Re: [PATCH 6/6] drm/omap: protect omap_crtc's event with event_lock spinlock

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

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On 11/04/14 10:23, Archit Taneja wrote:
> The vblank_cb callback and the page_flip ioctl can occur together in different
> CPU contexts. vblank_cb uses takes tje drm device's event_lock spinlock when
> sending the vblank event and updating omap_crtc->event and omap_crtc->od_fb.
> 
> Use the same spinlock in page_flip, to make sure the above omap_crtc parameters
> are configured sequentially.
> 
> Signed-off-by: Archit Taneja <archit@ti.com>
> ---
>  drivers/gpu/drm/omapdrm/omap_crtc.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c
> index d74c72c..9c7af42 100644
> --- a/drivers/gpu/drm/omapdrm/omap_crtc.c
> +++ b/drivers/gpu/drm/omapdrm/omap_crtc.c
> @@ -350,6 +350,7 @@ static int omap_crtc_page_flip_locked(struct drm_crtc *crtc,
>  	struct drm_device *dev = crtc->dev;
>  	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
>  	struct drm_gem_object *bo;
> +	unsigned long flags;
>  
>  	DBG("%d -> %d (event=%p)", crtc->fb ? crtc->fb->base.id : -1,
>  			fb->base.id, event);
> @@ -359,9 +360,12 @@ static int omap_crtc_page_flip_locked(struct drm_crtc *crtc,
>  		return -EINVAL;
>  	}
>  
> +	spin_lock_irqsave(&dev->event_lock, flags);
> +
>  	omap_crtc->event = event;
>  	omap_crtc->old_fb = crtc->fb = fb;
>  
> +	spin_unlock_irqrestore(&dev->event_lock, flags);

There's

if (omap_crtc->old_fb)

just above the code you changed. Shouldn't that also be inside the spinlock?

Also, the description contains a few typos.

 Tomi




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