| Message ID | 20231102131056.7256-2-tzimmermann@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: Convert fbdev to DRM client | expand |
Am 02.11.23 um 14:08 schrieb Thomas Zimmermann: > Do not acquire a reference on the module that provides a client's > callback functions in drm_client_init(). The additional reference > prevents the user from unloading the callback functions' module and > thus creating dangling pointers. > > This is only necessary if there is no direct dependency between the > caller of drm_client_init() and the provider of the callbacks in > struct drm_client_funcs. If this case ever existed, it has been > removed from the DRM code. Callers of drm_client_init() also provide > the callback implementation. The lifetime of the clients is tied to > the dependency chain's outer-most module, which is the hardware's > DRM driver. Before client helpers could be unloaded, the driver module > would have to be unloaded, which also unregisters all clients. > > Driver modules that set up DRM clients can now be unloaded. > > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> > Acked-by: Javier Martinez Canillas <javierm@redhat.com> I've added this patch to drm-misc-next. > --- > drivers/gpu/drm/drm_client.c | 12 +----------- > 1 file changed, 1 insertion(+), 11 deletions(-) > > diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c > index c3027115d0552..9403b3f576f7b 100644 > --- a/drivers/gpu/drm/drm_client.c > +++ b/drivers/gpu/drm/drm_client.c > @@ -5,7 +5,6 @@ > > #include <linux/iosys-map.h> > #include <linux/list.h> > -#include <linux/module.h> > #include <linux/mutex.h> > #include <linux/seq_file.h> > #include <linux/slab.h> > @@ -84,16 +83,13 @@ int drm_client_init(struct drm_device *dev, struct drm_client_dev *client, > if (!drm_core_check_feature(dev, DRIVER_MODESET) || !dev->driver->dumb_create) > return -EOPNOTSUPP; > > - if (funcs && !try_module_get(funcs->owner)) > - return -ENODEV; > - > client->dev = dev; > client->name = name; > client->funcs = funcs; > > ret = drm_client_modeset_create(client); > if (ret) > - goto err_put_module; > + return ret; > > ret = drm_client_open(client); > if (ret) > @@ -105,10 +101,6 @@ int drm_client_init(struct drm_device *dev, struct drm_client_dev *client, > > err_free: > drm_client_modeset_free(client); > -err_put_module: > - if (funcs) > - module_put(funcs->owner); > - > return ret; > } > EXPORT_SYMBOL(drm_client_init); > @@ -177,8 +169,6 @@ void drm_client_release(struct drm_client_dev *client) > drm_client_modeset_free(client); > drm_client_close(client); > drm_dev_put(dev); > - if (client->funcs) > - module_put(client->funcs->owner); > } > EXPORT_SYMBOL(drm_client_release); >
diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c index c3027115d0552..9403b3f576f7b 100644 --- a/drivers/gpu/drm/drm_client.c +++ b/drivers/gpu/drm/drm_client.c @@ -5,7 +5,6 @@ #include <linux/iosys-map.h> #include <linux/list.h> -#include <linux/module.h> #include <linux/mutex.h> #include <linux/seq_file.h> #include <linux/slab.h> @@ -84,16 +83,13 @@ int drm_client_init(struct drm_device *dev, struct drm_client_dev *client, if (!drm_core_check_feature(dev, DRIVER_MODESET) || !dev->driver->dumb_create) return -EOPNOTSUPP; - if (funcs && !try_module_get(funcs->owner)) - return -ENODEV; - client->dev = dev; client->name = name; client->funcs = funcs; ret = drm_client_modeset_create(client); if (ret) - goto err_put_module; + return ret; ret = drm_client_open(client); if (ret) @@ -105,10 +101,6 @@ int drm_client_init(struct drm_device *dev, struct drm_client_dev *client, err_free: drm_client_modeset_free(client); -err_put_module: - if (funcs) - module_put(funcs->owner); - return ret; } EXPORT_SYMBOL(drm_client_init); @@ -177,8 +169,6 @@ void drm_client_release(struct drm_client_dev *client) drm_client_modeset_free(client); drm_client_close(client); drm_dev_put(dev); - if (client->funcs) - module_put(client->funcs->owner); } EXPORT_SYMBOL(drm_client_release);