Commit-ID: 10383aea2f445bce9b2a2b308def08134b438c8e
Gitweb: http://git.kernel.org/tip/10383aea2f445bce9b2a2b308def08134b438c8e
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 14 Nov 2016 18:06:19 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 10 Feb 2017 09:04:19 +0100
kref: Implement 'struct kref' using refcount_t
Use the refcount_t 'atomic' type to implement 'struct kref', this makes kref
more robust by bringing saturation semantics.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/kref.h | 29 +++++++++++------------------
1 file changed, 11 insertions(+), 18 deletions(-)
diff --git a/include/linux/kref.h b/include/linux/kref.h
index 9db9685..f4156f8 100644
--- a/include/linux/kref.h
+++ b/include/linux/kref.h
@@ -15,17 +15,14 @@
#ifndef _KREF_H_
#define _KREF_H_
-#include <linux/bug.h>
-#include <linux/atomic.h>
-#include <linux/kernel.h>
-#include <linux/mutex.h>
#include <linux/spinlock.h>
+#include <linux/refcount.h>
struct kref {
- atomic_t refcount;
+ refcount_t refcount;
};
-#define KREF_INIT(n) { .refcount = ATOMIC_INIT(n), }
+#define KREF_INIT(n) { .refcount = REFCOUNT_INIT(n), }
/**
* kref_init - initialize object.
@@ -33,12 +30,12 @@ struct kref {
*/
static inline void kref_init(struct kref *kref)
{
- atomic_set(&kref->refcount, 1);
+ refcount_set(&kref->refcount, 1);
}
-static inline int kref_read(const struct kref *kref)
+static inline unsigned int kref_read(const struct kref *kref)
{
- return atomic_read(&kref->refcount);
+ return refcount_read(&kref->refcount);
}
/**
@@ -47,11 +44,7 @@ static inline int kref_read(const struct kref *kref)
*/
static inline void kref_get(struct kref *kref)
{
- /* If refcount was 0 before incrementing then we have a race
- * condition when this kref is freeing by some other thread right now.
- * In this case one should use kref_get_unless_zero()
- */
- WARN_ON_ONCE(atomic_inc_return(&kref->refcount) < 2);
+ refcount_inc(&kref->refcount);
}
/**
@@ -75,7 +68,7 @@ static inline int kref_put(struct kref *kref, void (*release)(struct kref *kref)
{
WARN_ON(release == NULL);
- if (atomic_dec_and_test(&kref->refcount)) {
+ if (refcount_dec_and_test(&kref->refcount)) {
release(kref);
return 1;
}
@@ -88,7 +81,7 @@ static inline int kref_put_mutex(struct kref *kref,
{
WARN_ON(release == NULL);
- if (atomic_dec_and_mutex_lock(&kref->refcount, lock)) {
+ if (refcount_dec_and_mutex_lock(&kref->refcount, lock)) {
release(kref);
return 1;
}
@@ -101,7 +94,7 @@ static inline int kref_put_lock(struct kref *kref,
{
WARN_ON(release == NULL);
- if (atomic_dec_and_lock(&kref->refcount, lock)) {
+ if (refcount_dec_and_lock(&kref->refcount, lock)) {
release(kref);
return 1;
}
@@ -126,6 +119,6 @@ static inline int kref_put_lock(struct kref *kref,
*/
static inline int __must_check kref_get_unless_zero(struct kref *kref)
{
- return atomic_add_unless(&kref->refcount, 1, 0);
+ return refcount_inc_not_zero(&kref->refcount);
}
#endif /* _KREF_H_ */
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|