From: keith.busch@linux.intel.com (Keith Busch)
Subject: [RFC PATCH 3/3] blk-mq: Remove generation seqeunce
Date: Tue, 22 May 2018 09:01:19 -0600 [thread overview]
Message-ID: <20180522150119.GA8295@localhost.localdomain> (raw)
In-Reply-To: <CACVXFVNWK-r6FrsNOmmETZXf9MLPQUNR3Nmf_hmDgaOUivpbYQ@mail.gmail.com>
On Tue, May 22, 2018@10:57:40PM +0800, Ming Lei wrote:
> OK, that still depends on driver's behaviour, even though it is true
> for NVMe, you still have to audit other drivers about this sync
> because it is required by your patch.
Okay, forget about nvme for a moment here. Please run this thought
experiment to decide if what you're saying is even plausible for any
block driver with the existing implementation:
Your scenario has a driver return EH_HANDLED for a timed out request. The
timeout work then completes the request. The request may then be
reallocated for a new command and dispatched.
At approximately the same time, you're saying the driver that returned
EH_HANDLED may then call blk_mq_complete_request() in reference to the
*old* request that it returned EH_HANDLED for, incorrectly completing
the new request before it is done. That will inevitably lead to data
corruption. Is that happening today in any driver?
next prev parent reply other threads:[~2018-05-22 15:01 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-21 23:11 [RFC PATCH 0/3] blk-mq: Timeout rework Keith Busch
2018-05-21 23:11 ` [RFC PATCH 1/3] blk-mq: Reference count request usage Keith Busch
2018-05-22 2:27 ` Ming Lei
2018-05-22 15:19 ` Christoph Hellwig
2018-05-21 23:11 ` [RFC PATCH 2/3] blk-mq: Fix timeout and state order Keith Busch
2018-05-22 2:28 ` Ming Lei
2018-05-22 15:24 ` Christoph Hellwig
2018-05-22 16:27 ` Bart Van Assche
2018-05-21 23:11 ` [RFC PATCH 3/3] blk-mq: Remove generation seqeunce Keith Busch
2018-05-21 23:29 ` Bart Van Assche
2018-05-22 14:15 ` Keith Busch
2018-05-22 16:29 ` Bart Van Assche
2018-05-22 16:34 ` Keith Busch
2018-05-22 16:48 ` Bart Van Assche
2018-05-22 2:49 ` Ming Lei
2018-05-22 3:16 ` Jens Axboe
2018-05-22 3:47 ` Ming Lei
2018-05-22 3:51 ` Jens Axboe
2018-05-22 8:51 ` Ming Lei
2018-05-22 14:35 ` Jens Axboe
2018-05-22 14:20 ` Keith Busch
2018-05-22 14:37 ` Ming Lei
2018-05-22 14:46 ` Keith Busch
2018-05-22 14:57 ` Ming Lei
2018-05-22 15:01 ` Keith Busch [this message]
2018-05-22 15:07 ` Ming Lei
2018-05-22 15:17 ` Keith Busch
2018-05-22 15:23 ` Ming Lei
2018-05-22 16:17 ` Christoph Hellwig
2018-05-23 0:34 ` Ming Lei
2018-05-23 14:35 ` Keith Busch
2018-05-24 1:52 ` Ming Lei
2018-05-23 5:48 ` Hannes Reinecke
2018-07-12 18:16 ` Bart Van Assche
2018-07-12 19:24 ` Keith Busch
2018-07-12 22:24 ` Bart Van Assche
2018-07-13 1:12 ` jianchao.wang
2018-07-13 2:40 ` jianchao.wang
2018-07-13 15:43 ` Keith Busch
2018-07-13 15:52 ` Bart Van Assche
2018-07-13 18:47 ` Keith Busch
2018-07-13 23:03 ` Bart Van Assche
2018-07-13 23:58 ` Keith Busch
2018-07-18 19:56 ` hch
2018-07-18 20:39 ` hch
2018-07-18 21:05 ` Bart Van Assche
2018-07-18 22:53 ` Keith Busch
2018-07-18 20:53 ` Keith Busch
2018-07-18 20:58 ` Bart Van Assche
2018-07-18 21:17 ` Keith Busch
2018-07-18 21:30 ` Bart Van Assche
2018-07-18 21:33 ` Keith Busch
2018-07-19 13:19 ` hch
2018-07-19 14:59 ` Keith Busch
2018-07-19 15:56 ` Keith Busch
2018-07-19 16:04 ` Bart Van Assche
2018-07-19 16:22 ` Keith Busch
2018-07-19 16:29 ` hch
2018-07-19 20:18 ` Keith Busch
2018-07-19 13:22 ` hch
2018-05-21 23:29 ` [RFC PATCH 0/3] blk-mq: Timeout rework Bart Van Assche
2018-05-22 14:06 ` Keith Busch
2018-05-22 16:30 ` Bart Van Assche
2018-05-22 16:44 ` Keith Busch
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