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-rw-r--r--linux/lock.c32
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;
+}