Re: [PATCH] drm/i915/ppgtt: Break loop in gen8_ppgtt_clear_range failure path

From: Jani Nikula <jani.nikula@linux.intel.com>
To: Daniel Vetter <daniel@ffwll.ch>,
	Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915/ppgtt: Break loop in gen8_ppgtt_clear_range failure path
Date: Fri, 26 Jun 2015 13:38:25 +0300	[thread overview]
Message-ID: <87mvzm69ge.fsf@intel.com> (raw)
In-Reply-To: <20150625160423.GT25769@phenom.ffwll.local>

On Thu, 25 Jun 2015, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Thu, Jun 25, 2015 at 06:39:30PM +0300, Mika Kuoppala wrote:
>> Michel Thierry <michel.thierry@intel.com> writes:
>> 
>> > If for some reason [1], the page directory/table does not exist, clear_range
>> > would end up in an infinite while loop.
>> >
>> > Introduced by commit 06fda602dbca ("drm/i915: Create page table allocators").
>> >
>> > [1] This is already being addressed in one of Mika's patches:
>> > http://mid.gmane.org/1432314314-23530-17-git-send-email-mika.kuoppala@intel.com
>> >
>> 
>> We need both.
>> 
>> > Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
>> > Reported-by: John Harrison <john.c.harrison@intel.com>
>> > Signed-off-by: Michel Thierry <michel.thierry@intel.com>
>> 
>> Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
>
> Since the offending commit is in 4.1 this is for Jani.
>
> Cc: stable@vger.kernel.org

Pushed to drm-intel-next-fixes, thanks for the patch and review. Fingers
crossed, I hope I didn't screw up the conflict resolution for nightly...

BR,
Jani.

>
> Cheers, Daniel
>
>> 
>> > ---
>> >  drivers/gpu/drm/i915/i915_gem_gtt.c | 6 +++---
>> >  1 file changed, 3 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
>> > index 2279e03..5dbe928 100644
>> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
>> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
>> > @@ -517,17 +517,17 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
>> >  		struct page *page_table;
>> >  
>> >  		if (WARN_ON(!ppgtt->pdp.page_directory[pdpe]))
>> > -			continue;
>> > +			break;
>> >  
>> >  		pd = ppgtt->pdp.page_directory[pdpe];
>> >  
>> >  		if (WARN_ON(!pd->page_table[pde]))
>> > -			continue;
>> > +			break;
>> >  
>> >  		pt = pd->page_table[pde];
>> >  
>> >  		if (WARN_ON(!pt->page))
>> > -			continue;
>> > +			break;
>> >  
>> >  		page_table = pt->page;
>> >  
>> > -- 
>> > 2.4.4
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Jani Nikula, Intel Open Source Technology Center
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