diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index b874cb84bad9..2d46383e8d26 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1020,6 +1020,13 @@ static inline bool ubq_daemon_is_dying(struct ublk_queue *ubq) return ubq->ubq_daemon->flags & PF_EXITING; } +static void ublk_end_request(struct request *req, blk_status_t error) +{ + local_bh_disable(); + blk_mq_end_request(req, error); + local_bh_enable(); +} + /* todo: handle partial completion */ static inline void __ublk_complete_rq(struct request *req) { @@ -1027,6 +1034,7 @@ static inline void __ublk_complete_rq(struct request *req) struct ublk_io *io = &ubq->ios[req->tag]; unsigned int unmapped_bytes; blk_status_t res = BLK_STS_OK; + bool requeue; /* called from ublk_abort_queue() code path */ if (io->flags & UBLK_IO_FLAG_ABORTED) { @@ -1064,14 +1072,30 @@ static inline void __ublk_complete_rq(struct request *req) if (unlikely(unmapped_bytes < io->res)) io->res = unmapped_bytes; - if (blk_update_request(req, BLK_STS_OK, io->res)) + /* + * Run bio->bi_end_io() with softirqs disabled. If the final fput + * happens off this path, then that will prevent ublk's blkdev_release() + * from being called on current's task work, see fput() implementation. + * + * Otherwise, ublk server may not provide forward progress in case of + * reading the partition table from bdev_open() with disk->open_mutex + * held, and causes dead lock as we could already be holding + * disk->open_mutex here. + * + * Preferably we would not be doing IO with a mutex held that is also + * used for release, but this work-around will suffice for now. + */ + local_bh_disable(); + requeue = blk_update_request(req, BLK_STS_OK, io->res); + local_bh_enable(); + if (requeue) blk_mq_requeue_request(req, true); else __blk_mq_end_request(req, BLK_STS_OK); return; exit: - blk_mq_end_request(req, res); + ublk_end_request(req, res); } static void ublk_complete_rq(struct kref *ref) @@ -1149,7 +1173,7 @@ static inline void __ublk_abort_rq(struct ublk_queue *ubq, if (ublk_nosrv_dev_should_queue_io(ubq->dev)) blk_mq_requeue_request(rq, false); else - blk_mq_end_request(rq, BLK_STS_IOERR); + ublk_end_request(rq, BLK_STS_IOERR); } static inline void __ublk_rq_task_work(struct request *req,