[SCSI] qla4xxx: Fixed target discovery failed issue.

When sendtargets response is greater then max receive data segment length,
the passthrough IOCB failed with data overrun status. Solution is to
allocate space for iSCSI header in the IOCB response buffer.

JIRA Key: UPSISCSI-147

Signed-off-by: Manish Rangankar <manish.rangankar@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/qla4xxx/ql4_def.h

@@ -631,6 +631,7 @@ struct ql4_task_data {
 	dma_addr_t data_dma;
 	void *req_buffer;
 	dma_addr_t req_dma;
+	uint32_t req_len;
 	void *resp_buffer;
 	dma_addr_t resp_dma;
 	uint32_t resp_len;

drivers/scsi/qla4xxx/ql4_iocb.c

@@ -407,7 +407,7 @@ int qla4xxx_send_passthru0(struct iscsi_task *task)
 	passthru_iocb->timeout = cpu_to_le16(PT_DEFAULT_TIMEOUT);
 
 	/* Setup the out & in DSDs */
-	if (task->data_count) {
+	if (task_data->req_len) {
 		memcpy((uint8_t *)task_data->req_buffer +
 		       sizeof(struct iscsi_hdr), task->data, task->data_count);
 		ctrl_flags |= PT_FLAG_SEND_BUFFER;

drivers/scsi/qla4xxx/ql4_os.c

@@ -1272,7 +1272,7 @@ static int qla4xxx_alloc_pdu(struct iscsi_task *task, uint8_t opcode)
 	DEBUG2(ql4_printk(KERN_INFO, ha, "%s: MaxRecvLen %u, iscsi hrd %d\n",
 		      __func__, task->conn->max_recv_dlength, hdr_len));
 
-	task_data->resp_len = task->conn->max_recv_dlength;
+	task_data->resp_len = task->conn->max_recv_dlength + hdr_len;
 	task_data->resp_buffer = dma_alloc_coherent(&ha->pdev->dev,
 						    task_data->resp_len,
 						    &task_data->resp_dma,
@@ -1280,8 +1280,9 @@ static int qla4xxx_alloc_pdu(struct iscsi_task *task, uint8_t opcode)
 	if (!task_data->resp_buffer)
 		goto exit_alloc_pdu;
 
+	task_data->req_len = task->data_count + hdr_len;
 	task_data->req_buffer = dma_alloc_coherent(&ha->pdev->dev,
-						   task->data_count + hdr_len,
+						   task_data->req_len,
 						   &task_data->req_dma,
 						   GFP_ATOMIC);
 	if (!task_data->req_buffer)
@@ -1299,7 +1300,7 @@ exit_alloc_pdu:
 				  task_data->resp_buffer, task_data->resp_dma);
 
 	if (task_data->req_buffer)
-		dma_free_coherent(&ha->pdev->dev, task->data_count + hdr_len,
+		dma_free_coherent(&ha->pdev->dev, task_data->req_len,
 				  task_data->req_buffer, task_data->req_dma);
 	return -ENOMEM;
 }
@@ -1328,7 +1329,7 @@ static void qla4xxx_task_cleanup(struct iscsi_task *task)
 
 	dma_free_coherent(&ha->pdev->dev, task_data->resp_len,
 			  task_data->resp_buffer, task_data->resp_dma);
-	dma_free_coherent(&ha->pdev->dev, task->data_count + hdr_len,
+	dma_free_coherent(&ha->pdev->dev, task_data->req_len,
 			  task_data->req_buffer, task_data->req_dma);
 	return;
 }