From: Peter Zijlstra <peterz@infradead.org> To: elena.reshetova@intel.com, gregkh@linuxfoundation.org, keescook@chromium.org, arnd@arndb.de, tglx@linutronix.de, mingo@kernel.org, h.peter.anvin@intel.com, will.deacon@arm.com, dwindsor@gmail.com, dhowells@redhat.com, peterz@infradead.org Cc: linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [PATCH 2/5] kref: Implement using refcount_t Date: Fri, 03 Feb 2017 14:26:00 +0100 [thread overview] Message-ID: <20170203132737.365388918@infradead.org> (raw) In-Reply-To: 20170203132558.474916683@infradead.org [-- Attachment #1: peterz-ref-5a.patch --] [-- Type: text/plain, Size: 2539 bytes --] Use the refcount_t 'atomic' type to implement kref, this makes kref more robust by bringing saturation semantics. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- include/linux/kref.h | 29 +++++++++++------------------ 1 file changed, 11 insertions(+), 18 deletions(-) --- 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 */ 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 * { 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 { 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 k { 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 k */ 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_ */
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org> To: elena.reshetova@intel.com, gregkh@linuxfoundation.org, keescook@chromium.org, arnd@arndb.de, tglx@linutronix.de, mingo@kernel.org, h.peter.anvin@intel.com, will.deacon@arm.com, dwindsor@gmail.com, dhowells@redhat.com, peterz@infradead.org Cc: linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [kernel-hardening] [PATCH 2/5] kref: Implement using refcount_t Date: Fri, 03 Feb 2017 14:26:00 +0100 [thread overview] Message-ID: <20170203132737.365388918@infradead.org> (raw) In-Reply-To: 20170203132558.474916683@infradead.org [-- Attachment #1: peterz-ref-5a.patch --] [-- Type: text/plain, Size: 2539 bytes --] Use the refcount_t 'atomic' type to implement kref, this makes kref more robust by bringing saturation semantics. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- include/linux/kref.h | 29 +++++++++++------------------ 1 file changed, 11 insertions(+), 18 deletions(-) --- 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 */ 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 * { 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 { 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 k { 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 k */ 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_ */
next prev parent reply other threads:[~2017-02-03 13:30 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-02-03 13:25 [PATCH 0/5] refcount_t and various related bits Peter Zijlstra 2017-02-03 13:25 ` [kernel-hardening] " Peter Zijlstra 2017-02-03 13:25 ` [PATCH 1/5] refcount_t: A special purpose refcount type Peter Zijlstra 2017-02-03 13:25 ` [kernel-hardening] " Peter Zijlstra 2017-02-03 18:09 ` Kees Cook 2017-02-03 18:09 ` [kernel-hardening] " Kees Cook 2017-02-03 23:37 ` Kees Cook 2017-02-03 23:37 ` [kernel-hardening] " Kees Cook 2017-02-03 13:26 ` Peter Zijlstra [this message] 2017-02-03 13:26 ` [kernel-hardening] [PATCH 2/5] kref: Implement using refcount_t Peter Zijlstra 2017-02-06 13:06 ` Greg KH 2017-02-06 13:06 ` [kernel-hardening] " Greg KH 2017-02-03 13:26 ` [PATCH 3/5] x86: Implement __WARN using UD2 Peter Zijlstra 2017-02-03 13:26 ` [kernel-hardening] " Peter Zijlstra 2017-02-03 13:26 ` [PATCH 4/5] atomic: Introduce atomic_try_cmpxchg() Peter Zijlstra 2017-02-03 13:26 ` [kernel-hardening] " Peter Zijlstra 2017-02-06 4:24 ` Boqun Feng 2017-02-06 4:24 ` [kernel-hardening] " Boqun Feng 2017-02-06 6:32 ` Boqun Feng 2017-02-06 6:32 ` [kernel-hardening] " Boqun Feng 2017-02-06 8:12 ` Peter Zijlstra 2017-02-06 8:12 ` [kernel-hardening] " Peter Zijlstra 2017-02-03 13:26 ` [PATCH 5/5] refcount: Use atomic_try_cmpxchg() Peter Zijlstra 2017-02-03 13:26 ` [kernel-hardening] " Peter Zijlstra
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