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| author | Jianchao Wang <jianchao.w.wang@oracle.com> | 2018-08-21 15:15:03 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-08-21 09:02:55 -0600 |
| commit | d48ece209f82c9ce07be942441b53d3fa3664936 (patch) | |
| tree | ddf957d9d4edf1915558bc528fee6696cc02f1ed /block/elevator.c | |
| parent | fcedba42d94ecdc14ca13d3797cba1ccbf743fa4 (diff) | |
| download | lwn-d48ece209f82c9ce07be942441b53d3fa3664936.tar.gz lwn-d48ece209f82c9ce07be942441b53d3fa3664936.zip | |
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 <jianchao.w.wang@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/elevator.c')
| -rw-r--r-- | block/elevator.c | 20 |
1 files changed, 12 insertions, 8 deletions
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. |