scsi: Add intermediate STARGET_REMOVE state to scsi_target_state

Add intermediate STARGET_REMOVE state to scsi_target_state to avoid running into the BUG_ON() in scsi_target_reap(). The STARGET_REMOVE state is only valid in the path from scsi_remove_target() to scsi_target_destroy() indicating this target is going to be removed. This re-fixes the problem introduced in commits bc3f02a ("[SCSI] scsi_remove_target: fix softlockup regression on hot remove") and 4099819 ("scsi: restart list search after unlock in scsi_remove_target") in a more comprehensive way. [mkp: Included James' fix for scsi_target_destroy()] Signed-off-by: Johannes Thumshirn <[email protected]> Fixes: 4099819 Cc: [email protected] Reported-by: Sergey Senozhatsky <[email protected]> Tested-by: Sergey Senozhatsky <[email protected]> Reviewed-by: Ewan D. Milne <[email protected]> Reviewed-by: Hannes Reinecke <[email protected]> Reviewed-by: James Bottomley <[email protected]> Signed-off-by: Martin K. Petersen <[email protected]>
anholt · Apr 15, 2016 · f05795d · f05795d
1 parent be2a266
commit f05795d
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diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
@@ -319,6 +319,7 @@ static void scsi_target_destroy(struct scsi_target *starget)
 	struct Scsi_Host *shost = dev_to_shost(dev->parent);
 	unsigned long flags;
 
+	BUG_ON(starget->state == STARGET_DEL);
 	starget->state = STARGET_DEL;
 	transport_destroy_device(dev);
 	spin_lock_irqsave(shost->host_lock, flags);

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
@@ -1374,11 +1374,13 @@ void scsi_remove_target(struct device *dev)
 	spin_lock_irqsave(shost->host_lock, flags);
 	list_for_each_entry(starget, &shost->__targets, siblings) {
 		if (starget->state == STARGET_DEL ||
+		    starget->state == STARGET_REMOVE ||
 		    starget == last_target)
 			continue;
 		if (starget->dev.parent == dev || &starget->dev == dev) {
 			kref_get(&starget->reap_ref);
 			last_target = starget;
+			starget->state = STARGET_REMOVE;
 			spin_unlock_irqrestore(shost->host_lock, flags);
 			__scsi_remove_target(starget);
 			scsi_target_reap(starget);

diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
@@ -248,6 +248,7 @@ scmd_printk(const char *, const struct scsi_cmnd *, const char *, ...);
 enum scsi_target_state {
 	STARGET_CREATED = 1,
 	STARGET_RUNNING,
+	STARGET_REMOVE,
 	STARGET_DEL,
 };