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drm: prevent double-(un)registration for connectors

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If we're unlucky then the registration from a hotplugged connector
might race with the final registration step on driver load. And since
MST topology discover is asynchronous that's even somewhat likely.

v2: Also update the kerneldoc for @registered!

v3: Review from Chris:
- Improve kerneldoc for late_register/early_unregister callbacks.
- Use mutex_destroy.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161218133545.2106-1-daniel.vetter@ffwll.ch
This commit is contained in:
Daniel Vetter
2016-12-18 14:35:45 +01:00
parent 2ab8c5f8c0
commit e73ab00e9a
2 changed files with 30 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/gpu/drm/drm_connector.c
View File

@@ -224,6 +224,7 @@ int drm_connector_init(struct drm_device *dev,
INIT_LIST_HEAD(&connector->probed_modes);
INIT_LIST_HEAD(&connector->modes);
mutex_init(&connector->mutex);
connector->edid_blob_ptr = NULL;
connector->status = connector_status_unknown;
@@ -359,6 +360,8 @@ void drm_connector_cleanup(struct drm_connector *connector)
connector->funcs->atomic_destroy_state(connector,
connector->state);
mutex_destroy(&connector->mutex);
memset(connector, 0, sizeof(*connector));
}
EXPORT_SYMBOL(drm_connector_cleanup);
@@ -374,14 +377,15 @@ EXPORT_SYMBOL(drm_connector_cleanup);
*/
int drm_connector_register(struct drm_connector *connector)
{
int ret;
int ret = 0;
mutex_lock(&connector->mutex);
if (connector->registered)
return 0;
goto unlock;
ret = drm_sysfs_connector_add(connector);
if (ret)
return ret;
goto unlock;
ret = drm_debugfs_connector_add(connector);
if (ret) {
@@ -397,12 +401,14 @@ int drm_connector_register(struct drm_connector *connector)
drm_mode_object_register(connector->dev, &connector->base);
connector->registered = true;
return 0;
goto unlock;
err_debugfs:
drm_debugfs_connector_remove(connector);
err_sysfs:
drm_sysfs_connector_remove(connector);
unlock:
mutex_unlock(&connector->mutex);
return ret;
}
EXPORT_SYMBOL(drm_connector_register);
@@ -415,8 +421,11 @@ EXPORT_SYMBOL(drm_connector_register);
*/
void drm_connector_unregister(struct drm_connector *connector)
{
if (!connector->registered)
mutex_lock(&connector->mutex);
if (!connector->registered) {
mutex_unlock(&connector->mutex);
return;
}
if (connector->funcs->early_unregister)
connector->funcs->early_unregister(connector);
@@ -425,6 +434,7 @@ void drm_connector_unregister(struct drm_connector *connector)
drm_debugfs_connector_remove(connector);
connector->registered = false;
mutex_unlock(&connector->mutex);
}
EXPORT_SYMBOL(drm_connector_unregister);