Re: [Outreachy kernel] [RESEND PATCH] drm: Remove obsolete "This is gross" comment

[Haneen Mohammed <hamohammed.sa@gmail.com>]

On Tue, Sep 26, 2017 at 07:24:38AM +0200, Daniel Vetter wrote:
> On Thu, Sep 21, 2017 at 03:04:24PM -0600, Haneen Mohammed wrote:
> > Remove obsolete comment which was initially added in 2008 to annotate
> > that idr_find() was used before idr_remove() since idr_remove() didn't
> > use to return feedback. The comment now is irrelevant with
> > commit f6cd7daecff5 ("drm: Release driver references to handle before
> > making it available again").
> 
> Personally I'd have added a lot more of the research story you've detailed
> in the private mails, just to show the work you've done. But the terse
> version is ok too ofc.
> 
> > Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
> 
> Applied to drm-misc-next, thanks.
> -Daniel
> 

My bad, I was afraid to add too much details as I always read commit
message should be concise that I then ended up with too little. 

I will try next time to add the necessary information. 

Thank you!
Haneen

> > ---
> >  drivers/gpu/drm/drm_gem.c | 9 ---------
> >  1 file changed, 9 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> > index c55f338..b9bddaa 100644
> > --- a/drivers/gpu/drm/drm_gem.c
> > +++ b/drivers/gpu/drm/drm_gem.c
> > @@ -282,15 +282,6 @@ drm_gem_handle_delete(struct drm_file *filp, u32 handle)
> >  {
> >  	struct drm_gem_object *obj;
> >  
> > -	/* This is gross. The idr system doesn't let us try a delete and
> > -	 * return an error code.  It just spews if you fail at deleting.
> > -	 * So, we have to grab a lock around finding the object and then
> > -	 * doing the delete on it and dropping the refcount, or the user
> > -	 * could race us to double-decrement the refcount and cause a
> > -	 * use-after-free later.  Given the frequency of our handle lookups,
> > -	 * we may want to use ida for number allocation and a hash table
> > -	 * for the pointers, anyway.
> > -	 */
> >  	spin_lock(&filp->table_lock);
> >  
> >  	/* Check if we currently have a reference on the object */
> > -- 
> > 2.7.4
> > 
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> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch