1 files changed, 32 insertions, 0 deletions
diff --git a/linux/lock.c b/linux/lock.c
index 55082727..33b2cc03 100644
--- a/linux/lock.c
+++ b/linux/lock.c
@@ -223,3 +223,35 @@ int drm_finish(struct inode *inode, struct file *filp, unsigned int cmd,
 	drm_flush_unblock(dev, lock.context, lock.flags);
 	return ret;
 }
+
+/* If we get here, it means that the process has called DRM_IOCTL_LOCK
+   without calling DRM_IOCTL_UNLOCK.
+   
+   If the lock is not held, then let the signal proceed as usual.
+   
+   If the lock is held, then set the contended flag and keep the signal
+   blocked.
+   
+
+   Return 1 if the signal should be delivered normally.
+   Return 0 if the signal should be blocked.  */
+
+int drm_notifier(void *priv)
+{
+	drm_sigdata_t *s = (drm_sigdata_t *)priv;
+	unsigned int  old, new, prev;
+
+
+				/* Allow signal delivery if lock isn't held */
+	if (!_DRM_LOCK_IS_HELD(s->lock->lock)
+	    || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context) return 1;
+	
+				/* Otherwise, set flag to force call to
+                                   drmUnlock */
+	do {
+		old  = s->lock->lock;
+		new  = old | _DRM_LOCK_CONT;
+		prev = cmpxchg(&s->lock->lock, old, new);
+	} while (prev != old);
+	return 0;
+}