Patch "IB/srp: Fix race conditions related to task management" has been added to the 4.9-stable tree

@@ -1872,12 +1872,17 @@ static void srp_process_rsp(struct srp_r
 	if (unlikely(rsp->tag & SRP_TAG_TSK_MGMT)) {
 		spin_lock_irqsave(&ch->lock, flags);
 		ch->req_lim += be32_to_cpu(rsp->req_lim_delta);
+		if (rsp->tag == ch->tsk_mgmt_tag) {
+			ch->tsk_mgmt_status = -1;
+			if (be32_to_cpu(rsp->resp_data_len) >= 4)
+				ch->tsk_mgmt_status = rsp->data[3];
+			complete(&ch->tsk_mgmt_done);
+		} else {
+			shost_printk(KERN_ERR, target->scsi_host,
+				     "Received tsk mgmt response too late for tag %#llx\n",
+				     rsp->tag);
+		}
 		spin_unlock_irqrestore(&ch->lock, flags);
-
-		ch->tsk_mgmt_status = -1;
-		if (be32_to_cpu(rsp->resp_data_len) >= 4)
-			ch->tsk_mgmt_status = rsp->data[3];
-		complete(&ch->tsk_mgmt_done);
 	} else {
 		scmnd = scsi_host_find_tag(target->scsi_host, rsp->tag);
 		if (scmnd && scmnd->host_scribble) {

@@ -2516,19 +2521,18 @@ srp_change_queue_depth(struct scsi_devic
 }
 
 static int srp_send_tsk_mgmt(struct srp_rdma_ch *ch, u64 req_tag, u64 lun,
-			     u8 func)
+			     u8 func, u8 *status)
 {
 	struct srp_target_port *target = ch->target;
 	struct srp_rport *rport = target->rport;
 	struct ib_device *dev = target->srp_host->srp_dev->dev;
 	struct srp_iu *iu;
 	struct srp_tsk_mgmt *tsk_mgmt;
+	int res;
 
 	if (!ch->connected || target->qp_in_error)
 		return -1;
 
-	init_completion(&ch->tsk_mgmt_done);
-
 	/*
 	 * Lock the rport mutex to avoid that srp_create_ch_ib() is
 	 * invoked while a task management function is being sent.

@@ -2551,10 +2555,16 @@ static int srp_send_tsk_mgmt(struct srp_
 
 	tsk_mgmt->opcode 	= SRP_TSK_MGMT;
 	int_to_scsilun(lun, &tsk_mgmt->lun);
-	tsk_mgmt->tag		= req_tag | SRP_TAG_TSK_MGMT;
 	tsk_mgmt->tsk_mgmt_func = func;
 	tsk_mgmt->task_tag	= req_tag;
 
+	spin_lock_irq(&ch->lock);
+	ch->tsk_mgmt_tag = (ch->tsk_mgmt_tag + 1) | SRP_TAG_TSK_MGMT;
+	tsk_mgmt->tag = ch->tsk_mgmt_tag;
+	spin_unlock_irq(&ch->lock);
+
+	init_completion(&ch->tsk_mgmt_done);
+
 	ib_dma_sync_single_for_device(dev, iu->dma, sizeof *tsk_mgmt,
 				      DMA_TO_DEVICE);
 	if (srp_post_send(ch, iu, sizeof(*tsk_mgmt))) {

@@ -2563,13 +2573,15 @@ static int srp_send_tsk_mgmt(struct srp_
 
 		return -1;
 	}
+	res = wait_for_completion_timeout(&ch->tsk_mgmt_done,
+					msecs_to_jiffies(SRP_ABORT_TIMEOUT_MS));
+	if (res > 0 && status)
+		*status = ch->tsk_mgmt_status;
 	mutex_unlock(&rport->mutex);
 
-	if (!wait_for_completion_timeout(&ch->tsk_mgmt_done,
-					 msecs_to_jiffies(SRP_ABORT_TIMEOUT_MS)))
-		return -1;
+	WARN_ON_ONCE(res < 0);
 
-	return 0;
+	return res > 0 ? 0 : -1;
 }
 
 static int srp_abort(struct scsi_cmnd *scmnd)

@@ -2595,7 +2607,7 @@ static int srp_abort(struct scsi_cmnd *s
 	shost_printk(KERN_ERR, target->scsi_host,
 		     "Sending SRP abort for tag %#x\n", tag);
 	if (srp_send_tsk_mgmt(ch, tag, scmnd->device->lun,
-			      SRP_TSK_ABORT_TASK) == 0)
+			      SRP_TSK_ABORT_TASK, NULL) == 0)
 		ret = SUCCESS;
 	else if (target->rport->state == SRP_RPORT_LOST)
 		ret = FAST_IO_FAIL;

@@ -2613,14 +2625,15 @@ static int srp_reset_device(struct scsi_
 	struct srp_target_port *target = host_to_target(scmnd->device->host);
 	struct srp_rdma_ch *ch;
 	int i;
+	u8 status;
 
 	shost_printk(KERN_ERR, target->scsi_host, "SRP reset_device called\n");
 
 	ch = &target->ch[0];
 	if (srp_send_tsk_mgmt(ch, SRP_TAG_NO_REQ, scmnd->device->lun,
-			      SRP_TSK_LUN_RESET))
+			      SRP_TSK_LUN_RESET, &status))
 		return FAILED;
-	if (ch->tsk_mgmt_status)
+	if (status)
 		return FAILED;
 
 	for (i = 0; i < target->ch_count; i++) {

@@ -163,6 +163,7 @@ struct srp_rdma_ch {
 	int			max_ti_iu_len;
 	int			comp_vector;
 
+	u64			tsk_mgmt_tag;
 	struct completion	tsk_mgmt_done;
 	u8			tsk_mgmt_status;
 	bool			connected;