Re: [PATCH 3/5] drm/i915: Extract gen6 aliasing ppgtt code

[Ben Widawsky <ben@bwidawsk.net>]

On Sat, 29 Dec 2012 11:49:01 +0000
Chris Wilson <chris@chris-wilson.co.uk> wrote:

> On Fri, 28 Dec 2012 20:27:27 -0800, Ben Widawsky <ben@bwidawsk.net>
> wrote:
> > This refactor clearly identifies the GEN specific portion of the
> > aliased ppgtt code. Aside from some of the gen specific parts being
> > extracted, it also preps us for an upcoming patch that pulls out
> > the size, which has some nice benefits.
> 
> Error handling looks a little wonky.

I've not looked in much detail yet, but I'll assume you're right since
I did this pretty quickly. So given that assumption, what do you think
of the patches, useful, or waste of code complexity?

> 
> > 
> > Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> > ---
> >  drivers/gpu/drm/i915/i915_gem_gtt.c | 51
> > ++++++++++++++++++++++--------------- 1 file changed, 30
> > insertions(+), 21 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > b/drivers/gpu/drm/i915/i915_gem_gtt.c index 94d21aa..3b1bff1 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -108,29 +108,20 @@ static void i915_ppgtt_clear_range(struct
> > i915_hw_ppgtt *ppgtt, }
> >  }
> >  
> > -static int i915_gem_init_aliasing_ppgtt(struct drm_device *dev)
> > +static int gen6_init_aliasing_ppgtt(struct i915_hw_ppgtt *ppgtt)
> >  {
> > +	struct drm_device *dev = ppgtt->dev;
> >  	struct drm_i915_private *dev_priv = dev->dev_private;
> > -	struct i915_hw_ppgtt *ppgtt;
> >  	unsigned first_pd_entry_in_global_pt;
> > -	int i;
> > -	int ret = -ENOMEM;
> > +	int i, ret = -ENOMEM;
> >  
> >  	/* ppgtt PDEs reside in the global gtt pagetable, which
> > has 512*1024
> >  	 * entries. For aliasing ppgtt support we just steal them
> > at the end for
> >  	 * now. */
> >  	first_pd_entry_in_global_pt =
> > dev_priv->mm.gtt->gtt_total_entries - I915_PPGTT_PD_ENTRIES; -
> > -	ppgtt = kzalloc(sizeof(*ppgtt), GFP_KERNEL);
> > -	if (!ppgtt)
> > -		return ret;
> > -
> > -	ppgtt->dev = dev;
> >  	ppgtt->num_pd_entries = I915_PPGTT_PD_ENTRIES;
> >  	ppgtt->pt_pages = kzalloc(sizeof(struct page
> > *)*ppgtt->num_pd_entries, GFP_KERNEL);
> > -	if (!ppgtt->pt_pages)
> > -		goto err_ppgtt;
> 
> I think you still want this...
>   
> > @@ -185,9 +171,32 @@ err_pt_alloc:
> >  		if (ppgtt->pt_pages[i])
> >  			__free_page(ppgtt->pt_pages[i]);
> >  	}
> > -	kfree(ppgtt->pt_pages);
> > -err_ppgtt:
> > -	kfree(ppgtt);
> > +
> > +	if (!ppgtt->pt_pages)
> > +		kfree(ppgtt->pt_pages);
> 
> And will want to reconsider this chunk.
> -Chris
>