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 <bvanass...@acm.org>
Cc: James Bottomley <jbottom...@parallels.com>
Cc: Mike Christie <micha...@cs.wisc.edu>
Cc: Hannes Reinecke <h...@suse.de>
Cc: Tejun Heo <t...@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

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