From a72c374f97a4c7b2f9dde5144c867fec4bdcd798 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Wed, 9 Jun 2021 09:58:22 +0800 Subject: block: mark queue init done at the end of blk_register_queue Mark queue init done when everything is done well in blk_register_queue(), so that wbt_enable_default() can be run quickly without any RCU period involved since adding rq qos requires to freeze queue. Also no any side effect by delaying to mark queue init done. Reported-by: Yi Zhang Cc: Bart Van Assche Signed-off-by: Ming Lei Reviewed-by: Bart Van Assche Tested-by: Yi Zhang Link: https://lore.kernel.org/r/20210609015822.103433-3-ming.lei@redhat.com Signed-off-by: Jens Axboe --- block/blk-sysfs.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) (limited to 'block') diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index f89e2fc3963b..370d83c18057 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -866,20 +866,6 @@ int blk_register_queue(struct gendisk *disk) "%s is registering an already registered queue\n", kobject_name(&dev->kobj)); - /* - * SCSI probing may synchronously create and destroy a lot of - * request_queues for non-existent devices. Shutting down a fully - * functional queue takes measureable wallclock time as RCU grace - * periods are involved. To avoid excessive latency in these - * cases, a request_queue starts out in a degraded mode which is - * faster to shut down and is made fully functional here as - * request_queues for non-existent devices never get registered. - */ - if (!blk_queue_init_done(q)) { - blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q); - percpu_ref_switch_to_percpu(&q->q_usage_counter); - } - blk_queue_update_readahead(q); ret = blk_trace_init_sysfs(dev); @@ -938,6 +924,21 @@ int blk_register_queue(struct gendisk *disk) ret = 0; unlock: mutex_unlock(&q->sysfs_dir_lock); + + /* + * SCSI probing may synchronously create and destroy a lot of + * request_queues for non-existent devices. Shutting down a fully + * functional queue takes measureable wallclock time as RCU grace + * periods are involved. To avoid excessive latency in these + * cases, a request_queue starts out in a degraded mode which is + * faster to shut down and is made fully functional here as + * request_queues for non-existent devices never get registered. + */ + if (!blk_queue_init_done(q)) { + blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q); + percpu_ref_switch_to_percpu(&q->q_usage_counter); + } + return ret; } EXPORT_SYMBOL_GPL(blk_register_queue); -- cgit v1.2.3