From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754592Ab1KDJ2h (ORCPT ); Fri, 4 Nov 2011 05:28:37 -0400 Received: from mail-gx0-f174.google.com ([209.85.161.174]:40697 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752576Ab1KDJ2g (ORCPT ); Fri, 4 Nov 2011 05:28:36 -0400 From: Yong Zhang To: linux-kernel@vger.kernel.org Cc: sergey.senozhatsky@gmail.com, bp@alien8.de, Peter Zijlstra , Ingo Molnar Subject: [RFC PATCH 2/4] lockdep: Let register_lock_class() can be called with/without graph_lock Date: Fri, 4 Nov 2011 17:26:28 +0800 Message-Id: <1320398790-21663-3-git-send-email-yong.zhang0@gmail.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1320398790-21663-1-git-send-email-yong.zhang0@gmail.com> References: <1320398790-21663-1-git-send-email-yong.zhang0@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Will be used in later patch which fix some race condition in lock_set_class(). Signed-off-by: Yong Zhang Cc: Peter Zijlstra Cc: Ingo Molnar --- kernel/lockdep.c | 14 +++++++++----- 1 files changed, 9 insertions(+), 5 deletions(-) diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 4a16b0a..e7d38fa 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -711,9 +711,13 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) * Register a lock's class in the hash-table, if the class is not present * yet. Otherwise we look it up. We cache the result in the lock object * itself, so actual lookup of the hash should be once per lock object. + * + * NOTE: register_lock_class() can be called with/without graph_lock hold + * depending on @locked. But it will release graph_lock before return. */ static inline struct lock_class * -register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) +register_lock_class(struct lockdep_map *lock, unsigned int subclass, + int force, int locked) { struct lockdep_subclass_key *key; struct list_head *hash_head; @@ -741,7 +745,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) hash_head = classhashentry(key); raw_local_irq_save(flags); - if (!graph_lock()) { + if (!locked && !graph_lock()) { raw_local_irq_restore(flags); return NULL; } @@ -2986,7 +2990,7 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name, return; if (subclass) - register_lock_class(lock, subclass, 1); + register_lock_class(lock, subclass, 1, 0); } EXPORT_SYMBOL_GPL(lockdep_init_map); @@ -3032,7 +3036,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, * Not cached? */ if (unlikely(!class)) { - class = register_lock_class(lock, subclass, 0); + class = register_lock_class(lock, subclass, 0, 0); if (!class) return 0; } @@ -3276,7 +3280,7 @@ found_it: /* optimizing for lock_set_subclass() */ if (key) { lockdep_init_map(lock, name, key, 0); - register_lock_class(lock, subclass, 0); + register_lock_class(lock, subclass, 0, 0); } curr->lockdep_depth = i; -- 1.7.5.4