drm: Tighten locking in drm_mode_getconnector
- Modeset state needs mode_config->connection mutex, that covers
figuring out the encoder, and reading properties (since in the
atomic case those need to look at connector->state).
- Don't hold any locks for stuff that's invariant (i.e. possible
connectors).
- Same for connector lookup and unref, those don't need any locks.
- And finally the probe stuff is only protected by mode_config->mutex.
While at it updated the kerneldoc for these fields in drm_connector
and add docs explaining what's protected by which locks.
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161213230814.19598-10-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index b404012..3115db2 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -1163,36 +1163,9 @@
memset(&u_mode, 0, sizeof(struct drm_mode_modeinfo));
- mutex_lock(&dev->mode_config.mutex);
-
connector = drm_connector_lookup(dev, out_resp->connector_id);
- if (!connector) {
- ret = -ENOENT;
- goto out_unlock;
- }
-
- for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++)
- if (connector->encoder_ids[i] != 0)
- encoders_count++;
-
- if (out_resp->count_modes == 0) {
- connector->funcs->fill_modes(connector,
- dev->mode_config.max_width,
- dev->mode_config.max_height);
- }
-
- /* delayed so we get modes regardless of pre-fill_modes state */
- list_for_each_entry(mode, &connector->modes, head)
- if (drm_mode_expose_to_userspace(mode, file_priv))
- mode_count++;
-
- out_resp->connector_id = connector->base.id;
- out_resp->connector_type = connector->connector_type;
- out_resp->connector_type_id = connector->connector_type_id;
- out_resp->mm_width = connector->display_info.width_mm;
- out_resp->mm_height = connector->display_info.height_mm;
- out_resp->subpixel = connector->display_info.subpixel_order;
- out_resp->connection = connector->status;
+ if (!connector)
+ return -ENOENT;
drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
encoder = drm_connector_get_encoder(connector);
@@ -1201,6 +1174,55 @@
else
out_resp->encoder_id = 0;
+ ret = drm_mode_object_get_properties(&connector->base, file_priv->atomic,
+ (uint32_t __user *)(unsigned long)(out_resp->props_ptr),
+ (uint64_t __user *)(unsigned long)(out_resp->prop_values_ptr),
+ &out_resp->count_props);
+ drm_modeset_unlock(&dev->mode_config.connection_mutex);
+ if (ret)
+ goto out_unref;
+
+ for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++)
+ if (connector->encoder_ids[i] != 0)
+ encoders_count++;
+
+ if ((out_resp->count_encoders >= encoders_count) && encoders_count) {
+ copied = 0;
+ encoder_ptr = (uint32_t __user *)(unsigned long)(out_resp->encoders_ptr);
+ for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+ if (connector->encoder_ids[i] != 0) {
+ if (put_user(connector->encoder_ids[i],
+ encoder_ptr + copied)) {
+ ret = -EFAULT;
+ goto out_unref;
+ }
+ copied++;
+ }
+ }
+ }
+ out_resp->count_encoders = encoders_count;
+
+ out_resp->connector_id = connector->base.id;
+ out_resp->connector_type = connector->connector_type;
+ out_resp->connector_type_id = connector->connector_type_id;
+
+ mutex_lock(&dev->mode_config.mutex);
+ if (out_resp->count_modes == 0) {
+ connector->funcs->fill_modes(connector,
+ dev->mode_config.max_width,
+ dev->mode_config.max_height);
+ }
+
+ out_resp->mm_width = connector->display_info.width_mm;
+ out_resp->mm_height = connector->display_info.height_mm;
+ out_resp->subpixel = connector->display_info.subpixel_order;
+ out_resp->connection = connector->status;
+
+ /* delayed so we get modes regardless of pre-fill_modes state */
+ list_for_each_entry(mode, &connector->modes, head)
+ if (drm_mode_expose_to_userspace(mode, file_priv))
+ mode_count++;
+
/*
* This ioctl is called twice, once to determine how much space is
* needed, and the 2nd time to fill it.
@@ -1222,36 +1244,10 @@
}
}
out_resp->count_modes = mode_count;
-
- ret = drm_mode_object_get_properties(&connector->base, file_priv->atomic,
- (uint32_t __user *)(unsigned long)(out_resp->props_ptr),
- (uint64_t __user *)(unsigned long)(out_resp->prop_values_ptr),
- &out_resp->count_props);
- if (ret)
- goto out;
-
- if ((out_resp->count_encoders >= encoders_count) && encoders_count) {
- copied = 0;
- encoder_ptr = (uint32_t __user *)(unsigned long)(out_resp->encoders_ptr);
- for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
- if (connector->encoder_ids[i] != 0) {
- if (put_user(connector->encoder_ids[i],
- encoder_ptr + copied)) {
- ret = -EFAULT;
- goto out;
- }
- copied++;
- }
- }
- }
- out_resp->count_encoders = encoders_count;
-
out:
- drm_modeset_unlock(&dev->mode_config.connection_mutex);
-
- drm_connector_unreference(connector);
-out_unlock:
mutex_unlock(&dev->mode_config.mutex);
+out_unref:
+ drm_connector_unreference(connector);
return ret;
}