[PATCH 05/21] drm/omap: add a comment why locking is missing
Tomi Valkeinen
tomi.valkeinen at ti.com
Thu Feb 26 05:20:13 PST 2015
unpin_worker() calls omap_framebuffer_unpin() without any locks, which
looks very suspicious. However, both pin and unpin are always called via
the driver's private workqueue, so the access is synchronized that way.
Add a comment to make this clear.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
---
drivers/gpu/drm/omapdrm/omap_plane.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/gpu/drm/omapdrm/omap_plane.c b/drivers/gpu/drm/omapdrm/omap_plane.c
index ee8e2b3a117e..1f4f2b866379 100644
--- a/drivers/gpu/drm/omapdrm/omap_plane.c
+++ b/drivers/gpu/drm/omapdrm/omap_plane.c
@@ -71,6 +71,10 @@ static void unpin_worker(struct drm_flip_work *work, void *val)
container_of(work, struct omap_plane, unpin_work);
struct drm_device *dev = omap_plane->base.dev;
+ /*
+ * omap_framebuffer_pin/unpin are always called from priv->wq,
+ * so there's no need for locking here.
+ */
omap_framebuffer_unpin(val);
mutex_lock(&dev->mode_config.mutex);
drm_framebuffer_unreference(val);
--
2.3.0
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