[PATCH] drm/atomic: Make sure lock is held in trylock contexts.

[Maarten Lankhorst]

This will make sure we get a lockdep spat in all cases
even if the context is a complete garbage pointer.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
diff --git a/drivers/gpu/drm/drm_modeset_lock.c 
b/drivers/gpu/drm/drm_modeset_lock.c
index 9abee87c1501..7c9ca2381d78 100644
--- a/drivers/gpu/drm/drm_modeset_lock.c
+++ b/drivers/gpu/drm/drm_modeset_lock.c
@@ -305,6 +305,8 @@ static inline int modeset_lock(struct drm_modeset_lock 
*lock,
        WARN_ON(ctx->contended);

        if (ctx->trylock_only) {
+               lockdep_assert_held(&ctx->ww_ctx);
+
                if (!ww_mutex_trylock(&lock->mutex))
                        return -EBUSY;
                else