[SCSI] Stop accepting SCSI requests before removing a device
Avoid that the code for requeueing SCSI requests triggers a
crash by making sure that that code isn't scheduled anymore
after a device has been removed.
Also, source code inspection of __scsi_remove_device() revealed
a race condition in this function: no new SCSI requests must be
accepted for a SCSI device after device removal started.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 8af6a64..b583277 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -155,13 +155,14 @@
/*
* Requeue this command. It will go before all other commands
- * that are already in the queue.
+ * that are already in the queue. Schedule requeue work under
+ * lock such that the kblockd_schedule_work() call happens
+ * before blk_cleanup_queue() finishes.
*/
spin_lock_irqsave(q->queue_lock, flags);
blk_requeue_request(q, cmd->request);
- spin_unlock_irqrestore(q->queue_lock, flags);
-
kblockd_schedule_work(q, &device->requeue_work);
+ spin_unlock_irqrestore(q->queue_lock, flags);
}
/*
