From 5a3ceb861663040f9ef0176df4aaa494bba5e352 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 25 Aug 2008 19:50:19 +0200 Subject: driver-core: use klist for class device list and implement iterator Iterating over entries using callback usually isn't too fun especially when the entry being iterated over can't be manipulated freely. This patch converts class->p->class_devices to klist and implements class device iterator so that the users can freely build their own control structure. The users are also free to call back into class code without worrying about locking. class_for_each_device() and class_find_device() are converted to use the new iterators, so their users don't have to worry about locking anymore either. Note: This depends on klist-dont-iterate-over-deleted-entries patch because class_intf->add/remove_dev() depends on proper synchronization with device removal. Signed-off-by: Tejun Heo Cc: Greg Kroah-Hartman Cc: Jens Axboe Signed-off-by: Jens Axboe --- drivers/base/core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/base/core.c') diff --git a/drivers/base/core.c b/drivers/base/core.c index d021c98605b3..b98cb1416a2d 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -536,7 +536,6 @@ void device_initialize(struct device *dev) klist_init(&dev->klist_children, klist_children_get, klist_children_put); INIT_LIST_HEAD(&dev->dma_pools); - INIT_LIST_HEAD(&dev->node); init_MUTEX(&dev->sem); spin_lock_init(&dev->devres_lock); INIT_LIST_HEAD(&dev->devres_head); @@ -916,7 +915,8 @@ int device_add(struct device *dev) if (dev->class) { mutex_lock(&dev->class->p->class_mutex); /* tie the class to the device */ - list_add_tail(&dev->node, &dev->class->p->class_devices); + klist_add_tail(&dev->knode_class, + &dev->class->p->class_devices); /* notify any interfaces that the device is here */ list_for_each_entry(class_intf, @@ -1032,7 +1032,7 @@ void device_del(struct device *dev) if (class_intf->remove_dev) class_intf->remove_dev(dev, class_intf); /* remove the device from the class list */ - list_del_init(&dev->node); + klist_del(&dev->knode_class); mutex_unlock(&dev->class->p->class_mutex); } device_remove_file(dev, &uevent_attr); -- cgit From 5739411acbaa63a6c22c91e340fdcdbcc7d82a51 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Wed, 3 Sep 2008 18:26:40 +0200 Subject: Driver core: Clarify device cleanup. Make the comments on how to use device_initialize(), device_add() and device_register() a bit clearer - in particular, explicitly note that put_device() must be used once we tried to add the device to the hierarchy. Signed-off-by: Cornelia Huck Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) (limited to 'drivers/base/core.c') diff --git a/drivers/base/core.c b/drivers/base/core.c index b98cb1416a2d..aac91e89d6af 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -523,11 +523,16 @@ static void klist_children_put(struct klist_node *n) * device_initialize - init device structure. * @dev: device. * - * This prepares the device for use by other layers, - * including adding it to the device hierarchy. + * This prepares the device for use by other layers by initializing + * its fields. * It is the first half of device_register(), if called by - * that, though it can also be called separately, so one - * may use @dev's fields (e.g. the refcount). + * that function, though it can also be called separately, so one + * may use @dev's fields. In particular, get_device()/put_device() + * may be used for reference counting of @dev after calling this + * function. + * + * NOTE: Use put_device() to give up your reference instead of freeing + * @dev directly once you have called this function. */ void device_initialize(struct device *dev) { @@ -835,9 +840,13 @@ static void device_remove_sys_dev_entry(struct device *dev) * This is part 2 of device_register(), though may be called * separately _iff_ device_initialize() has been called separately. * - * This adds it to the kobject hierarchy via kobject_add(), adds it + * This adds @dev to the kobject hierarchy via kobject_add(), adds it * to the global and sibling lists for the device, then * adds it to the other relevant subsystems of the driver model. + * + * NOTE: _Never_ directly free @dev after calling this function, even + * if it returned an error! Always use put_device() to give up your + * reference instead. */ int device_add(struct device *dev) { @@ -965,6 +974,10 @@ done: * I.e. you should only call the two helpers separately if * have a clearly defined need to use and refcount the device * before it is added to the hierarchy. + * + * NOTE: _Never_ directly free @dev after calling this function, even + * if it returned an error! Always use put_device() to give up the + * reference initialized in this function instead. */ int device_register(struct device *dev) { -- cgit From 286661b3777897220ecfcd774bccc68a34667f39 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Wed, 3 Sep 2008 18:26:41 +0200 Subject: Driver core: Fix cleanup in device_create_vargs(). If device_register() in device_create_vargs() fails, the device must be cleaned up with put_device() (which is also fine on NULL) instead of kfree(). Signed-off-by: Cornelia Huck Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/base/core.c') diff --git a/drivers/base/core.c b/drivers/base/core.c index aac91e89d6af..9649d1c422a4 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1256,7 +1256,7 @@ struct device *device_create_vargs(struct class *class, struct device *parent, return dev; error: - kfree(dev); + put_device(dev); return ERR_PTR(retval); } EXPORT_SYMBOL_GPL(device_create_vargs); -- cgit From 030c1d2bfcc2187650fb975456ca0b61a5bb77f4 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 8 May 2008 14:41:00 -0700 Subject: kobject: Fix kobject_rename and !CONFIG_SYSFS When looking at kobject_rename I found two bugs with that exist when sysfs support is disabled in the kernel. kobject_rename does not change the name on the kobject when sysfs support is not compiled in. kobject_rename without locking attempts to check the validity of a rename operation, which the kobject layer simply does not have the infrastructure to do. This patch documents the previously unstated requirement of kobject_rename that is the responsibility of the caller to provide mutual exclusion and to be certain that the new_name for the kobject is valid. This patch modifies sysfs_rename_dir in !CONFIG_SYSFS case to call kobject_set_name to actually change the kobject_name. This patch removes the bogus and misleading check in kobject_rename that attempts to see if a rename is valid. The check is bogus because we do not have the proper locking. The check is misleading because it looks like we can and do perform checking at the kobject level that we don't. Signed-off-by: Eric W. Biederman Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/base/core.c') diff --git a/drivers/base/core.c b/drivers/base/core.c index 9649d1c422a4..8c2cc2648f5a 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1327,6 +1327,11 @@ EXPORT_SYMBOL_GPL(device_destroy); * device_rename - renames a device * @dev: the pointer to the struct device to be renamed * @new_name: the new name of the device + * + * It is the responsibility of the caller to provide mutual + * exclusion between two different calls of device_rename + * on the same device to ensure that new_name is valid and + * won't conflict with other devices. */ int device_rename(struct device *dev, char *new_name) { -- cgit