From d48ece209f82c9ce07be942441b53d3fa3664936 Mon Sep 17 00:00:00 2001 From: Jianchao Wang Date: Tue, 21 Aug 2018 15:15:03 +0800 Subject: blk-mq: init hctx sched after update ctx and hctx mapping Currently, when update nr_hw_queues, IO scheduler's init_hctx will be invoked before the mapping between ctx and hctx is adapted correctly by blk_mq_map_swqueue. The IO scheduler init_hctx (kyber) may depend on this mapping and get wrong result and panic finally. A simply way to fix this is that switch the IO scheduler to 'none' before update the nr_hw_queues, and then switch it back after update nr_hw_queues. blk_mq_sched_init_/exit_hctx are removed due to nobody use them any more. Signed-off-by: Jianchao Wang Signed-off-by: Jens Axboe --- block/elevator.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) (limited to 'block/elevator.c') diff --git a/block/elevator.c b/block/elevator.c index fa828b5bfd4b..5ea6e7d600e4 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -933,16 +933,13 @@ void elv_unregister(struct elevator_type *e) } EXPORT_SYMBOL_GPL(elv_unregister); -static int elevator_switch_mq(struct request_queue *q, +int elevator_switch_mq(struct request_queue *q, struct elevator_type *new_e) { int ret; lockdep_assert_held(&q->sysfs_lock); - blk_mq_freeze_queue(q); - blk_mq_quiesce_queue(q); - if (q->elevator) { if (q->elevator->registered) elv_unregister_queue(q); @@ -968,8 +965,6 @@ static int elevator_switch_mq(struct request_queue *q, blk_add_trace_msg(q, "elv switch: none"); out: - blk_mq_unquiesce_queue(q); - blk_mq_unfreeze_queue(q); return ret; } @@ -1021,8 +1016,17 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) lockdep_assert_held(&q->sysfs_lock); - if (q->mq_ops) - return elevator_switch_mq(q, new_e); + if (q->mq_ops) { + blk_mq_freeze_queue(q); + blk_mq_quiesce_queue(q); + + err = elevator_switch_mq(q, new_e); + + blk_mq_unquiesce_queue(q); + blk_mq_unfreeze_queue(q); + + return err; + } /* * Turn on BYPASS and drain all requests w/ elevator private data. -- cgit v1.2.3