Re: [PATCH] drm/i915: Only free the unpin_work if cancelled before being run

From: Daniel Vetter <daniel@ffwll.ch>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: Only free the unpin_work if cancelled before being run
Date: Tue, 17 Apr 2012 11:47:38 +0200	[thread overview]
Message-ID: <20120417094738.GD4104@phenom.ffwll.local> (raw)
In-Reply-To: <1334654978-16021-1-git-send-email-chris@chris-wilson.co.uk>

On Tue, Apr 17, 2012 at 10:29:38AM +0100, Chris Wilson wrote:
> The unpin worker frees it work struct and so during intel_crtc_disable
s/disable/destroy/

> we should only also free the work struct if cancel_work_sync() reports
> that it successfully cancelled the work prior to it being executed and
> thus avoid the double free.
> 
> The impact is only for people unloading modules during a fullscreen game
> or movie playback, so extremely small.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/i915/intel_display.c |    4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 8298b72..78390e8 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -7602,10 +7602,8 @@ static void intel_crtc_destroy(struct drm_crtc *crtc)
>  	intel_crtc->unpin_work = NULL;
>  	spin_unlock_irqrestore(&dev->event_lock, flags);
>  
> -	if (work) {
> -		cancel_work_sync(&work->work);
> +	if (work && cancel_work_sync(&work->work))
>  		kfree(work);
> -	}
>  
>  	drm_crtc_cleanup(crtc);
>  
> -- 
> 1.7.10
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48