1 files changed, 30 insertions, 7 deletions

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 6d7362e7367e..6faf1d6451b0 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -438,9 +438,12 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
 	struct list_head *this, *tmp;
 	struct scsi_vpd *vpd_pg80 = NULL, *vpd_pg83 = NULL;
 	unsigned long flags;
+	struct module *mod;
 
 	sdev = container_of(work, struct scsi_device, ew.work);
 
+	mod = sdev->host->hostt->module;
+
 	scsi_dh_release_device(sdev);
 
 	parent = sdev->sdev_gendev.parent;
@@ -481,11 +484,17 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
 
 	if (parent)
 		put_device(parent);
+	module_put(mod);
 }
 
 static void scsi_device_dev_release(struct device *dev)
 {
 	struct scsi_device *sdp = to_scsi_device(dev);
+
+	/* Set module pointer as NULL in case of module unloading */
+	if (!try_module_get(sdp->host->hostt->module))
+		sdp->host->hostt->module = NULL;
+
 	execute_in_process_context(scsi_device_dev_release_usercontext,
 				   &sdp->ew);
 }
@@ -767,6 +776,7 @@ store_state_field(struct device *dev, struct device_attribute *attr,
 	int i, ret;
 	struct scsi_device *sdev = to_scsi_device(dev);
 	enum scsi_device_state state = 0;
+	bool rescan_dev = false;
 
 	for (i = 0; i < ARRAY_SIZE(sdev_states); i++) {
 		const int len = strlen(sdev_states[i].name);
@@ -785,15 +795,28 @@ store_state_field(struct device *dev, struct device_attribute *attr,
 	}
 
 	mutex_lock(&sdev->state_mutex);
-	ret = scsi_device_set_state(sdev, state);
-	/*
-	 * If the device state changes to SDEV_RUNNING, we need to run
-	 * the queue to avoid I/O hang.
-	 */
-	if (ret == 0 && state == SDEV_RUNNING)
-		blk_mq_run_hw_queues(sdev->request_queue, true);
+	if (sdev->sdev_state == SDEV_RUNNING && state == SDEV_RUNNING) {
+		ret = 0;
+	} else {
+		ret = scsi_device_set_state(sdev, state);
+		if (ret == 0 && state == SDEV_RUNNING)
+			rescan_dev = true;
+	}
 	mutex_unlock(&sdev->state_mutex);
 
+	if (rescan_dev) {
+		/*
+		 * If the device state changes to SDEV_RUNNING, we need to
+		 * run the queue to avoid I/O hang, and rescan the device
+		 * to revalidate it. Running the queue first is necessary
+		 * because another thread may be waiting inside
+		 * blk_mq_freeze_queue_wait() and because that call may be
+		 * waiting for pending I/O to finish.
+		 */
+		blk_mq_run_hw_queues(sdev->request_queue, true);
+		scsi_rescan_device(dev);
+	}
+
 	return ret == 0 ? count : -EINVAL;
 }