From c100ec49fdd2222836ff8a17c7bfcc7611d2ee2b Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Mon, 8 Jan 2018 20:03:04 -0500 Subject: dm: fix incomplete request_queue initialization DM is no longer prone to having its request_queue be improperly initialized. Summary of changes: - defer DM's blk_register_queue() from add_disk()-time until dm_setup_md_queue() by using add_disk_no_queue_reg() in alloc_dev(). - dm_setup_md_queue() is updated to fully initialize DM's request_queue (_after_ all table loads have occurred and the request_queue's type, features and limits are known). A very welcome side-effect of these changes is DM no longer needs to: 1) backfill the "mq" sysfs entry (because historically DM didn't initialize the request_queue to use blk-mq until _after_ blk_register_queue() was called via add_disk()). 2) call elv_register_queue() to get .request_fn request-based DM device's "iosched" exposed in syfs. In addition, blk-mq debugfs support is now made available because request-based DM's blk-mq request_queue is now properly initialized before dm_setup_md_queue() calls blk_register_queue(). These changes also stave off the need to introduce new DM-specific workarounds in block core, e.g. this proposal: https://patchwork.kernel.org/patch/10067961/ In the end DM devices should be less unicorn in nature (relative to initialization and availability of block core infrastructure provided by the request_queue). Signed-off-by: Mike Snitzer Tested-by: Ming Lei Signed-off-by: Jens Axboe --- drivers/md/dm-rq.c | 9 --------- 1 file changed, 9 deletions(-) (limited to 'drivers/md/dm-rq.c') diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index 9d32f25489c2..c28357f5cb0e 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -713,8 +713,6 @@ int dm_old_init_request_queue(struct mapped_device *md, struct dm_table *t) return error; } - elv_register_queue(md->queue); - return 0; } @@ -812,15 +810,8 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t) } dm_init_md_queue(md); - /* backfill 'mq' sysfs registration normally done in blk_register_queue */ - err = blk_mq_register_dev(disk_to_dev(md->disk), q); - if (err) - goto out_cleanup_queue; - return 0; -out_cleanup_queue: - blk_cleanup_queue(q); out_tag_set: blk_mq_free_tag_set(md->tag_set); out_kfree_tag_set: -- cgit v1.2.3-59-g8ed1b