linux-kernel - Re: [PATCH 01/11] drm/vgem: Use ww_mutex

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Message-ID: <bbbc0476-55ab-b170-fe95-560a379f0249@vodafone.de>
Date:   Mon, 28 Nov 2016 13:58:58 +0100
From:   Christian König <deathsimple@...afone.de>
To:     Nicolai Hähnle <nhaehnle@...il.com>,
        linux-kernel@...r.kernel.org
Cc:     Maarten Lankhorst <dev@...ankhorst.nl>,
        Nicolai Hähnle <Nicolai.Haehnle@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        dri-devel@...ts.freedesktop.org, Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH 01/11] drm/vgem: Use ww_mutex_(un)lock even with a NULL
 context

Am 28.11.2016 um 13:20 schrieb Nicolai Hähnle:
> From: Nicolai Hähnle <Nicolai.Haehnle@....com>
>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Maarten Lankhorst <dev@...ankhorst.nl>
> Cc: Daniel Vetter <daniel@...ll.ch>
> Cc: Chris Wilson <chris@...is-wilson.co.uk>
> Cc: dri-devel@...ts.freedesktop.org
> Signed-off-by: Nicolai Hähnle <Nicolai.Haehnle@....com>
> ---
>   drivers/gpu/drm/vgem/vgem_fence.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/vgem/vgem_fence.c b/drivers/gpu/drm/vgem/vgem_fence.c
> index 488909a..e1d516f 100644
> --- a/drivers/gpu/drm/vgem/vgem_fence.c
> +++ b/drivers/gpu/drm/vgem/vgem_fence.c
> @@ -191,12 +191,12 @@ int vgem_fence_attach_ioctl(struct drm_device *dev,
>   
>   	/* Expose the fence via the dma-buf */
>   	ret = 0;
> -	mutex_lock(&resv->lock.base);
> +	ww_mutex_lock(&resv->lock.base, NULL);

Accessing the base member here is probably superfluous now and will most 
likely raise a warning.

Christian.

>   	if (arg->flags & VGEM_FENCE_WRITE)
>   		reservation_object_add_excl_fence(resv, fence);
>   	else if ((ret = reservation_object_reserve_shared(resv)) == 0)
>   		reservation_object_add_shared_fence(resv, fence);
> -	mutex_unlock(&resv->lock.base);
> +	ww_mutex_unlock(&resv->lock.base);
>   
>   	/* Record the fence in our idr for later signaling */
>   	if (ret == 0) {