From: Jianchao Wang <jianchao.w.wang@oracle.com>
To: axboe@kernel.dk
Cc: tom.leiming@gmail.com, bart.vanassche@wdc.com,
keith.busch@linux.intel.com, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH V3 0/2] fixes for the updating nr_hw_queues
Date: Mon, 20 Aug 2018 15:20:04 +0800 [thread overview]
Message-ID: <1534749606-7311-1-git-send-email-jianchao.w.wang@oracle.com> (raw)
Hi Jens
Two fixes for updating nr_hw_queues.
The first patch fixes the following scenario:
io scheduler (kyber) depends on the mapping between ctx and hctx.
When update nr_hw_queues, io scheduler's 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.
V3:
- move the rcu and q_usage_counter checking into blk_mq_queue_tag_busy_iter
as suggestion of Ming.
- Add more comment about the __module_get in 1st patch.
- Add Ming's Reviewd-by on 1st patch.
V2:
- remove blk_mq_sched_init/exit_hctx in patch 1.
- use q_usage_counter instead of adding new member suggested by
Ming in patch 2.
- comment modification.
Jianchao Wang(2)
blk-mq: init hctx sched after update ctx and hctx
blk-mq: sync the update nr_hw_queues with
block/blk-mq-sched.c | 44 --------------------------------------------
block/blk-mq-sched.h | 5 -----
block/blk-mq-tag.c | 14 +++++++++++++-
block/blk-mq.c | 43 +++++++++++++++++++++++++++++++++++--------
block/blk.h | 2 ++
block/elevator.c | 20 ++++++++++++--------
include/linux/blkdev.h | 3 +++
7 files changed, 65 insertions(+), 66 deletions(-)
Thanks
Jianchao
next reply other threads:[~2018-08-20 7:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-20 7:20 Jianchao Wang [this message]
2018-08-20 7:20 ` [PATCH V3 1/2] blk-mq: init hctx sched after update ctx and hctx mapping Jianchao Wang
2018-08-20 14:45 ` Jens Axboe
2018-08-21 7:18 ` jianchao.wang
2018-08-20 7:20 ` [PATCH V3 2/2] blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter Jianchao Wang
2018-08-20 8:16 ` Ming Lei
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