From: Keith Busch <keith.busch@linux.intel.com>
To: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Keith Busch <keith.busch@intel.com>,
linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>,
Jianchao Wang <jianchao.w.wang@oracle.com>,
linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCHv2 2/2] scsi: set timed out out mq requests to complete
Date: Tue, 24 Jul 2018 19:15:44 -0600 [thread overview]
Message-ID: <20180725011543.GA14596@localhost.localdomain> (raw)
In-Reply-To: <86e23e58-6f80-7957-30f7-8b0ce8cb50ce@wdc.com>
On Tue, Jul 24, 2018 at 03:46:17PM -0700, Bart Van Assche wrote:
> On 07/23/18 07:37, Keith Busch wrote:
> > + if (req->q->mq_ops && !blk_mq_mark_complete(req))
> > + return rtn;
> > if (scsi_abort_command(scmd) != SUCCESS) {
> > set_host_byte(scmd, DID_TIME_OUT);
> > scsi_eh_scmd_add(scmd);
>
> This change looks incomplete to me. I think the following scenario is not
> handled properly by the above patch:
> - host->hostt->eh_timed_out() gets called.
> - The request "req" completes from another context while
> host->hostt->eh_timed_out() is in progress.
> - host->hostt->eh_timed_out() calls scsi_finish_command().
>
> I think that scenario will lead to a double completion.
A bit of a moot point, isn't it? Not a single scsi lld directly calls
scsi_finish_command() from anywhere, much less through eh_timed_out().
WARNING: multiple messages have this Message-ID (diff)
From: keith.busch@linux.intel.com (Keith Busch)
Subject: [PATCHv2 2/2] scsi: set timed out out mq requests to complete
Date: Tue, 24 Jul 2018 19:15:44 -0600 [thread overview]
Message-ID: <20180725011543.GA14596@localhost.localdomain> (raw)
In-Reply-To: <86e23e58-6f80-7957-30f7-8b0ce8cb50ce@wdc.com>
On Tue, Jul 24, 2018@03:46:17PM -0700, Bart Van Assche wrote:
> On 07/23/18 07:37, Keith Busch wrote:
> > + if (req->q->mq_ops && !blk_mq_mark_complete(req))
> > + return rtn;
> > if (scsi_abort_command(scmd) != SUCCESS) {
> > set_host_byte(scmd, DID_TIME_OUT);
> > scsi_eh_scmd_add(scmd);
>
> This change looks incomplete to me. I think the following scenario is not
> handled properly by the above patch:
> - host->hostt->eh_timed_out() gets called.
> - The request "req" completes from another context while
> host->hostt->eh_timed_out() is in progress.
> - host->hostt->eh_timed_out() calls scsi_finish_command().
>
> I think that scenario will lead to a double completion.
A bit of a moot point, isn't it? Not a single scsi lld directly calls
scsi_finish_command() from anywhere, much less through eh_timed_out().
next prev parent reply other threads:[~2018-07-25 2:24 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-23 14:37 [PATCHv2 1/2] blk-mq: export setting request completion state Keith Busch
2018-07-23 14:37 ` Keith Busch
2018-07-23 14:37 ` [PATCHv2 2/2] scsi: set timed out out mq requests to complete Keith Busch
2018-07-23 14:37 ` Keith Busch
2018-07-24 7:56 ` Christoph Hellwig
2018-07-24 7:56 ` Christoph Hellwig
2018-07-24 22:46 ` Bart Van Assche
2018-07-24 22:46 ` Bart Van Assche
2018-07-25 1:15 ` Keith Busch [this message]
2018-07-25 1:15 ` Keith Busch
2018-07-25 1:56 ` Douglas Gilbert
2018-07-25 1:56 ` Douglas Gilbert
2018-07-25 2:48 ` Keith Busch
2018-07-25 2:48 ` Keith Busch
2018-07-25 15:52 ` Bart Van Assche
2018-07-25 15:52 ` Bart Van Assche
2018-07-25 16:48 ` Keith Busch
2018-07-25 16:48 ` Keith Busch
2018-07-24 7:56 ` [PATCHv2 1/2] blk-mq: export setting request completion state Christoph Hellwig
2018-07-24 7:56 ` Christoph Hellwig
2018-07-24 20:42 ` Jens Axboe
2018-07-24 20:42 ` Jens Axboe
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