diff options
| -rw-r--r-- | Documentation/kobject.txt | 10 | ||||
| -rw-r--r-- | drivers/base/core.c | 3 | ||||
| -rw-r--r-- | include/linux/kref.h | 5 | ||||
| -rw-r--r-- | lib/kobject.c | 2 |
4 files changed, 10 insertions, 10 deletions
diff --git a/Documentation/kobject.txt b/Documentation/kobject.txt index fc9485d79061..ff4c25098119 100644 --- a/Documentation/kobject.txt +++ b/Documentation/kobject.txt @@ -279,10 +279,14 @@ such a method has a form like:: One important point cannot be overstated: every kobject must have a release() method, and the kobject must persist (in a consistent state) until that method is called. If these constraints are not met, the code is -flawed. Note that the kernel will warn you if you forget to provide a +flawed. Note that the kernel will warn you if you forget to provide a release() method. Do not try to get rid of this warning by providing an -"empty" release function; you will be mocked mercilessly by the kobject -maintainer if you attempt this. +"empty" release function. + +If all your cleanup function needs to do is call kfree(), then you must +create a wrapper function which uses container_of() to upcast to the correct +type (as shown in the example above) and then calls kfree() on the overall +structure. Note, the name of the kobject is available in the release function, but it must NOT be changed within this callback. Otherwise there will be a memory diff --git a/drivers/base/core.c b/drivers/base/core.c index ed145fbfeddf..e2285059161d 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -897,8 +897,7 @@ static void device_release(struct kobject *kobj) else if (dev->class && dev->class->dev_release) dev->class->dev_release(dev); else - WARN(1, KERN_ERR "Device '%s' does not have a release() " - "function, it is broken and must be fixed.\n", + WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/kobject.txt.\n", dev_name(dev)); kfree(p); } diff --git a/include/linux/kref.h b/include/linux/kref.h index 29220724bf1c..cb00a0268061 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -53,10 +53,7 @@ static inline void kref_get(struct kref *kref) * @release: pointer to the function that will clean up the object when the * last reference to the object is released. * This pointer is required, and it is not acceptable to pass kfree - * in as this function. If the caller does pass kfree to this - * function, you will be publicly mocked mercilessly by the kref - * maintainer, and anyone else who happens to notice it. You have - * been warned. + * in as this function. * * Decrement the refcount, and if 0, call release(). * Return 1 if the object was removed, otherwise return 0. Beware, if this diff --git a/lib/kobject.c b/lib/kobject.c index 97d86dc17c42..b72e00fd7d09 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -639,7 +639,7 @@ static void kobject_cleanup(struct kobject *kobj) kobject_name(kobj), kobj, __func__, kobj->parent); if (t && !t->release) - pr_debug("kobject: '%s' (%p): does not have a release() function, it is broken and must be fixed.\n", + pr_debug("kobject: '%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/kobject.txt.\n", kobject_name(kobj), kobj); /* send "remove" if the caller did not do it but sent "add" */ |