From patchwork Wed May 23 13:35:24 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 136655 Delivered-To: patch@linaro.org Received: by 2002:a2e:9706:0:0:0:0:0 with SMTP id r6-v6csp907345lji; Wed, 23 May 2018 06:36:27 -0700 (PDT) X-Google-Smtp-Source: AB8JxZr5Ka0sSycS1tCCI/pmIjiFx2yYDBs3/U/iwwnTUQBiHGTZGf7gnelg+U4T6KQeuGFypgAk X-Received: by 2002:a17:902:82c3:: with SMTP id u3-v6mr2983495plz.83.1527082587584; Wed, 23 May 2018 06:36:27 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1527082587; cv=none; d=google.com; s=arc-20160816; b=IE/dz5i4rE8BgT2SoH2ZUMV41Pwr6dM/CMQO90SvXfiXZtJs8gGpJJB+rfFgMC1/i1 lAf3jliWRFmeGl3E9rOiQXNZH6VhWxAfgm8nZJGnKq1pP4IlU/Ye9uMAvttJAOTCWg09 vq2vePZmQhtxvbrW0kU0JGhhAiU08JIjiAvF4YhA6AAG3zenZstbhFCCO7zui+QVsPzj NIBx6zuUOO9CwMA4YomKSWR6K8havtnLRcXm41wEMy19S5xluIsMcWtdz4xIi7EIvtE1 HjtEdiB76+lacBbdqaHT87C5d21cNDaLlLDiS4vLG9wcKj2Ty3RVQwkGOrTF54KYe19m gNzg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=FrW3BKzogQRyjDIIZk4w/8vfwIiu3ceE+25LSfBhXIc=; b=dUR5BTZGAJPp5xnpUIrWO7i4uoHcIWLjtB/U90MGiT5ATM2JqhblLGWn+oUdMKE95p yqMNiSPByUY6usBl2cpUu8fjeZNbytk/UYPprDoTHHiiSYqMljC7/dsbmf/QU0rDW5gF i95bEvQCqgpqjf3QVXcxxKh895sbFbuDxOMozJ56+KkLIBtSlGiO80egsFy4ZVJ/Hw4Q z/lEv+GatAYd/1qyogEwLQUSeROhENdELf2z1c4MXcM99FRjkhGy/TPfte38VFXVWpxW 1iabAwuCEOgj96t93w3x6Nmc8xmt7ZU8Y8YvxVQTk0Wm7qmERXto8czxgQ1ruL6dCSIr pd1Q== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id r39-v6si19250494pld.249.2018.05.23.06.36.27; Wed, 23 May 2018 06:36:27 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933154AbeEWNgZ (ORCPT + 30 others); Wed, 23 May 2018 09:36:25 -0400 Received: from foss.arm.com ([217.140.101.70]:55326 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932960AbeEWNgI (ORCPT ); Wed, 23 May 2018 09:36:08 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 94A1480D; Wed, 23 May 2018 06:36:07 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 63C063F24A; Wed, 23 May 2018 06:36:06 -0700 (PDT) From: Mark Rutland To: linux-kernel@vger.kernel.org Cc: Mark Rutland , Boqun Feng , Peter Zijlstra , Will Deacon , Vineet Gupta Subject: [PATCH 04/13] atomics/treewide: make atomic_fetch_add_unless() optional Date: Wed, 23 May 2018 14:35:24 +0100 Message-Id: <20180523133533.1076-5-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180523133533.1076-1-mark.rutland@arm.com> References: <20180523133533.1076-1-mark.rutland@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Several architectures these have a near-identical implementation based on atomic_read() and atomic_cmpxchg() that we can instead define in , so let's do so, using something close to the existing x86 implementation with try_cmpxchg(). Where an architecture provides its own atomic_fetch_add_unless(), it must define a preprocessor symbol for it. The instrumented atomics are updated accordingly. Note that arch/arc's existing atomic_fetch_add_unless() had redundant barriers, as these are already present in its atomic_cmpxchg() implementation. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Boqun Feng Cc: Peter Zijlstra Cc: Will Deacon Cc: Vineet Gupta --- arch/alpha/include/asm/atomic.h | 2 +- arch/arc/include/asm/atomic.h | 28 ---------------------------- arch/arm/include/asm/atomic.h | 11 +---------- arch/arm64/include/asm/atomic.h | 1 - arch/h8300/include/asm/atomic.h | 1 + arch/hexagon/include/asm/atomic.h | 1 + arch/ia64/include/asm/atomic.h | 16 ---------------- arch/m68k/include/asm/atomic.h | 15 --------------- arch/mips/include/asm/atomic.h | 24 ------------------------ arch/parisc/include/asm/atomic.h | 24 ------------------------ arch/powerpc/include/asm/atomic.h | 1 + arch/riscv/include/asm/atomic.h | 