Re: [PATCH 1/2] drm/tegra: don't take dev->struct_mutex in mmap offset ioctl

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Aug 10, 2015 at 12:30:21PM +0200, Thierry Reding wrote:
> On Wed, Jul 15, 2015 at 03:38:51PM +0200, Daniel Vetter wrote:
> > Since David Herrmann's mmap vma manager rework we don't need to grab
> > dev->struct_mutex any more to prevent races when looking up the mmap
> > offset. Drop it and instead don't forget to use the unref_unlocked
> > variant (since the drm core still cares).
> > 
> > While at it also fix a leak when this ioctl is called on an imported
> > buffer.
> 
> I don't see where the leak's fixed, but other than that this looks good
> to me. Shall I pick this up into the drm/tegra tree?

Copypaste in the commit message from armada, doesn't apply to tegra. Do
you also plan to pick up "drm/tegra: Use
drm_gem_object_reference_unlocked" directly?

And thanks for all the review.
-Daniel

> 
> Thierry
> 
> > Cc: Thierry Reding <thierry.reding@gmail.com>
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > ---
> >  drivers/gpu/drm/tegra/gem.c | 5 -----
> >  1 file changed, 5 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
> > index 01e16e146bfe..827838e64d6e 100644
> > --- a/drivers/gpu/drm/tegra/gem.c
> > +++ b/drivers/gpu/drm/tegra/gem.c
> > @@ -408,12 +408,9 @@ int tegra_bo_dumb_map_offset(struct drm_file *file, struct drm_device *drm,
> >  	struct drm_gem_object *gem;
> >  	struct tegra_bo *bo;
> >  
> > -	mutex_lock(&drm->struct_mutex);
> > -
> >  	gem = drm_gem_object_lookup(drm, file, handle);
> >  	if (!gem) {
> >  		dev_err(drm->dev, "failed to lookup GEM object\n");
> > -		mutex_unlock(&drm->struct_mutex);
> >  		return -EINVAL;
> >  	}
> >  
> > @@ -423,8 +420,6 @@ int tegra_bo_dumb_map_offset(struct drm_file *file, struct drm_device *drm,
> >  
> >  	drm_gem_object_unreference(gem);
> >  
> > -	mutex_unlock(&drm->struct_mutex);
> > -
> >  	return 0;
> >  }
> >  
> > -- 
> > 2.1.4
> > 



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