Now that the media_device can be used by multiple drivers, via devres, we need to be sure that it will be dropped only when all drivers stop using it.
Signed-off-by: Mauro Carvalho Chehab mchehab@osg.samsung.com ---
v2: The kref is now used only when media_device is allocated via the media_device*_devress. This warrants that other drivers won't be affected, and that we can keep media_device_cleanup() balanced with media_device_init().
drivers/media/media-device.c | 117 +++++++++++++++++++++++++-------- drivers/media/usb/au0828/au0828-core.c | 3 +- include/media/media-device.h | 28 ++++++++ sound/usb/media.c | 3 +- 4 files changed, 118 insertions(+), 33 deletions(-)
diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c index c32fa15cc76e..4a97d92a7e7d 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -707,11 +707,16 @@ void media_device_init(struct media_device *mdev) } EXPORT_SYMBOL_GPL(media_device_init);
-void media_device_cleanup(struct media_device *mdev) +static void __media_device_cleanup(struct media_device *mdev) { ida_destroy(&mdev->entity_internal_idx); mdev->entity_internal_idx_max = 0; media_entity_graph_walk_cleanup(&mdev->pm_count_walk); +} + +void media_device_cleanup(struct media_device *mdev) +{ + __media_device_cleanup(mdev); mutex_destroy(&mdev->graph_mutex); } EXPORT_SYMBOL_GPL(media_device_cleanup); @@ -721,6 +726,9 @@ int __must_check __media_device_register(struct media_device *mdev, { int ret;
+ /* Check if mdev was ever registered at all */ + mutex_lock(&mdev->graph_mutex); + /* Register the device node. */ mdev->devnode.fops = &media_device_fops; mdev->devnode.parent = mdev->dev; @@ -731,17 +739,19 @@ int __must_check __media_device_register(struct media_device *mdev,
ret = media_devnode_register(&mdev->devnode, owner); if (ret < 0) - return ret; + goto err;
ret = device_create_file(&mdev->devnode.dev, &dev_attr_model); if (ret < 0) { media_devnode_unregister(&mdev->devnode); - return ret; + goto err; }
dev_dbg(mdev->dev, "Media device registered\n");
- return 0; +err: + mutex_unlock(&mdev->graph_mutex); + return ret; } EXPORT_SYMBOL_GPL(__media_device_register);
@@ -773,24 +783,13 @@ void media_device_unregister_entity_notify(struct media_device *mdev, } EXPORT_SYMBOL_GPL(media_device_unregister_entity_notify);
-void media_device_unregister(struct media_device *mdev) +static void __media_device_unregister(struct media_device *mdev) { struct media_entity *entity; struct media_entity *next; struct media_interface *intf, *tmp_intf; struct media_entity_notify *notify, *nextp;
- if (mdev == NULL) - return; - - mutex_lock(&mdev->graph_mutex); - - /* Check if mdev was ever registered at all */ - if (!media_devnode_is_registered(&mdev->devnode)) { - mutex_unlock(&mdev->graph_mutex); - return; - } - /* Remove all entities from the media device */ list_for_each_entry_safe(entity, next, &mdev->entities, graph_obj.list) __media_device_unregister_entity(entity); @@ -807,38 +806,98 @@ void media_device_unregister(struct media_device *mdev) kfree(intf); }
- mutex_unlock(&mdev->graph_mutex); - - device_remove_file(&mdev->devnode.dev, &dev_attr_model); - media_devnode_unregister(&mdev->devnode); + /* Check if mdev devnode was registered */ + if (media_devnode_is_registered(&mdev->devnode)) { + device_remove_file(&mdev->devnode.dev, &dev_attr_model); + media_devnode_unregister(&mdev->devnode); + }
dev_dbg(mdev->dev, "Media device unregistered\n"); } + +void media_device_unregister(struct media_device *mdev) +{ + if (mdev == NULL) + return; + + mutex_lock(&mdev->graph_mutex); + __media_device_unregister(mdev); + mutex_unlock(&mdev->graph_mutex); +} EXPORT_SYMBOL_GPL(media_device_unregister);
static void media_device_release_devres(struct device *dev, void *res) { }
-struct media_device *media_device_get_devres(struct device *dev) +static void do_media_device_unregister_devres(struct kref *kref) { + struct media_device_devres *mdev_devres; struct media_device *mdev; + int ret;
- mdev = devres_find(dev, media_device_release_devres, NULL, NULL); - if (mdev) - return mdev; + mdev_devres = container_of(kref, struct media_device_devres, kref);
