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authorJianchao Wang <jianchao.w.wang@oracle.com>2018-08-21 15:15:03 +0800
committerJens Axboe <axboe@kernel.dk>2018-08-21 09:02:55 -0600
commitd48ece209f82c9ce07be942441b53d3fa3664936 (patch)
treeddf957d9d4edf1915558bc528fee6696cc02f1ed /block/blk.h
parentfcedba42d94ecdc14ca13d3797cba1ccbf743fa4 (diff)
downloadlinux-d48ece209f82c9ce07be942441b53d3fa3664936.tar.gz
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/blk.h')
-rw-r--r--block/blk.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/block/blk.h b/block/blk.h
index 644975e85053..9db4e389582c 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -234,6 +234,8 @@ static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq
 
 int elevator_init(struct request_queue *);
 int elevator_init_mq(struct request_queue *q);
+int elevator_switch_mq(struct request_queue *q,
+			      struct elevator_type *new_e);
 void elevator_exit(struct request_queue *, struct elevator_queue *);
 int elv_register_queue(struct request_queue *q);
 void elv_unregister_queue(struct request_queue *q);