From: Christoph Hellwig <hch@lst.de>
To: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>,
James Bottomley <James.Bottomley@HansenPartnership.com>,
Jens Axboe <axboe@kernel.dk>,
Bart Van Assche <bvanassche@fusionio.com>,
Robert Elliott <Elliott@hp.com>,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 10/14] scsi: only maintain target_blocked if the driver has a target queue limit
Date: Wed, 9 Jul 2014 17:05:48 +0200 [thread overview]
Message-ID: <20140709150548.GB25257@lst.de> (raw)
In-Reply-To: <53BD254D.4000806@suse.de>
On Wed, Jul 09, 2014 at 01:19:41PM +0200, Hannes Reinecke wrote:
>> host_not_ready:
>> - atomic_dec(&scsi_target(sdev)->target_busy);
>> + if (scsi_target(sdev)->can_queue > 0)
>> + atomic_dec(&scsi_target(sdev)->target_busy);
>> not_ready:
>> /*
>> * lock q, handle tag, requeue req, and decrement device_busy. We
>>
> Hmm. 'can_queue' can be changed by the LLDD. Don't we need some sort of
> synchronization here?
While a few drivers change the host can_queue value at runtime none
do for the target. While I don't think driver should even change the
host one even modification to the target one is perfectly fine as long
as no driver drops it to zero.
next prev parent reply other threads:[~2014-07-09 15:05 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-25 16:51 scsi-mq V2 Christoph Hellwig
2014-06-25 16:51 ` [PATCH 01/14] sd: don't use rq->cmd_len before setting it up Christoph Hellwig
2014-07-09 11:12 ` Hannes Reinecke
2014-07-09 15:03 ` Christoph Hellwig
2014-06-25 16:51 ` [PATCH 02/14] scsi: split __scsi_queue_insert Christoph Hellwig
2014-07-09 11:12 ` Hannes Reinecke
2014-06-25 16:51 ` [PATCH 03/14] scsi: centralize command re-queueing in scsi_dispatch_fn Christoph Hellwig
2014-07-08 20:51 ` Elliott, Robert (Server Storage)
2014-07-09 6:40 ` Christoph Hellwig
2014-07-09 11:13 ` Hannes Reinecke
2014-06-25 16:51 ` [PATCH 04/14] scsi: set ->scsi_done before calling scsi_dispatch_cmd Christoph Hellwig
2014-07-09 11:14 ` Hannes Reinecke
2014-06-25 16:51 ` [PATCH 05/14] scsi: push host_lock down into scsi_{host,target}_queue_ready Christoph Hellwig
2014-07-09 11:14 ` Hannes Reinecke
2014-06-25 16:51 ` [PATCH 06/14] scsi: convert target_busy to an atomic_t Christoph Hellwig
2014-07-09 11:15 ` Hannes Reinecke
2014-06-25 16:51 ` [PATCH 07/14] scsi: convert host_busy to atomic_t Christoph Hellwig
2014-07-09 11:15 ` Hannes Reinecke
2014-06-25 16:51 ` [PATCH 08/14] scsi: convert device_busy " Christoph Hellwig
2014-07-09 11:16 ` Hannes Reinecke
2014-07-09 16:49 ` James Bottomley
2014-07-10 6:01 ` Christoph Hellwig
2014-06-25 16:51 ` [PATCH 09/14] scsi: fix the {host,target,device}_blocked counter mess Christoph Hellwig
2014-07-09 11:12 ` Hannes Reinecke
2014-07-10 6:06 ` Christoph Hellwig
2014-06-25 16:51 ` [PATCH 10/14] scsi: only maintain target_blocked if the driver has a target queue limit Christoph Hellwig
2014-07-09 11:19 ` Hannes Reinecke
2014-07-09 15:05 ` Christoph Hellwig [this message]
