diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index a663dbcbdd19cdfee2ac4cb7c2c0083dc750c938..711724a41fc74ef5da70227180c4c24d51f5f837 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -959,13 +959,11 @@ int blk_register_queue(struct gendisk *disk) blk_mq_debugfs_register(q); } - /* - * The flag of QUEUE_FLAG_REGISTERED isn't set yet, so elevator - * switch won't happen at all. - */ + mutex_lock(&q->sysfs_lock); if (q->request_fn || (q->mq_ops && q->elevator)) { ret = elv_register_queue(q, false); if (ret) { + mutex_unlock(&q->sysfs_lock); mutex_unlock(&q->sysfs_dir_lock); kobject_del(&q->kobj); blk_trace_remove_sysfs(dev); @@ -975,7 +973,6 @@ int blk_register_queue(struct gendisk *disk) has_elevator = true; } - mutex_lock(&q->sysfs_lock); blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q); wbt_enable_default(q); blk_throtl_register_queue(q); @@ -1049,12 +1046,10 @@ void blk_unregister_queue(struct gendisk *disk) blk_trace_remove_sysfs(disk_to_dev(disk)); - /* - * q->kobj has been removed, so it is safe to check if elevator - * exists without holding q->sysfs_lock. - */ + mutex_lock(&q->sysfs_lock); if (q->request_fn || (q->mq_ops && q->elevator)) elv_unregister_queue(q); + mutex_unlock(&q->sysfs_lock); mutex_unlock(&q->sysfs_dir_lock); /* Now that we've deleted all child objects, we can delete the queue. */ diff --git a/block/elevator.c b/block/elevator.c index a1e62af8bf338e9222d3ba05d600f4f1f260e1e0..77fde865bf7aa2261036fde8b0258be3eeb437d8 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -864,11 +864,9 @@ int elv_register_queue(struct request_queue *q, bool uevent) if (uevent) kobject_uevent(&e->kobj, KOBJ_ADD); - mutex_lock(&q->sysfs_lock); e->registered = 1; if (!e->uses_mq && e->type->ops.sq.elevator_registered_fn) e->type->ops.sq.elevator_registered_fn(q); - mutex_unlock(&q->sysfs_lock); } return error; } @@ -886,9 +884,7 @@ void elv_unregister_queue(struct request_queue *q) kobject_uevent(&e->kobj, KOBJ_REMOVE); kobject_del(&e->kobj); - mutex_lock(&q->sysfs_lock); e->registered = 0; - mutex_unlock(&q->sysfs_lock); } } @@ -959,32 +955,11 @@ int elevator_switch_mq(struct request_queue *q, lockdep_assert_held(&q->sysfs_lock); if (q->elevator) { - if (q->elevator->registered) { - mutex_unlock(&q->sysfs_lock); - - /* - * Concurrent elevator switch can't happen becasue - * sysfs write is always exclusively on same file. - * - * Also the elevator queue won't be freed after - * sysfs_lock is released becasue kobject_del() in - * blk_unregister_queue() waits for completion of - * .store & .show on its attributes. - */ + if (q->elevator->registered) elv_unregister_queue(q); - mutex_lock(&q->sysfs_lock); - } ioc_clear_queue(q); elevator_exit(q, q->elevator); - - /* - * sysfs_lock may be dropped, so re-check if queue is - * unregistered. If yes, don't switch to new elevator - * any more - */ - if (!test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags)) - return 0; } ret = blk_mq_init_sched(q, new_e); @@ -992,11 +967,7 @@ int elevator_switch_mq(struct request_queue *q, goto out; if (new_e) { - mutex_unlock(&q->sysfs_lock); - ret = elv_register_queue(q, true); - - mutex_lock(&q->sysfs_lock); if (ret) { elevator_exit(q, q->elevator); goto out;