From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757393Ab1IAB2X (ORCPT ); Wed, 31 Aug 2011 21:28:23 -0400 Received: from mail-wy0-f174.google.com ([74.125.82.174]:50286 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757377Ab1IAB2I (ORCPT ); Wed, 31 Aug 2011 21:28:08 -0400 From: Shan Hai To: akpm@linux-foundation.org Cc: eric.dumazet@gmail.com, vapier@gentoo.org, asharma@fb.com, linux-kernel@vger.kernel.org, Shan Hai Subject: [PATCH 1/1] lib:atomic64 using raw_spin_lock_irq[save|resotre] for atomicity Date: Thu, 1 Sep 2011 09:28:00 +0800 Message-Id: <1314840480-25182-2-git-send-email-haishan.bai@gmail.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1314840480-25182-1-git-send-email-haishan.bai@gmail.com> References: <1314840480-25182-1-git-send-email-haishan.bai@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The spin_lock_irq[save|restore] could break the atomicity of the atomic64_* operations in the PREEMPT-RT configuration, because the spin_lock_irq[save|restore] themselves are preemptable in the PREEMPT-RT, using raw variant of the spin lock could provide the atomicity that atomic64_* need. Signed-off-by: Shan Hai --- lib/atomic64.c | 40 ++++++++++++++++++++-------------------- 1 files changed, 20 insertions(+), 20 deletions(-) diff --git a/lib/atomic64.c b/lib/atomic64.c index e12ae0d..26f524a 100644 --- a/lib/atomic64.c +++ b/lib/atomic64.c @@ -48,9 +48,9 @@ long long atomic64_read(const atomic64_t *v) spinlock_t *lock = lock_addr(v); long long val; - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); val = v->counter; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); return val; } EXPORT_SYMBOL(atomic64_read); @@ -60,9 +60,9 @@ void atomic64_set(atomic64_t *v, long long i) unsigned long flags; spinlock_t *lock = lock_addr(v); - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); v->counter = i; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); } EXPORT_SYMBOL(atomic64_set); @@ -71,9 +71,9 @@ void atomic64_add(long long a, atomic64_t *v) unsigned long flags; spinlock_t *lock = lock_addr(v); - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); v->counter += a; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); } EXPORT_SYMBOL(atomic64_add); @@ -83,9 +83,9 @@ long long atomic64_add_return(long long a, atomic64_t *v) spinlock_t *lock = lock_addr(v); long long val; - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); val = v->counter += a; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); return val; } EXPORT_SYMBOL(atomic64_add_return); @@ -95,9 +95,9 @@ void atomic64_sub(long long a, atomic64_t *v) unsigned long flags; spinlock_t *lock = lock_addr(v); - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); v->counter -= a; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); } EXPORT_SYMBOL(atomic64_sub); @@ -107,9 +107,9 @@ long long atomic64_sub_return(long long a, atomic64_t *v) spinlock_t *lock = lock_addr(v); long long val; - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); val = v->counter -= a; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); return val; } EXPORT_SYMBOL(atomic64_sub_return); @@ -120,11 +120,11 @@ long long atomic64_dec_if_positive(atomic64_t *v) spinlock_t *lock = lock_addr(v); long long val; - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); val = v->counter - 1; if (val >= 0) v->counter = val; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); return val; } EXPORT_SYMBOL(atomic64_dec_if_positive); @@ -135,11 +135,11 @@ long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n) spinlock_t *lock = lock_addr(v); long long val; - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); val = v->counter; if (val == o) v->counter = n; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); return val; } EXPORT_SYMBOL(atomic64_cmpxchg); @@ -150,10 +150,10 @@ long long atomic64_xchg(atomic64_t *v, long long new) spinlock_t *lock = lock_addr(v); long long val; - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); val = v->counter; v->counter = new; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); return val; } EXPORT_SYMBOL(atomic64_xchg); @@ -164,12 +164,12 @@ int atomic64_add_unless(atomic64_t *v, long long a, long long u) spinlock_t *lock = lock_addr(v); int ret = 0; - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); if (v->counter != u) { v->counter += a; ret = 1; } - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); return ret; } EXPORT_SYMBOL(atomic64_add_unless); -- 1.7.4.1