qla2xxx: Fix request queue corruption.

When FW notify driver or driver detects low FW resource,
driver tries to send out Busy SCSI Status to tell Initiator
side to back off. During the send process, the lock was not held.

Cc: <stable@vger.kernel.org>
Signed-off-by: Quinn Tran <quinn.tran@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/scsi/qla2xxx/qla_target.c

@@ -5079,16 +5079,22 @@ qlt_send_busy(struct scsi_qla_host *vha,
 
 static int
 qlt_chk_qfull_thresh_hold(struct scsi_qla_host *vha,
-	struct atio_from_isp *atio)
+	struct atio_from_isp *atio, bool ha_locked)
 {
 	struct qla_hw_data *ha = vha->hw;
 	uint16_t status;
+	unsigned long flags;
 
 	if (ha->tgt.num_pend_cmds < Q_FULL_THRESH_HOLD(ha))
 		return 0;
 
+	if (!ha_locked)
+		spin_lock_irqsave(&ha->hardware_lock, flags);
 	status = temp_sam_status;
 	qlt_send_busy(vha, atio, status);
+	if (!ha_locked)
+		spin_unlock_irqrestore(&ha->hardware_lock, flags);
+
 	return 1;
 }
 
@@ -5133,7 +5139,7 @@ static void qlt_24xx_atio_pkt(struct scsi_qla_host *vha,
 
 
 		if (likely(atio->u.isp24.fcp_cmnd.task_mgmt_flags == 0)) {
-			rc = qlt_chk_qfull_thresh_hold(vha, atio);
+			rc = qlt_chk_qfull_thresh_hold(vha, atio, ha_locked);
 			if (rc != 0) {
 				tgt->atio_irq_cmd_count--;
 				return;
@@ -5256,7 +5262,7 @@ static void qlt_response_pkt(struct scsi_qla_host *vha, response_t *pkt)
 			break;
 		}
 
-		rc = qlt_chk_qfull_thresh_hold(vha, atio);
+		rc = qlt_chk_qfull_thresh_hold(vha, atio, true);
 		if (rc != 0) {
 			tgt->irq_cmd_count--;
 			return;