1 + arch/s390/include/asm/atomic.h | 15 --------------- arch/sh/include/asm/atomic.h | 25 ------------------------- arch/sparc/include/asm/atomic_32.h | 2 ++ arch/sparc/include/asm/atomic_64.h | 15 --------------- arch/x86/include/asm/atomic.h | 21 --------------------- arch/xtensa/include/asm/atomic.h | 24 ------------------------ include/asm-generic/atomic-instrumented.h | 4 +++- include/asm-generic/atomic.h | 11 ----------- include/linux/atomic.h | 23 +++++++++++++++++++++++ 21 files changed, 34 insertions(+), 231 deletions(-) -- 2.11.0 Reviewed-by: Geert Uytterhoeven Acked-by: Geert Uytterhoeven diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h index eb0f25e4c5dd..4a800a3424a3 100644 --- a/arch/alpha/include/asm/atomic.h +++ b/arch/alpha/include/asm/atomic.h @@ -235,7 +235,7 @@ static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u) smp_mb(); return old; } - +#define atomic_fetch_add_unless atomic_fetch_add_unless /** * atomic64_add_unless - add unless the number is a given value diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h index 1406825b5e7d..60da80481c5d 100644 --- a/arch/arc/include/asm/atomic.h +++ b/arch/arc/include/asm/atomic.h @@ -308,34 +308,6 @@ ATOMIC_OPS(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3) #undef ATOMIC_OP_RETURN #undef ATOMIC_OP -/** - * atomic_fetch_add_unless - add unless the number is a given value - * @v: pointer of type atomic_t - * @a: the amount to add to v... - * @u: ...unless v is equal to u. - * - * Atomically adds @a to @v, so long as it was not @u. - * Returns the old value of @v - */ -#define atomic_fetch_add_unless(v, a, u) \ -({ \ - int c, old; \ - \ - /* \ - * Explicit full memory barrier needed before/after as \ - * LLOCK/SCOND thmeselves don't provide any such semantics \ - */ \ - smp_mb(); \ - \ - c = atomic_read(v); \ - while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c)\ - c = old; \ - \ - smp_mb(); \ - \ - c; \ -}) - #define atomic_inc(v) atomic_add(1, v) #define atomic_dec(v) atomic_sub(1, v) diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h index 02f3894faa48..74460aa00fa0 100644 --- a/arch/arm/include/asm/atomic.h +++ b/arch/arm/include/asm/atomic.h @@ -156,6 +156,7 @@ static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) return oldval; } +#define atomic_fetch_add_unless atomic_fetch_add_unless #else /* ARM_ARCH_6 */ @@ -215,16 +216,6 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, int new) return ret; } -static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - - c = atomic_read(v); - while (c != u && (old = atomic_cmpxchg((v), c, c + a)) != c) - c = old; - return c; -} - #endif /* __LINUX_ARM_ARCH__ */ #define ATOMIC_OPS(op, c_op, asm_op) \ diff --git a/arch/arm64/include/asm/atomic.h b/arch/arm64/include/asm/atomic.h index ad50412889c5..22c8c43d6689 100644 --- a/arch/arm64/include/asm/atomic.h +++ b/arch/arm64/include/asm/atomic.h @@ -125,7 +125,6 @@ #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0) #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0) #define atomic_add_negative(i, v) (atomic_add_return((i), (v)) < 0) -#define atomic_fetch_add_unless(v, a, u) ___atomic_add_unless(v, a, u,) #define atomic_andnot atomic_andnot /* diff --git a/arch/h8300/include/asm/atomic.h b/arch/h8300/include/asm/atomic.h index 4465cfc30a3a..250bb3baac23 100644 --- a/arch/h8300/include/asm/atomic.h +++ b/arch/h8300/include/asm/atomic.h @@ -106,5 +106,6 @@ static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) arch_local_irq_restore(flags); return ret; } +#define atomic_fetch_add_unless atomic_fetch_add_unless #endif /* __ARCH_H8300_ATOMIC __ */ diff --git