From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753046AbcEaKbk (ORCPT ); Tue, 31 May 2016 06:31:40 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:43400 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752241AbcEaKaC (ORCPT ); Tue, 31 May 2016 06:30:02 -0400 Message-Id: <20160531102642.956228388@infradead.org> User-Agent: quilt/0.61-1 Date: Tue, 31 May 2016 12:19:49 +0200 From: Peter Zijlstra To: torvalds@linux-foundation.org, mingo@kernel.org, tglx@linutronix.de, will.deacon@arm.com, paulmck@linux.vnet.ibm.com, boqun.feng@gmail.com, waiman.long@hpe.com, fweisbec@gmail.com Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rth@twiddle.net, vgupta@synopsys.com, linux@arm.linux.org.uk, egtvedt@samfundet.no, realmz6@gmail.com, ysato@users.sourceforge.jp, rkuo@codeaurora.org, tony.luck@intel.com, geert@linux-m68k.org, james.hogan@imgtec.com, ralf@linux-mips.org, dhowells@redhat.com, jejb@parisc-linux.org, mpe@ellerman.id.au, schwidefsky@de.ibm.com, dalias@libc.org, davem@davemloft.net, cmetcalf@mellanox.com, jcmvbkbc@gmail.com, arnd@arndb.de, peterz@infradead.org, dbueso@suse.de, fengguang.wu@intel.com Subject: [PATCH -v2 24/33] locking,x86: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() References: <20160531101925.702692792@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=peterz-atomic-fetch-x86.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/atomic.h | 37 ++++++++++++++++++++++++++++++++++--- arch/x86/include/asm/atomic64_32.h | 25 ++++++++++++++++++++++--- arch/x86/include/asm/atomic64_64.h | 35 ++++++++++++++++++++++++++++++++--- 3 files changed, 88 insertions(+), 9 deletions(-) --- a/arch/x86/include/asm/atomic.h +++ b/arch/x86/include/asm/atomic.h @@ -171,6 +171,16 @@ static __always_inline int atomic_sub_re #define atomic_inc_return(v) (atomic_add_return(1, v)) #define atomic_dec_return(v) (atomic_sub_return(1, v)) +static __always_inline int atomic_fetch_add(int i, atomic_t *v) +{ + return xadd(&v->counter, i); +} + +static __always_inline int atomic_fetch_sub(int i, atomic_t *v) +{ + return xadd(&v->counter, -i); +} + static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new) { return cmpxchg(&v->counter, old, new); @@ -190,10 +200,31 @@ static inline void atomic_##op(int i, at : "memory"); \ } -ATOMIC_OP(and) -ATOMIC_OP(or) -ATOMIC_OP(xor) +#define ATOMIC_FETCH_OP(op, c_op) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + int old, val = atomic_read(v); \ + for (;;) { \ + old = atomic_cmpxchg(v, val, val c_op i); \ + if (old == val) \ + break; \ + val = old; \ + } \ + return old; \ +} + +#define ATOMIC_OPS(op, c_op) \ + ATOMIC_OP(op) \ + ATOMIC_FETCH_OP(op, c_op) + +#define atomic_fetch_or atomic_fetch_or + +ATOMIC_OPS(and, &) +ATOMIC_OPS(or , |) +ATOMIC_OPS(xor, ^) +#undef ATOMIC_OPS +#undef ATOMIC_FETCH_OP #undef ATOMIC_OP /** --- a/arch/x86/include/asm/atomic64_32.h +++ b/arch/x86/include/asm/atomic64_32.h @@ -320,10 +320,29 @@ static inline void atomic64_##op(long lo c = old; \ } -ATOMIC64_OP(and, &) -ATOMIC64_OP(or, |) -ATOMIC64_OP(xor, ^) +#define ATOMIC64_FETCH_OP(op, c_op) \ +static inline long long atomic64_fetch_##op(long long i, atomic64_t *v) \ +{ \ + long long old, c = 0; \ + while ((old = atomic64_cmpxchg(v, c, c c_op i)) != c) \ + c = old; \ + return old; \ +} + +ATOMIC64_FETCH_OP(add, +) + +#define atomic64_fetch_sub(i, v) atomic64_fetch_add(-(i), (v)) + +#define ATOMIC64_OPS(op, c_op) \ + ATOMIC64_OP(op, c_op) \ + ATOMIC64_FETCH_OP(op, c_op) + +ATOMIC64_OPS(and, &) +ATOMIC64_OPS(or, |) +ATOMIC64_OPS(xor, ^) +#undef ATOMIC64_OPS +#undef ATOMIC64_FETCH_OP #undef ATOMIC64_OP #endif /* _ASM_X86_ATOMIC64_32_H */ --- a/arch/x86/include/asm/atomic64_64.h +++ b/arch/x86/include/asm/atomic64_64.h @@ -158,6 +158,16 @@ static inline long atomic64_sub_return(l return atomic64_add_return(-i, v); } +static inline long atomic64_fetch_add(long i, atomic64_t *v) +{ + return xadd(&v->counter, i); +} + +static inline long atomic64_fetch_sub(long i, atomic64_t *v) +{ + return xadd(&v->counter, -i); +} + #define atomic64_inc_return(v) (atomic64_add_return(1, (v))) #define atomic64_dec_return(v) (atomic64_sub_return(1, (v))) @@ -229,10 +239,29 @@ static inline void atomic64_##op(long i, : "memory"); \ } -ATOMIC64_OP(and) -ATOMIC64_OP(or) -ATOMIC64_OP(xor) +#define ATOMIC64_FETCH_OP(op, c_op) \ +static inline long atomic64_fetch_##op(long i, atomic64_t *v) \ +{ \ + long old, val = atomic64_read(v); \ + for (;;) { \ + old = atomic64_cmpxchg(v, val, val c_op i); \ + if (old == val) \ + break; \ + val = old; \ + } \ + return old; \ +} + +#define ATOMIC64_OPS(op, c_op) \ + ATOMIC64_OP(op) \ + ATOMIC64_FETCH_OP(op, c_op) + +ATOMIC64_OPS(and, &) +ATOMIC64_OPS(or, |) +ATOMIC64_OPS(xor, ^) +#undef ATOMIC64_OPS +#undef ATOMIC64_FETCH_OP #undef ATOMIC64_OP #endif /* _ASM_X86_ATOMIC64_64_H */