Release 4.11 include/linux/kref.h
/*
* kref.h - library routines for handling generic reference counted objects
*
* Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (C) 2004 IBM Corp.
*
* based on kobject.h which was:
* Copyright (C) 2002-2003 Patrick Mochel <mochel@osdl.org>
* Copyright (C) 2002-2003 Open Source Development Labs
*
* This file is released under the GPLv2.
*
*/
#ifndef _KREF_H_
#define _KREF_H_
#include <linux/spinlock.h>
#include <linux/refcount.h>
struct kref {
refcount_t refcount;
};
#define KREF_INIT(n) { .refcount = REFCOUNT_INIT(n), }
/**
* kref_init - initialize object.
* @kref: object in question.
*/
static inline void kref_init(struct kref *kref)
{
refcount_set(&kref->refcount, 1);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Peter Zijlstra | 14 | 63.64% | 2 | 66.67% |
| Greg Kroah-Hartman | 8 | 36.36% | 1 | 33.33% |
| Total | 22 | 100.00% | 3 | 100.00% |
static inline unsigned int kref_read(const struct kref *kref)
{
return refcount_read(&kref->refcount);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Peter Zijlstra | 23 | 100.00% | 2 | 100.00% |
| Total | 23 | 100.00% | 2 | 100.00% |
/**
* kref_get - increment refcount for object.
* @kref: object.
*/
static inline void kref_get(struct kref *kref)
{
refcount_inc(&kref->refcount);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Peter Zijlstra | 12 | 60.00% | 2 | 50.00% |
| Greg Kroah-Hartman | 8 | 40.00% | 2 | 50.00% |
| Total | 20 | 100.00% | 4 | 100.00% |
/**
* kref_put - decrement refcount for object.
* @kref: object.
* @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.
*
* Decrement the refcount, and if 0, call release().
* Return 1 if the object was removed, otherwise return 0. Beware, if this
* function returns 0, you still can not count on the kref from remaining in
* memory. Only use the return value if you want to see if the kref is now
* gone, not present.
*/
static inline int kref_put(struct kref *kref, void (*release)(struct kref *kref))
{
WARN_ON(release == NULL);
if (refcount_dec_and_test(&kref->refcount)) {
release(kref);
return 1;
}
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Peter Zijlstra | 35 | 64.81% | 3 | 50.00% |
| Greg Kroah-Hartman | 19 | 35.19% | 3 | 50.00% |
| Total | 54 | 100.00% | 6 | 100.00% |
static inline int kref_put_mutex(struct kref *kref,
void (*release)(struct kref *kref),
struct mutex *lock)
{
WARN_ON(release == NULL);
if (refcount_dec_and_mutex_lock(&kref->refcount, lock)) {
release(kref);
return 1;
}
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Al Viro | 47 | 77.05% | 1 | 33.33% |
| Peter Zijlstra | 14 | 22.95% | 2 | 66.67% |
| Total | 61 | 100.00% | 3 | 100.00% |
static inline int kref_put_lock(struct kref *kref,
void (*release)(struct kref *kref),
spinlock_t *lock)
{
WARN_ON(release == NULL);
if (refcount_dec_and_lock(&kref->refcount, lock)) {
release(kref);
return 1;
}
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Peter Zijlstra | 34 | 56.67% | 2 | 66.67% |
| Al Viro | 26 | 43.33% | 1 | 33.33% |
| Total | 60 | 100.00% | 3 | 100.00% |
/**
* kref_get_unless_zero - Increment refcount for object unless it is zero.
* @kref: object.
*
* Return non-zero if the increment succeeded. Otherwise return 0.
*
* This function is intended to simplify locking around refcounting for
* objects that can be looked up from a lookup structure, and which are
* removed from that lookup structure in the object destructor.
* Operations on such objects require at least a read lock around
* lookup + kref_get, and a write lock around kref_put + remove from lookup
* structure. Furthermore, RCU implementations become extremely tricky.
* With a lookup followed by a kref_get_unless_zero *with return value check*
* locking in the kref_put path can be deferred to the actual removal from
* the lookup structure and RCU lookups become trivial.
*/
static inline int __must_check kref_get_unless_zero(struct kref *kref)
{
return refcount_inc_not_zero(&kref->refcount);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Thomas Hellstrom | 21 | 95.45% | 1 | 50.00% |
| Peter Zijlstra | 1 | 4.55% | 1 | 50.00% |
| Total | 22 | 100.00% | 2 | 100.00% |
#endif /* _KREF_H_ */
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Peter Zijlstra | 148 | 49.83% | 6 | 42.86% |
| Al Viro | 73 | 24.58% | 1 | 7.14% |
| Greg Kroah-Hartman | 51 | 17.17% | 4 | 28.57% |
| Thomas Hellstrom | 22 | 7.41% | 1 | 7.14% |
| Linus Torvalds | 2 | 0.67% | 1 | 7.14% |
| Robert P. J. Day | 1 | 0.34% | 1 | 7.14% |
| Total | 297 | 100.00% | 14 | 100.00% |
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