a/arch/hexagon/include/asm/atomic.h b/arch/hexagon/include/asm/atomic.h index d2feeba93c44..86c67e9adbfa 100644 --- a/arch/hexagon/include/asm/atomic.h +++ b/arch/hexagon/include/asm/atomic.h @@ -196,6 +196,7 @@ static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) ); return __oldval; } +#define atomic_fetch_add_unless atomic_fetch_add_unless #define atomic_inc(v) atomic_add(1, (v)) #define atomic_dec(v) atomic_sub(1, (v)) diff --git a/arch/ia64/include/asm/atomic.h b/arch/ia64/include/asm/atomic.h index 93d48b823220..cfe44086338e 100644 --- a/arch/ia64/include/asm/atomic.h +++ b/arch/ia64/include/asm/atomic.h @@ -215,22 +215,6 @@ ATOMIC64_FETCH_OP(xor, ^) (cmpxchg(&((v)->counter), old, new)) #define atomic64_xchg(v, new) (xchg(&((v)->counter), new)) -static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - c = atomic_read(v); - for (;;) { - if (unlikely(c == (u))) - break; - old = atomic_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } - return c; -} - - static __inline__ long atomic64_add_unless(atomic64_t *v, long a, long u) { long c, old; diff --git a/arch/m68k/include/asm/atomic.h b/arch/m68k/include/asm/atomic.h index 8022d9ea1213..596882cda224 100644 --- a/arch/m68k/include/asm/atomic.h +++ b/arch/m68k/include/asm/atomic.h @@ -211,19 +211,4 @@ static inline int atomic_add_negative(int i, atomic_t *v) return c != 0; } -static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - c = atomic_read(v); - for (;;) { - if (unlikely(c == (u))) - break; - old = atomic_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } - return c; -} - #endif /* __ARCH_M68K_ATOMIC __ */ diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h index 502e691c6393..794734e730d9 100644 --- a/arch/mips/include/asm/atomic.h +++ b/arch/mips/include/asm/atomic.h @@ -274,30 +274,6 @@ static __inline__ int atomic_sub_if_positive(int i, atomic_t * v) #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n))) #define atomic_xchg(v, new) (xchg(&((v)->counter), (new))) -/** - * atomic_fetch_add_unless - add unless the number is a given value - * @v: pointer of type atomic_t - * @a: the amount to add to v... - * @u: ...unless v is equal to u. - * - * Atomically adds @a to @v, so long as it was not @u. - * Returns the old value of @v. - */ -static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - c = atomic_read(v); - for (;;) { - if (unlikely(c == (u))) - break; - old = atomic_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } - return c; -} - #define atomic_dec_return(v) atomic_sub_return(1, (v)) #define atomic_inc_return(v) atomic_add_return(1, (v)) diff --git a/arch/parisc/include/asm/atomic.h b/arch/parisc/include/asm/atomic.h index 3fd0243bf405..b2b6261d05e7 100644 --- a/arch/parisc/include/asm/atomic.h +++ b/arch/parisc/include/asm/atomic.h @@ -77,30 +77,6 @@ static __inline__ int atomic_read(const atomic_t *v) #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n))) #define atomic_xchg(v, new) (xchg(&((v)->counter), new)) -/** - * atomic_fetch_add_unless - add unless the number is a given value - * @v: pointer of type atomic_t - * @a: the amount to add to v... - * @u: ...unless v is equal to u. - * - * Atomically adds @a to @v, so long as it was not @u. - * Returns the old value of @v. - */ -static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - c = atomic_read(v); - for (;;) { - if (unlikely(c == (u))) - break; - old = atomic_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } - return c; -} - #define ATOMIC_OP(op, c_op) \ static __inline__ void atomic_##op(int i, atomic_t *v) \ { \ diff --git a/arch/powerpc/include/asm/atomic.h b/arch/powerpc/include/asm/atomic.h index e59620ee4f6b..b5646c079c16 