Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753353AbdFGXkL (ORCPT ); Wed, 7 Jun 2017 19:40:11 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:50574 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752989AbdFGXEc (ORCPT ); Wed, 7 Jun 2017 19:04:32 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Peter Zijlstra , Andrew Morton , Linus Torvalds , "Paul E . McKenney" , Thomas Gleixner , Ingo Molnar , Jiri Slaby , Willy Tarreau Subject: [PATCH 3.10 171/250] locking/static_keys: Add static_key_{en,dis}able() helpers Date: Thu, 8 Jun 2017 00:59:17 +0200 Message-Id: <1496876436-32402-172-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1496876436-32402-1-git-send-email-w@1wt.eu> References: <1496876436-32402-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2283 Lines: 75 From: Peter Zijlstra commit e33886b38cc82a9fc3b2d655dfc7f50467594138 upstream. Add two helpers to make it easier to treat the refcount as boolean. [js] do not involve WARN_ON_ONCE as it causes build failures Suggested-by: Jason Baron Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Jiri Slaby [wt: only backported for use in next fix ; s/static_key_count(key)/atomic_read(&key->enabled)/] Signed-off-by: Willy Tarreau --- include/linux/jump_label.h | 16 ++++++++++++++++ kernel/sched/core.c | 6 ++---- 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index 0976fc4..7f831b2 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -208,4 +208,20 @@ static inline bool static_key_enabled(struct static_key *key) return (atomic_read(&key->enabled) > 0); } +static inline void static_key_enable(struct static_key *key) +{ + int count = atomic_read(&key->enabled); + + if (!count) + static_key_slow_inc(key); +} + +static inline void static_key_disable(struct static_key *key) +{ + int count = atomic_read(&key->enabled); + + if (count) + static_key_slow_dec(key); +} + #endif /* _LINUX_JUMP_LABEL_H */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6a366f9..506e56e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -179,14 +179,12 @@ struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { static void sched_feat_disable(int i) { - if (static_key_enabled(&sched_feat_keys[i])) - static_key_slow_dec(&sched_feat_keys[i]); + static_key_disable(&sched_feat_keys[i]); } static void sched_feat_enable(int i) { - if (!static_key_enabled(&sched_feat_keys[i])) - static_key_slow_inc(&sched_feat_keys[i]); + static_key_enable(&sched_feat_keys[i]); } #else static void sched_feat_disable(int i) { }; -- 2.8.0.rc2.1.gbe9624a