- mdev = devres_alloc(media_device_release_devres, - sizeof(struct media_device), GFP_KERNEL); - if (!mdev) + if (!mdev_devres) + return; + + mdev = &mdev_devres->mdev; + + mutex_lock(&mdev->graph_mutex); + __media_device_unregister(mdev); + __media_device_cleanup(mdev); + mutex_unlock(&mdev->graph_mutex); + mutex_destroy(&mdev->graph_mutex); + + ret = devres_destroy(mdev->dev, media_device_release_devres, + NULL, NULL); + pr_debug("%s: devres_destroy() returned %d\n", __func__, ret); +} + +void media_device_unregister_devres(struct media_device *mdev) +{ + struct media_device_devres *mdev_devres; + + mdev_devres = container_of(mdev, struct media_device_devres, mdev); + kref_put(&mdev_devres->kref, do_media_device_unregister_devres); +} +EXPORT_SYMBOL_GPL(media_device_unregister_devres); + +struct media_device *media_device_get_devres(struct device *dev) +{ + struct media_device_devres *mdev_devres, *ptr; + + mdev_devres = devres_find(dev, media_device_release_devres, NULL, NULL); + if (mdev_devres) { + kref_get(&mdev_devres->kref); + return &mdev_devres->mdev; + } + + mdev_devres = devres_alloc(media_device_release_devres, + sizeof(struct media_device_devres), + GFP_KERNEL); + if (!mdev_devres) return NULL; - return devres_get(dev, mdev, NULL, NULL); + + ptr = devres_get(dev, mdev_devres, NULL, NULL); + if (ptr) + kref_init(&ptr->kref); + else + devres_free(mdev_devres); + + return &ptr->mdev; } EXPORT_SYMBOL_GPL(media_device_get_devres);
struct media_device *media_device_find_devres(struct device *dev) { - return devres_find(dev, media_device_release_devres, NULL, NULL); + struct media_device_devres *mdev_devres; + + mdev_devres = devres_find(dev, media_device_release_devres, NULL, NULL); + if (!mdev_devres) + return NULL; + + return &mdev_devres->mdev; } EXPORT_SYMBOL_GPL(media_device_find_devres);
diff --git a/drivers/media/usb/au0828/au0828-core.c b/drivers/media/usb/au0828/au0828-core.c index 06da73f1ff22..060904ed8f20 100644 --- a/drivers/media/usb/au0828/au0828-core.c +++ b/drivers/media/usb/au0828/au0828-core.c @@ -157,8 +157,7 @@ static void au0828_unregister_media_device(struct au0828_dev *dev) dev->media_dev->enable_source = NULL; dev->media_dev->disable_source = NULL;
- media_device_unregister(dev->media_dev); - media_device_cleanup(dev->media_dev); + media_device_unregister_devres(dev->media_dev); dev->media_dev = NULL; #endif } diff --git a/include/media/media-device.h b/include/media/media-device.h index b21ef244ad3e..e59772ed8494 100644 --- a/include/media/media-device.h +++ b/include/media/media-device.h @@ -23,6 +23,7 @@ #ifndef _MEDIA_DEVICE_H #define _MEDIA_DEVICE_H
+#include <linux/kref.h> #include <linux/list.h> #include <linux/mutex.h>
@@ -382,6 +383,16 @@ struct media_device { unsigned int notification); };
+/** + * struct media_device_devres - Media device device resource + * @mdev: pointer to struct media_device + * @kref: Object refcount + */ +struct media_device_devres { + struct media_device mdev; + struct kref kref; +}; + /* We don't need to include pci.h or usb.h here */ struct pci_dev; struct usb_device; @@ -604,6 +615,19 @@ struct media_device *media_device_get_devres(struct device *dev); */ struct media_device *media_device_find_devres(struct device *dev);
+/** + * media_device_unregister_devres) - Unregister media device allocated as + * as device resource + * + * @dev: pointer to struct &device. + * + * Devices allocated via media_device_get_devres should be de-alocalted + * and freed via this function. Callers should not call + * media_device_unregister() nor media_device_cleanup() on devices + * allocated via media_device_get_devres(). + */ +void media_device_unregister_devres(struct media_device *mdev); + /* Iterate over all entities. */ #define media_device_for_each_entity(entity, mdev) \ list_for_each_entry(entity, &(mdev)->entities, graph_obj.list) @@ -688,6 +712,10 @@ static inline struct media_device *media_device_find_devres(struct device *dev) return NULL; }
+static inline void media_device_unregister_devres(struct media_device *mdev) +{ +} + static inline void media_device_pci_init(struct media_device *mdev, struct pci_dev *pci_dev, char *name) diff --git a/sound/usb/media.c b/sound/usb/media.c index 93a50d01490c..f78955fd0d6e 100644 --- a/sound/usb/media.c +++ b/sound/usb/media.c @@ -311,8 +311,7 @@ void media_snd_device_delete(struct snd_usb_audio *chip) media_snd_mixer_delete(chip);
if (mdev) { - if (media_devnode_is_registered(&mdev->devnode)) - media_device_unregister(mdev); + media_device_unregister_devres(mdev); chip->media_dev = NULL; } }