diff options
| author | Bart Van Assche <bvanassche@acm.org> | 2012-06-29 15:36:07 +0000 |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2012-07-20 08:58:41 +0100 |
| commit | b485462aca7df4e32bcf7efb6f84a69e8b640243 (patch) | |
| tree | 744345ebe5c761a46a28a495fae82b6dd4d9e28b | |
| parent | 84feb1664e5e6823105414df77740fda70846b99 (diff) | |
[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>
| -rw-r--r-- | drivers/scsi/scsi_lib.c | 7 | ||||
| -rw-r--r-- | drivers/scsi/scsi_sysfs.c | 11 |
2 files changed, 13 insertions, 5 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 8af6a6497c4f..b58327758c58 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -155,13 +155,14 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) /* * 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); } /* diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 9aa578a5da11..d19d7e99626d 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -967,13 +967,20 @@ void __scsi_remove_device(struct scsi_device *sdev) 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); } |