[PATCH v10 3/9] Avoid calling __scsi_remove_device() twice

[Bart Van Assche <bvanassche@acm.org>]

SCSI devices are added to the shost->__devices list from inside
scsi_alloc_sdev(). If something goes wrong during LUN scanning,
e.g. a transport layer failure occurs, then __scsi_remove_device()
can get invoked by the LUN scanning code for a SCSI device in
state SDEV_CREATED_BLOCK or SDEV_BLOCKED. If this happens then
the SCSI device has not yet been added to sysfs (is_visible == 0).
Make sure that if this happens these devices are transitioned
into state SDEV_DEL. This avoids that __scsi_remove_device()
gets invoked a second time by scsi_forget_host().

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Tejun Heo <tj@kernel.org>
---
 drivers/scsi/scsi_lib.c   |    2 ++
 drivers/scsi/scsi_sysfs.c |    7 ++++---
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index d84cbd0..34cdcbc 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2176,6 +2176,8 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 		case SDEV_OFFLINE:
 		case SDEV_TRANSPORT_OFFLINE:
 		case SDEV_CANCEL:
+		case SDEV_BLOCK:
+		case SDEV_CREATED_BLOCK:
 			break;
 		default:
 			goto illegal;
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 34f1b39..f869ef85 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -956,8 +956,9 @@ void __scsi_remove_device(struct scsi_device *sdev)
 	unsigned long flags;
 
 	if (sdev->is_visible) {
-		if (scsi_device_set_state(sdev, SDEV_CANCEL) != 0)
-			return;
+		WARN(scsi_device_set_state(sdev, SDEV_CANCEL) != 0,
+		     "%s: unexpected state %d\n", dev_name(&sdev->sdev_gendev),
+		     sdev->sdev_state);
 
 		bsg_unregister_queue(sdev->request_queue);
 		device_unregister(&sdev->sdev_dev);
@@ -971,7 +972,7 @@ void __scsi_remove_device(struct scsi_device *sdev)
 	 * scsi_run_queue() invocations have finished before tearing down the
 	 * device.
 	 */
-	scsi_device_set_state(sdev, SDEV_DEL);
+	WARN_ON_ONCE(scsi_device_set_state(sdev, SDEV_DEL) != 0);
 	blk_cleanup_queue(sdev->request_queue);
 	cancel_work_sync(&sdev->requeue_work);
 
-- 
1.7.10.4