Re: [PATCH 01/11] drm/vgem: Use ww_mutex_(un)lock even with a NULL context

[Maarten Lankhorst]

Op 28-11-16 om 13:20 schreef Nicolai HÃhnle:
> From: Nicolai HÃhnle <Nicolai.Haehnle@xxxxxxx>
>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Maarten Lankhorst <dev@xxxxxxxxxxxxxx>
> Cc: Daniel Vetter <daniel@xxxxxxxx>
> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Nicolai HÃhnle <Nicolai.Haehnle@xxxxxxx>
> ---
>  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);
Yuck, can we rename base to __NEVER_TOUCH_DIRECTLY_OUTSIDE_LOCKING_CORE?
It's harder to get them confused like that, even with a null context it's illegal to call mutex_lock/unlock directly.

~Maarten