Two fixes for updating nr_hw_queues. The first patch fixes the following scenario: Kyber depends on the mapping between cpu and nr_hw_queues. When update nr_hw_queues, elevator_type->ops.mq.init_hctx will be invoked before the mapping is adapted correctly, this would cause panic in kyber. The second patch fixes the following scenario: part_in_flight/rw will invoke blk_mq_in_flight/rw to account the inflight requests. It will access the queue_hw_ctx and nr_hw_queues w/o any protection. When updating nr_hw_queues and blk_mq_in_flight /rw occur concurrently, panic comes up. Jianchao Wang (2) blk-mq: init hctx sched after update cpu & nr_hw_queues blk-mq: sync the update nr_hw_queues with part_in_flight block/blk-mq.c | 40 ++++++++++++++++++++++++++++++++-------- block/blk.h | 2 ++ block/elevator.c | 20 ++++++++++++-------- block/genhd.c | 10 ++++++++-- include/linux/blkdev.h | 4 ++++ 5 files changed, 58 insertions(+), 18 deletions(-) Thanks Jianchao
