Re: [PATCH 07/26] drm/i915: clean up PPGTT init error path

[Ben Widawsky <ben@bwidawsk.net>]

On Sat, Mar 22, 2014 at 08:58:29PM +0000, Chris Wilson wrote:
> On Sat, Mar 22, 2014 at 12:43:28PM -0700, Ben Widawsky wrote:
> > On Tue, Mar 18, 2014 at 08:44:28AM +0000, Chris Wilson wrote:
> > > On Mon, Mar 17, 2014 at 10:48:39PM -0700, Ben Widawsky wrote:
> > > > The old code (I'm having trouble finding the commit) had a reason for
> > > > doing things when there was an error, and would continue on, thus the
> > > > !ret. For the newer code however, this looks completely silly.
> > > > 
> > > > Follow the normal idiom of if (ret) return ret.
> > > > 
> > > > Also, put the pde wiring in the gen specific init, now that GEN8 exists.
> > > > 
> > > > Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> > > > ---
> > > >  drivers/gpu/drm/i915/i915_gem_gtt.c | 22 +++++++++-------------
> > > >  1 file changed, 9 insertions(+), 13 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > > > index 1620211..5f73284 100644
> > > > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > > > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > > > @@ -1202,6 +1202,8 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
> > > >  	ppgtt->pd_offset =
> > > >  		ppgtt->node.start / PAGE_SIZE * sizeof(gen6_gtt_pte_t);
> > > >  
> > > > +	gen6_write_pdes(ppgtt);
> > > > +
> > > >  	ppgtt->base.clear_range(&ppgtt->base, 0, ppgtt->base.total, true);
> > > >  
> > > >  	DRM_DEBUG_DRIVER("Allocated pde space (%ldM) at GTT entry: %lx\n",
> > > > @@ -1226,20 +1228,14 @@ int i915_gem_init_ppgtt(struct drm_device *dev, struct i915_hw_ppgtt *ppgtt)
> > > >  	else
> > > >  		BUG();
> > > >  
> > > > -	if (!ret) {
> > > > -		struct drm_i915_private *dev_priv = dev->dev_private;
> > > > -		kref_init(&ppgtt->ref);
> > > > -		drm_mm_init(&ppgtt->base.mm, ppgtt->base.start,
> > > > -			    ppgtt->base.total);
> > > > -		i915_init_vm(dev_priv, &ppgtt->base);
> > > > -		if (INTEL_INFO(dev)->gen < 8) {
> > > > -			gen6_write_pdes(ppgtt);
> > > > -			DRM_DEBUG("Adding PPGTT at offset %x\n",
> > > > -				  ppgtt->pd_offset << 10);
> > > > -		}
> > > > -	}
> > > > +	if (ret)
> > > > +		return ret;
> > > >  
> > > > -	return ret;
> > > > +	kref_init(&ppgtt->ref);
> > > > +	drm_mm_init(&ppgtt->base.mm, ppgtt->base.start, ppgtt->base.total);
> > > > +	i915_init_vm(dev_priv, &ppgtt->base);
> > > 
> > > Didn't we just delete the dev_priv local variable?
> > > -Chris
> > 
> > The important part is that the pde writes moved. (The DRM debug is also
> > dropped). As for this code, I just wanted to get rid of the if (!ret)
> > block. It looks weird.
> > 
> > Maybe I didn't get what you're asking though.
> 
> I was wondering if this patch compiles because of the removal of the
> dev_priv local variable. (Or if the original was a shadow.)
> -Chris

Ah, of course. Yes, there was a shadowed dev_priv. I think it was
merge/rebase fail either by myself or Daniel when the original patches
were merged.

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

-- 
Ben Widawsky, Intel Open Source Technology Center