The current approach to stop SCSI I/O during device removal is to clear sdev->request_queue->queuedata and to let scsi_request_fn() kill all outstanding requests once invoked with queuedata == NULL. This approach is racy since the prep_fn in certain SCSI drivers (e.g. sd) needs that queuedata pointer. Hence don't modify the queuedata pointer before invoking scsi_remove_device() but test for the QUEUE_FLAG_DEAD in scsi_request_fn() instead. See also http://www.spinics.net/lists/linux-scsi/msg56254.html. Reported-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> Cc: stabel@xxxxxxxxxxxxxxx --- drivers/scsi/hosts.c | 6 ++++++ drivers/scsi/scsi_lib.c | 13 +++---------- drivers/scsi/scsi_sysfs.c | 3 --- 3 files changed, 9 insertions(+), 13 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 351dc0b..5cf3a92 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -296,6 +296,12 @@ static void scsi_host_dev_release(struct device *dev) destroy_workqueue(shost->work_q); q = shost->uspace_req_q; if (q) { + /* + * Note: freeing queuedata before invoking scsi_free_queue() + * is safe here because no request function is associated with + * uspace_req_q. See also the __scsi_alloc_queue() call in + * drivers/scsi/scsi_tgt_lib.c. + */ kfree(q->queuedata); q->queuedata = NULL; scsi_free_queue(q); diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index b2c95db..c974032 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1486,7 +1486,9 @@ static void scsi_request_fn(struct request_queue *q) struct scsi_cmnd *cmd; struct request *req; - if (!sdev) { + BUG_ON(!sdev); + + if (unlikely(blk_queue_dead(q))) { while ((req = blk_peek_request(q)) != NULL) scsi_kill_request(req, q); return; @@ -1695,15 +1697,6 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) void scsi_free_queue(struct request_queue *q) { - unsigned long flags; - - WARN_ON(q->queuedata); - - /* cause scsi_request_fn() to kill all non-finished requests */ - spin_lock_irqsave(q->queue_lock, flags); - q->request_fn(q); - spin_unlock_irqrestore(q->queue_lock, flags); - blk_cleanup_queue(q); } diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 04c2a27..65801e9 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -971,9 +971,6 @@ void __scsi_remove_device(struct scsi_device *sdev) sdev->host->hostt->slave_destroy(sdev); transport_destroy_device(dev); - /* cause the request function to reject all I/O requests */ - sdev->request_queue->queuedata = NULL; - /* Freeing the queue signals to block that we're done */ scsi_free_queue(sdev->request_queue); put_device(dev); -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
