[Intel-gfx] [PATCH] drm/i915/ppgtt: Break loop in gen8_ppgtt_clear_range failure path

[Daniel Vetter]

On Thu, Jun 25, 2015 at 06:39:30PM +0300, Mika Kuoppala wrote:
> Michel Thierry <michel.thierry at 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 at linux.intel.com>
> > Reported-by: John Harrison <john.c.harrison at intel.com>
> > Signed-off-by: Michel Thierry <michel.thierry at intel.com>
> 
> Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>

Since the offending commit is in 4.1 this is for Jani.

Cc: stable at vger.kernel.org

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
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch