From: Chris Leech <leech@pobox.com>
To: Sagi Grimberg <sagig@dev.mellanox.co.il>
Cc: mchristi@redhat.com,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
Guilherme Piccoli <gpiccoli@linux.vnet.ibm.com>,
Or Gerlitz <ogerlitz@mellanox.com>,
shlomopongratz@gmail.com
Subject: Re: [PATCH 1/1] iscsi: fix regression caused by session lock patch
Date: Thu, 12 Nov 2015 13:33:30 -0800 [thread overview]
Message-ID: <CAHNqLyWjuTkZEGAfoAkOZxeYYnuwbC9xctEdi5TGttXVC5NVDA@mail.gmail.com> (raw)
In-Reply-To: <56447FF7.40600@dev.mellanox.co.il>
On Thu, Nov 12, 2015 at 4:03 AM, Sagi Grimberg <sagig@dev.mellanox.co.il> wrote:
>
>> The bug is caused by this patch:
>>
>> 659743b02c411075b26601725947b21df0bb29c8
>>
>> which allowed the task lists to be manipulated under different locks
>> in the xmit and completion path.
>>
>> To fix the oops this patch just reverts that patch. It also reverts
>> these 2 patches for regressions that were also a result of that patch:
>
>
> Whoa now Mike, this is a major change. Can we take a step back and think
> about this for a second?
>
> My understanding is that the kfifo circular buffer design allows a
> writer (e.g. the producer) and a reader (e.g. the consumer) to avoid
> extra locking when accessing the kfifo buffer.
I don't think the problem is with the kfifo cmdpool, but rather the
connection mgmtqueue/cmdqueue linked lists. iscsi_task structs are linked
in using the task->running list_head.
- Chris
next prev parent reply other threads:[~2015-11-12 21:33 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-12 5:05 [PATCH 1/1] iscsi: fix regression caused by session lock patch mchristi
2015-11-12 12:03 ` Sagi Grimberg
2015-11-12 20:58 ` Mike Christie
2015-11-13 15:06 ` Or Gerlitz
2015-11-13 16:51 ` Mike Christie
2015-11-15 10:10 ` Or Gerlitz
[not found] ` <CAJ3xEMhQiywXo0=kRO7f=fW--1kc6mbNs_X7wLoYtXmRWeqBkg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-11-16 17:30 ` Michael Christie
2015-11-17 16:55 ` Or Gerlitz
2015-11-18 11:30 ` Or Gerlitz
[not found] ` <CAJ3xEMiu4XBO2d1oLnrgay1uLQmY871n9Kn-yp73PAkfKNnp9A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-11-18 18:39 ` Mike Christie
2016-11-07 18:15 ` Chris Leech
[not found] ` <20161107181556.cnhwst4nu63xtrqk-r8IHplWLGbA5tHQWs+pTeqPFFGjUI2lm2LY78lusg7I@public.gmane.org>
2016-11-07 18:23 ` Guilherme G. Piccoli
[not found] ` <5820C68E.6050206-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2016-11-09 5:21 ` Chris Leech
[not found] ` <20161109052142.j4psips7yvx7uohx-r8IHplWLGbA5tHQWs+pTeqPFFGjUI2lm2LY78lusg7I@public.gmane.org>
2016-11-12 1:51 ` Guilherme G. Piccoli
2017-02-06 13:19 ` Guilherme G. Piccoli
[not found] ` <631008bd-1e05-2c88-b153-695c76128eb4-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2017-02-06 17:27 ` Chris Leech
[not found] ` <1976057129.23970152.1486402069647.JavaMail.zimbra-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-02-06 18:24 ` Guilherme G. Piccoli
2017-02-06 19:22 ` Sagi Grimberg
2015-11-12 21:33 ` Chris Leech [this message]
2016-01-22 16:50 ` Brian King
2016-01-22 19:11 ` Mike Christie
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