From mboxrd@z Thu Jan  1 00:00:00 1970
From: mrybczyn@kalray.eu (Marta Rybczynska)
Date: Tue, 25 Jun 2019 17:45:02 +0200 (CEST)
Subject: [PATCH] nvmet-rdma: Suppress a lockdep complaint
In-Reply-To: <7d28ee3d-0326-6d31-1cc6-13acc48e0d4d@acm.org>
References: <20190403230402.119428-1-bvanassche@acm.org>
 <1554392625.118779.243.camel@acm.org>
 <1035014818.27150671.1561441925414.JavaMail.zimbra@kalray.eu>
 <7d28ee3d-0326-6d31-1cc6-13acc48e0d4d@acm.org>
Message-ID: <1492173308.27223699.1561477502288.JavaMail.zimbra@kalray.eu>

----- On 25 Jun, 2019,@17:18, Bart Van Assche bvanassche@acm.org wrote:

> On 6/24/19 10:52 PM, Marta Rybczynska wrote:
>> ----- On 4 Apr, 2019,@17:43, Bart Van Assche bvanassche@acm.org wrote:
>>> On Wed, 2019-04-03@16:04 -0700, Bart Van Assche wrote:
>>>> Although the code that waits for controllers that are being teared down
>>>> in nvmet_rdma_queue_connect() is fine, lockdep complains about that code.
>>>> Lockdep complains because all release_work instances are assigned the
>>>> same static lockdep key. Avoid that lockdep complains by using dynamic
>>>> lockdep keys instead of static lockdep keys. See also the following
>>>> commits:
>>>> * 87915adc3f0a ("workqueue: re-add lockdep dependencies for flushing").
>>>> * 777dc82395de ("nvmet-rdma: occasionally flush ongoing controller teardown").
>>>> * 108c14858b9e ("locking/lockdep: Add support for dynamic keys").
>>>>
>>>> This patch avoids that lockdep reports the following:
>>>>
>>>> ======================================================
>>>> WARNING: possible circular locking dependency detected
>>>> 4.19.0-dbg #1 Not tainted
>>>> ------------------------------------------------------
>>>> kworker/u12:0/7 is trying to acquire lock:
>>>
>>> Please drop this patch - it is not sufficient to suppress the lockdep complaint.
>>> I will see whether I can come up with a better solution.
>>>
>> 
>> Have you had time to work on this one further? We're seeing the same issue.
> 
> Hi Marta,
> 
> I'm running all NVMe tests on my setup with the attached patch applied.
> 
> Bart.

Thanks Bart! We're going to test it out in our setup and I let you know what
the result is.

Marta