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

[Daniel Vetter]

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 at gmail.com>

Applied to drm-misc-next, thanks.
-Daniel

> ---
>  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