hard_reset)
 
 	for (ccb = adapter->all_ccbs; ccb != NULL; ccb = ccb->next_all)
 		if (ccb->status == BLOGIC_CCB_ACTIVE)
-			blogic_dealloc_ccb(ccb);
+			blogic_dealloc_ccb(ccb, 1);
 	/*
 	 * Wait a few seconds between the Host Adapter Hard Reset which
 	 * initiates a SCSI Bus Reset and issuing any SCSI Commands.  Some