Re: [PATCH] [v2] drm/i915/ppgtt: Never return a NULL context

From: Daniel Vetter <daniel@ffwll.ch>
To: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Intel GFX <intel-gfx@lists.freedesktop.org>,
	Ben Widawsky <ben@bwidawsk.net>,
	Ben Widawsky <benjamin.widawsky@intel.com>
Subject: Re: [PATCH] [v2] drm/i915/ppgtt: Never return a NULL context
Date: Tue, 7 Jan 2014 08:51:10 +0100	[thread overview]
Message-ID: <20140107075110.GC4770@phenom.ffwll.local> (raw)
In-Reply-To: <87ppo9z2ss.fsf@gaia.fi.intel.com>

On Fri, Jan 03, 2014 at 02:07:47PM +0200, Mika Kuoppala wrote:
> Ben Widawsky <benjamin.widawsky@intel.com> writes:
> 
> > It makes all the code which calls into this function way too confusing.
> >
> > v2: Fix destroy IOCTL as well
> >
> > v3: Clarify the other two callers of i915_gem_context_get() to never
> > check for NULL. (Mika)
> >
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=72903
> > Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> 
> Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>

Neither patch subject nor the commit message mention that this fixes a
bug. Also, the Testcase: line at the bottom is missing. I've fixed this
up.
-Daniel

> 
> >  drivers/gpu/drm/i915/i915_gem_context.c    | 12 +++++++++---
> >  drivers/gpu/drm/i915/i915_gem_execbuffer.c |  4 ++--
> >  2 files changed, 11 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
> > index ebe0f67..44dddc00 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_context.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_context.c
> > @@ -526,10 +526,16 @@ void i915_gem_context_close(struct drm_device *dev, struct drm_file *file)
> >  struct i915_hw_context *
> >  i915_gem_context_get(struct drm_i915_file_private *file_priv, u32 id)
> >  {
> > +	struct i915_hw_context *ctx;
> > +
> >  	if (!HAS_HW_CONTEXTS(file_priv->dev_priv->dev))
> >  		return file_priv->private_default_ctx;
> >  
> > -	return (struct i915_hw_context *)idr_find(&file_priv->context_idr, id);
> > +	ctx = (struct i915_hw_context *)idr_find(&file_priv->context_idr, id);
> > +	if (!ctx)
> > +		return ERR_PTR(-ENOENT);
> > +
> > +	return ctx;
> >  }
> >  
> >  static inline int
> > @@ -776,9 +782,9 @@ int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
> >  		return ret;
> >  
> >  	ctx = i915_gem_context_get(file_priv, args->ctx_id);
> > -	if (!ctx) {
> > +	if (IS_ERR(ctx)) {
> >  		mutex_unlock(&dev->struct_mutex);
> > -		return -ENOENT;
> > +		return PTR_ERR(ctx);
> >  	}
> >  
> >  	idr_remove(&ctx->file_priv->context_idr, ctx->id);
> > diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> > index bbff8f9..c30a6ee 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> > @@ -916,7 +916,7 @@ i915_gem_validate_context(struct drm_device *dev, struct drm_file *file,
> >  		return ERR_PTR(-EINVAL);
> >  
> >  	ctx = i915_gem_context_get(file->driver_priv, ctx_id);
> > -	if (IS_ERR_OR_NULL(ctx))
> > +	if (IS_ERR(ctx))
> >  		return ctx;
> >  
> >  	hs = &ctx->hang_stats;
> > @@ -1126,7 +1126,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
> >  	}
> >  
> >  	ctx = i915_gem_validate_context(dev, file, ring, ctx_id);
> > -	if (IS_ERR_OR_NULL(ctx)) {
> > +	if (IS_ERR(ctx)) {
> >  		mutex_unlock(&dev->struct_mutex);
> >  		ret = PTR_ERR(ctx);
> >  		goto pre_mutex_err;
> > -- 
> > 1.8.5.2
> _______________________________________________
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> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch