diff options
| -rw-r--r-- | drivers/gpu/drm/drm_drv.c | 6 | ||||
| -rw-r--r-- | drivers/gpu/drm/drm_file.c | 48 | ||||
| -rw-r--r-- | drivers/gpu/drm/drm_internal.h | 1 |
3 files changed, 47 insertions, 8 deletions
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index b8f716e61037..7b1a628d1f6e 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -946,7 +946,8 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags) struct drm_driver *driver = dev->driver; int ret; - mutex_lock(&drm_global_mutex); + if (drm_dev_needs_global_mutex(dev)) + mutex_lock(&drm_global_mutex); ret = drm_minor_register(dev, DRM_MINOR_RENDER); if (ret) @@ -986,7 +987,8 @@ err_minors: drm_minor_unregister(dev, DRM_MINOR_PRIMARY); drm_minor_unregister(dev, DRM_MINOR_RENDER); out_unlock: - mutex_unlock(&drm_global_mutex); + if (drm_dev_needs_global_mutex(dev)) + mutex_unlock(&drm_global_mutex); return ret; } EXPORT_SYMBOL(drm_dev_register); diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c index 80d556402ab4..c4c704e01961 100644 --- a/drivers/gpu/drm/drm_file.c +++ b/drivers/gpu/drm/drm_file.c @@ -51,6 +51,37 @@ /* from BKL pushdown */ DEFINE_MUTEX(drm_global_mutex); +bool drm_dev_needs_global_mutex(struct drm_device *dev) +{ + /* + * Legacy drivers rely on all kinds of BKL locking semantics, don't + * bother. They also still need BKL locking for their ioctls, so better + * safe than sorry. + */ + if (drm_core_check_feature(dev, DRIVER_LEGACY)) + return true; + + /* + * The deprecated ->load callback must be called after the driver is + * already registered. This means such drivers rely on the BKL to make + * sure an open can't proceed until the driver is actually fully set up. + * Similar hilarity holds for the unload callback. + */ + if (dev->driver->load || dev->driver->unload) + return true; + + /* + * Drivers with the lastclose callback assume that it's synchronized + * against concurrent opens, which again needs the BKL. The proper fix + * is to use the drm_client infrastructure with proper locking for each + * client. + */ + if (dev->driver->lastclose) + return true; + + return false; +} + /** * DOC: file operations * @@ -378,9 +409,10 @@ int drm_open(struct inode *inode, struct file *filp) if (IS_ERR(minor)) return PTR_ERR(minor); - mutex_lock(&drm_global_mutex); - dev = minor->dev; + if (drm_dev_needs_global_mutex(dev)) + mutex_lock(&drm_global_mutex); + if (!atomic_fetch_inc(&dev->open_count)) need_setup = 1; @@ -398,13 +430,15 @@ int drm_open(struct inode *inode, struct file *filp) } } - mutex_unlock(&drm_global_mutex); + if (drm_dev_needs_global_mutex(dev)) + mutex_unlock(&drm_global_mutex); return 0; err_undo: atomic_dec(&dev->open_count); - mutex_unlock(&drm_global_mutex); + if (drm_dev_needs_global_mutex(dev)) + mutex_unlock(&drm_global_mutex); drm_minor_release(minor); return retcode; } @@ -444,7 +478,8 @@ int drm_release(struct inode *inode, struct file *filp) struct drm_minor *minor = file_priv->minor; struct drm_device *dev = minor->dev; - mutex_lock(&drm_global_mutex); + if (drm_dev_needs_global_mutex(dev)) + mutex_lock(&drm_global_mutex); DRM_DEBUG("open_count = %d\n", atomic_read(&dev->open_count)); @@ -453,7 +488,8 @@ int drm_release(struct inode *inode, struct file *filp) if (atomic_dec_and_test(&dev->open_count)) drm_lastclose(dev); - mutex_unlock(&drm_global_mutex); + if (drm_dev_needs_global_mutex(dev)) + mutex_unlock(&drm_global_mutex); drm_minor_release(minor); diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h index 6937bf923f05..aeec2e68d772 100644 --- a/drivers/gpu/drm/drm_internal.h +++ b/drivers/gpu/drm/drm_internal.h @@ -41,6 +41,7 @@ struct drm_printer; /* drm_file.c */ extern struct mutex drm_global_mutex; +bool drm_dev_needs_global_mutex(struct drm_device *dev); struct drm_file *drm_file_alloc(struct drm_minor *minor); void drm_file_free(struct drm_file *file); void drm_lastclose(struct drm_device *dev); |