100644 --- a/arch/powerpc/include/asm/atomic.h +++ b/arch/powerpc/include/asm/atomic.h @@ -248,6 +248,7 @@ static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u) return t; } +#define atomic_fetch_add_unless atomic_fetch_add_unless /** * atomic_inc_not_zero - increment unless the number is zero diff --git a/arch/riscv/include/asm/atomic.h b/arch/riscv/include/asm/atomic.h index 18259e90f57e..5f161daefcd2 100644 --- a/arch/riscv/include/asm/atomic.h +++ b/arch/riscv/include/asm/atomic.h @@ -349,6 +349,7 @@ static __always_inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) : "memory"); return prev; } +#define atomic_fetch_add_unless atomic_fetch_add_unless #ifndef CONFIG_GENERIC_ATOMIC64 static __always_inline long __atomic64_add_unless(atomic64_t *v, long a, long u) diff --git a/arch/s390/include/asm/atomic.h b/arch/s390/include/asm/atomic.h index 66dac30a4fe1..26c6b713a7a3 100644 --- a/arch/s390/include/asm/atomic.h +++ b/arch/s390/include/asm/atomic.h @@ -90,21 +90,6 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, int new) return __atomic_cmpxchg(&v->counter, old, new); } -static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - c = atomic_read(v); - for (;;) { - if (unlikely(c == u)) - break; - old = atomic_cmpxchg(v, c, c + a); - if (likely(old == c)) - break; - c = old; - } - return c; -} - #define ATOMIC64_INIT(i) { (i) } static inline long atomic64_read(const atomic64_t *v) diff --git a/arch/sh/include/asm/atomic.h b/arch/sh/include/asm/atomic.h index ef45931ebac5..422fac764ca1 100644 --- a/arch/sh/include/asm/atomic.h +++ b/arch/sh/include/asm/atomic.h @@ -45,31 +45,6 @@ #define atomic_xchg(v, new) (xchg(&((v)->counter), new)) #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n))) -/** - * atomic_fetch_add_unless - add unless the number is a given value - * @v: pointer of type atomic_t - * @a: the amount to add to v... - * @u: ...unless v is equal to u. - * - * Atomically adds @a to @v, so long as it was not @u. - * Returns the old value of @v. - */ -static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - c = atomic_read(v); - for (;;) { - if (unlikely(c == (u))) - break; - old = atomic_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } - - return c; -} - #endif /* CONFIG_CPU_J2 */ #endif /* __ASM_SH_ATOMIC_H */ diff --git a/arch/sparc/include/asm/atomic_32.h b/arch/sparc/include/asm/atomic_32.h index a58f4b43bcc7..9d7a15acc0c5 100644 --- a/arch/sparc/include/asm/atomic_32.h +++ b/arch/sparc/include/asm/atomic_32.h @@ -30,6 +30,8 @@ int atomic_xchg(atomic_t *, int); int atomic_fetch_add_unless(atomic_t *, int, int); void atomic_set(atomic_t *, int); +#define atomic_fetch_add_unless atomic_fetch_add_unless + #define atomic_set_release(v, i) atomic_set((v), (i)) #define atomic_read(v) READ_ONCE((v)->counter) diff --git a/arch/sparc/include/asm/atomic_64.h b/arch/sparc/include/asm/atomic_64.h index 07830a316464..e4f1c93db31f 100644 --- a/arch/sparc/include/asm/atomic_64.h +++ b/arch/sparc/include/asm/atomic_64.h @@ -89,21 +89,6 @@ static inline int atomic_xchg(atomic_t *v, int new) return xchg(&v->counter, new); } -static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - c = atomic_read(v); - for (;;) { - if (unlikely(c == (u))) - break; - old = atomic_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } - return c; -} - #define atomic64_cmpxchg(v, o, n) \ ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n))) #define atomic64_xchg(v, new) (xchg(&((v)->counter), new)) diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h index 84ed0bd76aef..616327ac9d39 100644 --- a/arch/x86/include/asm/atomic.h +++ b/arch/x86/include/asm/atomic.h @@ -253,27 +253,6 @@ static inline int arch_atomic_fetch_xor(int i, atomic_t *v) return val; } -/** - * arch_atomic_fetch_add_unless - add unless the number is already a given value - * @v: pointer of type atomic_t - * @a: the amount to add to v... - * @u: ...unless v is equal to u. - * - * Atomically adds @a to @v, so long as @v was not already @u. - * Returns the old value of @v. - */ -static __always_inline int arch_atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c = arch_atomic_read(v); - - do { - if (unlikely(c == u)) - break; - } while (!arch_atomic_try_cmpxchg(v, &c, c + a)); - - return c; -} - #ifdef CONFIG_X86_32 # include #else diff --git a/arch/xtensa/include/asm/atomic.h b/arch/xtensa/include/asm/atomic.h index 4188e56c06c9..f4c9f82c40c6 100644 --- a/arch/xtensa/include/asm/atomic.h +++ b/arch/xtensa/include/asm/atomic.h @@ -274,30 +274,6 @@ ATOMIC_OPS(xor) #define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n))) #define atomic_xchg(v, new) (xchg(&((v)->counter), new)) -/** - * atomic_fetch_add_unless - add unless the number is a given value - * @v: pointer of type atomic_t - * @a: the amount to add to v... - * @u: ...unless v is equal to u. - * - * Atomically adds @a to @v, so long as it was not @u. - * Returns the old value of @v. - */ -static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - c = atomic_read(v); - for (;;) { - if (unlikely(c == (u))) - break; - old = atomic_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } - return c; -} - #endif /* __KERNEL__ */ #endif /* _XTENSA_ATOMIC_H */ diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h index 52b7dcb41769..6e0818c182e2 100644 --- a/include/asm-generic/atomic-instrumented.h +++ b/include/asm-generic/atomic-instrumented.h @@ -84,12 +84,14 @@ static __always_inline bool atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 ne } #endif +#ifdef arch_atomic_fetch_add_unless +#define atomic_fetch_add_unless atomic_fetch_add_unless static __always_inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) { kasan_check_write(v, sizeof(*v)); return arch_atomic_fetch_add_unless(v, a, u); } - +#endif static __always_inline bool atomic64_add_unless(atomic64_t *v, s64 a, s64 u) { diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h index 10051ed6d088..757e45821220 100644 --- a/include/asm-generic/atomic.h +++ b/include/asm-generic/atomic.h @@ -221,15 +221,4 @@ static inline void atomic_dec(atomic_t *v) #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v))) #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) -#ifndef atomic_fetch_add_unless -static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - c = atomic_read(v); - while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c) - c = old; - return c; -} -#endif - #endif /* __ASM_GENERIC_ATOMIC_H */ diff --git a/include/linux/atomic.h b/include/linux/atomic.h index e83f12ec7f2d..1105c0b37f27 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -520,6 +520,29 @@ #endif /* xchg_relaxed */ /** + * atomic_fetch_add_unless - add unless the number is already a given value + * @v: pointer of type atomic_t + * @a: the amount to add to v... + * @u: ...unless v is equal to u. + * + * Atomically adds @a to @v, so long as @v was not already @u. + * Returns original value of @v + */ +#ifndef atomic_fetch_add_unless +static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) +{ + int c = atomic_read(v); + + do { + if (unlikely(c == u)) + break; + } while (!atomic_try_cmpxchg(v, &c, c + a)); + + return c; +} +#endif + +/** * atomic_add_unless - add unless the number is already a given value * @v: pointer of type atomic_t * @a: the amount to add to v...