2014-06-25 16:51 ` [PATCH 11/14] scsi: unwind blk_end_request_all and blk_end_request_err calls Christoph Hellwig
2014-07-09 11:20 ` Hannes Reinecke
2014-06-25 16:51 ` [PATCH 12/14] scatterlist: allow chaining to preallocated chunks Christoph Hellwig
2014-07-09 11:21 ` Hannes Reinecke
2014-06-25 16:52 ` [PATCH 13/14] scsi: add support for a blk-mq based I/O path Christoph Hellwig
2014-07-09 11:25 ` Hannes Reinecke
2014-07-16 11:13 ` Mike Christie
2014-07-16 11:16 ` Christoph Hellwig
2014-06-25 16:52 ` [PATCH 14/14] fnic: reject device resets without assigned tags for the blk-mq case Christoph Hellwig
2014-07-09 11:27 ` Hannes Reinecke
2014-06-26 4:50 ` scsi-mq V2 Jens Axboe
2014-06-26 22:07 ` Elliott, Robert (Server Storage)
2014-06-27 14:42 ` Bart Van Assche
2014-06-30 15:20 ` Jens Axboe
2014-06-30 15:25 ` Christoph Hellwig
2014-06-30 15:54 ` Martin K. Petersen
2014-07-08 14:48 ` Christoph Hellwig
2014-07-09 16:39 ` Douglas Gilbert
2014-07-09 19:38 ` Jens Axboe
2014-07-10 0:53 ` Elliott, Robert (Server Storage)
2014-07-10 6:20 ` Christoph Hellwig
2014-07-10 13:36 ` Benjamin LaHaise
2014-07-10 13:39 ` Jens Axboe
2014-07-10 13:44 ` Benjamin LaHaise
2014-07-10 13:48 ` Jens Axboe
2014-07-10 13:50 ` Benjamin LaHaise
2014-07-10 13:52 ` Jens Axboe
2014-07-10 13:50 ` Christoph Hellwig
2014-07-10 13:52 ` Jens Axboe
2014-07-10 14:36 ` Elliott, Robert (Server Storage)
2014-07-10 14:45 ` Benjamin LaHaise
2014-07-10 15:11 ` Jeff Moyer
2014-07-10 19:59 ` Jens Axboe
2014-07-10 20:05 ` Jeff Moyer
2014-07-10 20:06 ` Jens Axboe
2014-07-10 15:51 ` Elliott, Robert (Server Storage)
2014-07-10 16:04 ` Christoph Hellwig
2014-07-10 16:14 ` Christoph Hellwig
2014-07-10 18:49 ` Elliott, Robert (Server Storage)
2014-07-10 19:14 ` Jeff Moyer
2014-07-10 19:36 ` Jeff Moyer
2014-07-10 21:10 ` Elliott, Robert (Server Storage)
2014-07-11 6:02 ` Elliott, Robert (Server Storage)
2014-07-11 6:14 ` Christoph Hellwig
2014-07-11 14:33 ` Elliott, Robert (Server Storage)
2014-07-11 14:55 ` Benjamin LaHaise
2014-07-12 21:50 ` Elliott, Robert (Server Storage)
2014-07-12 23:20 ` Elliott, Robert (Server Storage)
2014-07-13 17:15 ` Elliott, Robert (Server Storage)
2014-07-14 17:15 ` Benjamin LaHaise
2014-07-14 9:13 ` Sagi Grimberg
2014-08-21 12:32 ` Performance degradation in IO writes vs. reads (was scsi-mq V2) Sagi Grimberg
2014-08-21 13:03 ` Christoph Hellwig
2014-08-21 14:02 ` Sagi Grimberg
2014-08-24 16:41 ` Sagi Grimberg
-- strict thread matches above, loose matches on Subject: below --
2014-07-18 10:12 scsi-mq V4 Christoph Hellwig
2014-07-18 10:13 ` [PATCH 10/14] scsi: only maintain target_blocked if the driver has a target queue limit Christoph Hellwig
2014-07-25 19:10 ` Martin K. Petersen
2014-06-12 13:48 scsi-mq Christoph Hellwig
2014-06-12 13:49 ` [PATCH 10/14] scsi: only maintain target_blocked if the driver has a target queue limit Christoph Hellwig
2014-06-21 22:10 ` Elliott, Robert (Server Storage)
2014-06-23 7:09 ` Christoph Hellwig
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