From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757258AbaAHRBH (ORCPT ); Wed, 8 Jan 2014 12:01:07 -0500 Received: from g1t0028.austin.hp.com ([15.216.28.35]:45974 "EHLO g1t0028.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757136AbaAHRAh (ORCPT ); Wed, 8 Jan 2014 12:00:37 -0500 From: Waiman Long To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Arnd Bergmann Cc: linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Steven Rostedt , Andrew Morton , Michel Lespinasse , Andi Kleen , Rik van Riel , "Paul E. McKenney" , Linus Torvalds , Raghavendra K T , George Spelvin , Tim Chen , "Aswin Chandramouleeswaran\"" , Scott J Norton , Waiman Long Subject: [PATCH v8 4/4] qrwlock: Use smp_store_release() in write_unlock() Date: Wed, 8 Jan 2014 11:59:36 -0500 Message-Id: <1389200376-62792-5-git-send-email-Waiman.Long@hp.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1389200376-62792-1-git-send-email-Waiman.Long@hp.com> References: <1389200376-62792-1-git-send-email-Waiman.Long@hp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch modifies the queue_write_unlock() function to use the new smp_store_release() function in another pending patch. It also removes the temporary implementation of smp_load_acquire() and smp_store_release() function in qrwlock.c. This patch should only be merged if PeterZ's linux-arch patch patch was merged. Signed-off-by: Waiman Long Reviewed-by: Paul E. McKenney --- include/asm-generic/qrwlock.h | 4 +--- kernel/locking/qrwlock.c | 34 ---------------------------------- 2 files changed, 1 insertions(+), 37 deletions(-) diff --git a/include/asm-generic/qrwlock.h b/include/asm-generic/qrwlock.h index 2b9a7b4..4d4bd04 100644 --- a/include/asm-generic/qrwlock.h +++ b/include/asm-generic/qrwlock.h @@ -179,9 +179,7 @@ static inline void queue_write_unlock(struct qrwlock *lock) /* * Make sure that none of the critical section will be leaked out. */ - smp_mb__before_clear_bit(); - ACCESS_ONCE(lock->cnts.writer) = 0; - smp_mb__after_clear_bit(); + smp_store_release(&lock->cnts.writer, 0) } /* diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c index 1b3ffb2..3d3ba2b 100644 --- a/kernel/locking/qrwlock.c +++ b/kernel/locking/qrwlock.c @@ -48,40 +48,6 @@ # define arch_mutex_cpu_relax() cpu_relax() #endif -#ifndef smp_load_acquire -# ifdef CONFIG_X86 -# define smp_load_acquire(p) \ - ({ \ - typeof(*p) ___p1 = ACCESS_ONCE(*p); \ - barrier(); \ - ___p1; \ - }) -# else -# define smp_load_acquire(p) \ - ({ \ - typeof(*p) ___p1 = ACCESS_ONCE(*p); \ - smp_mb(); \ - ___p1; \ - }) -# endif -#endif - -#ifndef smp_store_release -# ifdef CONFIG_X86 -# define smp_store_release(p, v) \ - do { \ - barrier(); \ - ACCESS_ONCE(*p) = v; \ - } while (0) -# else -# define smp_store_release(p, v) \ - do { \ - smp_mb(); \ - ACCESS_ONCE(*p) = v; \ - } while (0) -# endif -#endif - /* * If an xadd (exchange-add) macro isn't available, simulate one with * the atomic_add_return() function. -- 1.7.1