[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_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 9aa578a..d19d7e9 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -967,13 +967,20 @@
device_del(dev);
} else
put_device(&sdev->sdev_dev);
+
+ /*
+ * Stop accepting new requests and wait until all queuecommand() and
+ * scsi_run_queue() invocations have finished before tearing down the
+ * device.
+ */
scsi_device_set_state(sdev, SDEV_DEL);
+ blk_cleanup_queue(sdev->request_queue);
+ cancel_work_sync(&sdev->requeue_work);
+
if (sdev->host->hostt->slave_destroy)
sdev->host->hostt->slave_destroy(sdev);
transport_destroy_device(dev);
- /* Freeing the queue signals to block that we're done */
- blk_cleanup_queue(sdev->request_queue);
put_device(dev);
}