At least in theory the mapped device can disappear after rq_completed() has invoked dm_put() and before the queue of the mapped device has been run. Avoid this by running the queue synchronously instead of asynchronously. Note: the previous patch makes invoking blk_run_queue() from inside dm_request_fn() safe.
Signed-off-by: Bart Van Assche <[email protected]> Cc: Alasdair G Kergon <[email protected]> Cc: Jens Axboe <[email protected]> Cc: Mike Snitzer <[email protected]> Cc: Tejun Heo <[email protected]> Cc: James Bottomley <[email protected]> Cc: Jun'ichi Nomura <[email protected]> --- drivers/md/dm.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 314a0e2..28b7ad4 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -728,14 +728,8 @@ static void rq_completed(struct mapped_device *md, int rw, int run_queue) if (!md_in_flight(md)) wake_up(&md->wait); - /* - * Run this off this callpath, as drivers could invoke end_io while - * inside their request_fn (and holding the queue lock). Calling - * back into ->request_fn() could deadlock attempting to grab the - * queue lock again. - */ if (run_queue) - blk_run_queue_async(md->queue); + blk_run_queue(md->queue); /* * dm_put() must be at the end of this function. See the comment above -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
