[GIT PULL] SCSI fixes for 5.14-rc7

* [GIT PULL] SCSI fixes for 5.14-rc7
@ 2021-08-28 18:09 James Bottomley
  2021-08-28 18:46 ` pr-tracker-bot
  0 siblings, 1 reply; 2+ messages in thread
From: James Bottomley @ 2021-08-28 18:09 UTC (permalink / raw)
  To: Andrew Morton, Linus Torvalds; +Cc: linux-scsi, linux-kernel

A single fix for a race introduced by a fix that went up in 5.14-rc5.

The patch is available here:

git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git scsi-fixes

The short changelog is:

Li Jinlin (1):
      scsi: core: Fix hang of freezing queue between blocking and running device

And the diffstat:

 drivers/scsi/scsi_sysfs.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

With full diff below.

James

---

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index ae9bfc658203..c0d31119d6d7 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -808,12 +808,15 @@ store_state_field(struct device *dev, struct device_attribute *attr,
 	ret = scsi_device_set_state(sdev, state);
 	/*
 	 * If the device state changes to SDEV_RUNNING, we need to
-	 * rescan the device to revalidate it, and run the queue to
-	 * avoid I/O hang.
+	 * 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.
 	 */
 	if (ret == 0 && state == SDEV_RUNNING) {
-		scsi_rescan_device(dev);
 		blk_mq_run_hw_queues(sdev->request_queue, true);
+		scsi_rescan_device(dev);
 	}
 	mutex_unlock(&sdev->state_mutex);
 


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