From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752366AbcEaKaG (ORCPT ); Tue, 31 May 2016 06:30:06 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:43361 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752121AbcEaKaA (ORCPT ); Tue, 31 May 2016 06:30:00 -0400 Message-Id: <20160531102642.090322196@infradead.org> User-Agent: quilt/0.61-1 Date: Tue, 31 May 2016 12:19:35 +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 10/33] locking,h8300: Implement atomic_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-h8300.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/h8300/include/asm/atomic.h | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-) --- a/arch/h8300/include/asm/atomic.h +++ b/arch/h8300/include/asm/atomic.h @@ -28,6 +28,19 @@ static inline int atomic_##op##_return(i return ret; \ } +#define ATOMIC_FETCH_OP(op, c_op) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + h8300flags flags; \ + int ret; \ + \ + flags = arch_local_irq_save(); \ + ret = v->counter; \ + v->counter c_op i; \ + arch_local_irq_restore(flags); \ + return ret; \ +} + #define ATOMIC_OP(op, c_op) \ static inline void atomic_##op(int i, atomic_t *v) \ { \ @@ -41,17 +54,23 @@ static inline void atomic_##op(int i, at ATOMIC_OP_RETURN(add, +=) ATOMIC_OP_RETURN(sub, -=) -ATOMIC_OP(and, &=) -ATOMIC_OP(or, |=) -ATOMIC_OP(xor, ^=) +#define atomic_fetch_or atomic_fetch_or +#define ATOMIC_OPS(op, c_op) \ + ATOMIC_OP(op, c_op) \ + ATOMIC_FETCH_OP(op, c_op) + +ATOMIC_OPS(and, &=) +ATOMIC_OPS(or, |=) +ATOMIC_OPS(xor, ^=) +ATOMIC_OPS(add, +=) +ATOMIC_OPS(sub, -=) + +#undef ATOMIC_OPS #undef ATOMIC_OP_RETURN #undef ATOMIC_OP -#define atomic_add(i, v) (void)atomic_add_return(i, v) #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0) - -#define atomic_sub(i, v) (void)atomic_sub_return(i, v) #define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0) #define atomic_inc_return(v) atomic_add_return(1, v)