[Intel-gfx] [PATCH] [v2] drm/i915: Check for get_pages instead of shmem (filp)

[Daniel Vetter]

On Wed, Feb 10, 2016 at 09:39:33AM -0800, Ben Widawsky wrote:
> On Wed, Feb 10, 2016 at 04:23:08PM +0000, Chris Wilson wrote:
> > On Wed, Feb 10, 2016 at 07:42:23AM -0800, Ben Widawsky wrote:
> > > Do you guys get the CI mails? This version has regressions. v1 did not. I don't
> > > know what to trust.
> > 
> > I didn't even see v2 itself!
> >  
> > > On Tue, Feb 09, 2016 at 11:44:12AM -0800, Ben Widawsky wrote:
> > > > This behavior of checking for a shmem backed GEM object was introduced here:
> > > > commit 4c914c0c7c787b8f730128a8cdcca9c50b0784ab
> > > > Author: Brad Volkin <bradley.d.volkin at intel.com>
> > > > Date:   Tue Feb 18 10:15:45 2014 -0800
> > > > 
> > > >     drm/i915: Refactor shmem pread setup
> > > > 
> > > > It is possible for an object to not be a shmem backed GEM object (for example
> > > > userptr objects). An example of how we hit this failure can be found through
> > > > copy_batch() in the command parser because we allocate a userptr object for the
> > > > batch which contains privileged instructions. Userptr calls
> > > > drm_gem_private_object_init() which explicitly sets the filp to none.
> > > > 
> > > > NOTE: I manually retyped this from a test machine. So I haven't even compiled
> > > > this exact patch.
> > > > 
> > > > v2: Use same logic as from a2a4f916c2f (Kristian, Dave Gordon)
> > > > 
> > > > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > > > Cc: Kristian Høgsberg <krh at bitplanet.net>
> > > > Cc: Dave Gordon <david.s.gordon at intel.com>
> > > > Signed-off-by: Ben Widawsky <benjamin.widawsky at intel.com>
> > > > Tested-by: Jordan Justen <jordan.l.justen at intel.com> (v1)
> > > > Reviewed-by: Jordan Justen <jordan.l.justen at intel.com> (v1)
> > 
> > > > ---
> > > >  drivers/gpu/drm/i915/i915_gem.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > > > index e9b19bc..7fd79b0 100644
> > > > --- a/drivers/gpu/drm/i915/i915_gem.c
> > > > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > > > @@ -489,7 +489,7 @@ int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj,
> > > >  
> > > >  	*needs_clflush = 0;
> > > >  
> > > > -	if (!obj->base.filp)
> > > > +	if (WARN_ON((obj->ops->flags & I915_GEM_OBJECT_HAS_STRUCT_PAGE) == 0))
> > 
> > Don't use WARN_ON, there is code (or will be) where we use
> > prepare_shmem_read/write to determine if we can use the shmem paths.
> > 
> > Also i915_gem_obj_prepare_shmem_write() requires the same treatment.
> > 
> > My apologies I had this patch but appear to have accidentally squashed
> > it whilst rebasing. Thanks!
> > -Chris
> > 
> 
> So... is someone going to land this fix? We need it.

Queued for -next, thanks for the patch. Aside: We have about 15 committers
by now, Chris being one of them. No need to hang in there waiting for lazy
me to undig myself from the latest CI fire.
-Daniel
> 
> -- 
> Ben Widawsky, Intel Open Source Technology Center
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch