From mboxrd@z Thu Jan  1 00:00:00 1970
From: Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH] drm: Do not use BUG_ON(!spin_is_locked())
Date: Mon, 11 Aug 2014 07:06:48 -0700
Message-ID: <53E8CDF8.2060008@roeck-us.net>
References: <1407731491-22446-1-git-send-email-linux@roeck-us.net> <alpine.DEB.2.02.1408110439580.15519@chino.kir.corp.google.com>
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To: David Rientjes <rientjes@google.com>
Cc: David Airlie <airlied@linux.ie>, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
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On 08/11/2014 04:45 AM, David Rientjes wrote:
> On Sun, 10 Aug 2014, Guenter Roeck wrote:
>
>> spin_is_locked() always returns false in uniprocessor configurations
>> and can therefore not be used with BUG_ON. Replace it with
>> assert_spin_locked(), which exists for that very purpose.
>>
>
> It may be helpful to assess whether any of these sites should be converted
> to lockdep_assert_held() so they have no cost when lockdep isn't enabled
> but still reveal problems when debugging.
>
>

Possibly, but that would need to be done by someone with better knowledge
about locking and the code than me.

Guenter