drm: Add reference counting to drm_atomic_state
drm_atomic_state has a complicated single owner model that tracks the
single reference from allocation through to destruction on another
thread - or perhaps on a local error path. We can simplify this tracking
by using reference counting (at a cost of a few more atomics). This is
even more beneficial when the lifetime of the state becomes more
convoluted than being passed to a single worker thread for the commit.
v2: Double check !intel atomic_commit functions for missing gets
v3: Update kerneldocs
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161014121833.439-27-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 2373960..5dd7054 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -74,6 +74,8 @@
int
drm_atomic_state_init(struct drm_device *dev, struct drm_atomic_state *state)
{
+ kref_init(&state->ref);
+
/* TODO legacy paths should maybe do a better job about
* setting this appropriately?
*/
@@ -215,22 +217,16 @@
EXPORT_SYMBOL(drm_atomic_state_clear);
/**
- * drm_atomic_state_free - free all memory for an atomic state
- * @state: atomic state to deallocate
+ * __drm_atomic_state_free - free all memory for an atomic state
+ * @ref: This atomic state to deallocate
*
* This frees all memory associated with an atomic state, including all the
* per-object state for planes, crtcs and connectors.
*/
-void drm_atomic_state_free(struct drm_atomic_state *state)
+void __drm_atomic_state_free(struct kref *ref)
{
- struct drm_device *dev;
- struct drm_mode_config *config;
-
- if (!state)
- return;
-
- dev = state->dev;
- config = &dev->mode_config;
+ struct drm_atomic_state *state = container_of(ref, typeof(*state), ref);
+ struct drm_mode_config *config = &state->dev->mode_config;
drm_atomic_state_clear(state);
@@ -243,7 +239,7 @@
kfree(state);
}
}
-EXPORT_SYMBOL(drm_atomic_state_free);
+EXPORT_SYMBOL(__drm_atomic_state_free);
/**
* drm_atomic_get_crtc_state - get crtc state
@@ -1742,7 +1738,7 @@
if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
/*
* Unlike commit, check_only does not clean up state.
- * Below we call drm_atomic_state_free for it.
+ * Below we call drm_atomic_state_put for it.
*/
ret = drm_atomic_check_only(state);
} else if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK) {
@@ -1775,8 +1771,7 @@
goto retry;
}
- if (ret || arg->flags & DRM_MODE_ATOMIC_TEST_ONLY)
- drm_atomic_state_free(state);
+ drm_atomic_state_put(state);
drm_modeset_drop_locks(&ctx);
drm_modeset_acquire_fini(&ctx);