[Intel-gfx] [PATCH 08/35] drm: Protect dev->filelist with its own mutex

[Alex Deucher]

On Tue, Apr 26, 2016 at 4:52 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Tue, Apr 26, 2016 at 07:29:41PM +0200, Daniel Vetter wrote:
>> amdgpu gained dev->struct_mutex usage, and that's because it's walking
>> the dev->filelist list. Protect that list with it's own lock to take
>> one more step towards getting rid of struct_mutex usage in drivers
>> once and for all.
>>
>> While doing the conversion I noticed that 2 debugfs files in i915
>> completely lacked appropriate locking. Fix that up too.
>>
>> v2: don't forget to switch to drm_gem_object_unreference_unlocked.
>>
>> Cc: Alex Deucher <alexander.deucher at amd.com>
>> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
>
> Just wondering if this worth converting over. Opening/closing isn't
> going to be high contention, I hope, though we can certainly write
> stress cases for it! The goal for drivers to stop using the struct_mutex
> as their BKL, which doesn't preclude keeping the struct_mutex around for
> where it makes sense to have a single mutex rather than a multitude.
>
> I have some misgivings over this, but only because I think its overkill.
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>

I agree with Chris' sentiments.

Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

> -Chris
>
> --
> Chris Wilson, Intel Open Source Technology Centre
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