[PATCH V5 0/4] blk-mq: implement queue quiesce via percpu_ref for BLK_MQ_F_BLOCKING

[Keith Busch]

On Fri, Sep 11, 2020 at 10:41:13AM +0800, Ming Lei wrote:
> Hi Jens,
> 
> The 1st patch add .mq_quiesce_mutex for serializing quiesce/unquiesce,
> and prepares for replacing srcu with percpu_ref.
> 
> The 2nd patch replaces srcu with percpu_ref.
> 
> The 3rd patch adds tagset quiesce interface.
> 
> The 4th patch applies tagset quiesce interface for NVMe subsystem.
> 
> V5:
> 	- warn once in case that driver unquiesces its queue being
> 	  quiesce and not done, only patch 2 is modified
> 
> V4:
> 	- remove .mq_quiesce_mutex, and switch to test_and_[set|clear] for
> 	avoiding duplicated quiesce action
> 	- pass blktests(block, nvme)
> 
> V3:
> 	- add tagset quiesce interface
> 	- apply tagset quiesce interface for NVMe
> 	- pass blktests(block, nvme)
> 
> V2:
> 	- add .mq_quiesce_lock
> 	- add comment on patch 2 wrt. handling hctx_lock() failure
> 	- trivial patch style change
> 
> Ming Lei (3):
>   block: use test_and_{clear|test}_bit to set/clear QUEUE_FLAG_QUIESCED
>   blk-mq: implement queue quiesce via percpu_ref for BLK_MQ_F_BLOCKING
>   blk-mq: add tagset quiesce interface
> 
> Sagi Grimberg (1):
>   nvme: use blk_mq_[un]quiesce_tagset
> 
>  block/blk-core.c         |  13 +++
>  block/blk-mq-sysfs.c     |   2 -
>  block/blk-mq.c           | 182 +++++++++++++++++++++++++--------------
>  block/blk-sysfs.c        |   6 +-
>  block/blk.h              |   2 +
>  drivers/nvme/host/core.c |  19 ++--
>  include/linux/blk-mq.h   |  10 +--
>  include/linux/blkdev.h   |   4 +
>  8 files changed, 154 insertions(+), 84 deletions(-)
> 
> Cc: Hannes Reinecke <hare at suse.de>
> Cc: Sagi Grimberg <sagi at grimberg.me>
> Cc: Bart Van Assche <bvanassche at acm.org>
> Cc: Johannes Thumshirn <Johannes.Thumshirn at wdc.com>
> Cc: Chao Leng <lengchao at huawei.com>
> -- 

This looks good to me.

Reviewed-by: Keith Busch <kbusch at kernel.org>