drm/atomic: Only destroy connector states with connection mutex held

Otherwise the connector might have been unplugged and destroyed while
we didn't look. Yet another fallout from DP MST hotplugging that I
didn't consider.

To make sure we get this right add an appropriate WARN_ON to
drm_atomic_state_clear (obviously only when we actually have a state
to clear up). And reorder all the state_clear and backoff calls to
make it work out properly.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 90b2d16..67c1dc8 100644 (file)
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -112,21 +112,24 @@ EXPORT_SYMBOL(drm_atomic_state_alloc);
 void drm_atomic_state_clear(struct drm_atomic_state *state)
 {
        struct drm_device *dev = state->dev;
+       struct drm_mode_config *config = &dev->mode_config;
        int i;
 
        DRM_DEBUG_KMS("Clearing atomic state %p\n", state);
 
-       for (i = 0; i < dev->mode_config.num_connector; i++) {
+       for (i = 0; i < config->num_connector; i++) {
                struct drm_connector *connector = state->connectors[i];
 
                if (!connector)
                        continue;
 
+               WARN_ON(!drm_modeset_is_locked(&config->connection_mutex));
+
                connector->funcs->atomic_destroy_state(connector,
                                                       state->connector_states[i]);
        }
 
-       for (i = 0; i < dev->mode_config.num_crtc; i++) {
+       for (i = 0; i < config->num_crtc; i++) {
                struct drm_crtc *crtc = state->crtcs[i];
 
                if (!crtc)
@@ -136,7 +139,7 @@ void drm_atomic_state_clear(struct drm_atomic_state *state)
                                                  state->crtc_states[i]);
        }
 
-       for (i = 0; i < dev->mode_config.num_total_plane; i++) {
+       for (i = 0; i < config->num_total_plane; i++) {
                struct drm_plane *plane = state->planes[i];
 
                if (!plane)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index fad2b93..0cd0546 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1217,8 +1217,8 @@ fail:
 
        return ret;
 backoff:
-       drm_atomic_legacy_backoff(state);
        drm_atomic_state_clear(state);
+       drm_atomic_legacy_backoff(state);
 
        /*
         * Someone might have exchanged the framebuffer while we dropped locks
@@ -1285,8 +1285,8 @@ fail:
 
        return ret;
 backoff:
-       drm_atomic_legacy_backoff(state);
        drm_atomic_state_clear(state);
+       drm_atomic_legacy_backoff(state);
 
        /*
         * Someone might have exchanged the framebuffer while we dropped locks
@@ -1462,8 +1462,8 @@ fail:
 
        return ret;
 backoff:
-       drm_atomic_legacy_backoff(state);
        drm_atomic_state_clear(state);
+       drm_atomic_legacy_backoff(state);
 
        /*
         * Someone might have exchanged the framebuffer while we dropped locks
@@ -1528,8 +1528,8 @@ fail:
 
        return ret;
 backoff:
-       drm_atomic_legacy_backoff(state);
        drm_atomic_state_clear(state);
+       drm_atomic_legacy_backoff(state);
 
        goto retry;
 }
@@ -1587,8 +1587,8 @@ fail:
 
        return ret;
 backoff:
-       drm_atomic_legacy_backoff(state);
        drm_atomic_state_clear(state);
+       drm_atomic_legacy_backoff(state);
 
        goto retry;
 }
@@ -1646,8 +1646,8 @@ fail:
 
        return ret;
 backoff:
-       drm_atomic_legacy_backoff(state);
        drm_atomic_state_clear(state);
+       drm_atomic_legacy_backoff(state);
 
        goto retry;
 }
@@ -1725,8 +1725,8 @@ fail:
 
        return ret;
 backoff:
-       drm_atomic_legacy_backoff(state);
        drm_atomic_state_clear(state);
+       drm_atomic_legacy_backoff(state);
 
        /*
         * Someone might have exchanged the framebuffer while we dropped locks