From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752078Ab1FXDx0 (ORCPT ); Thu, 23 Jun 2011 23:53:26 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:33363 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751548Ab1FXDxZ (ORCPT ); Thu, 23 Jun 2011 23:53:25 -0400 Date: Thu, 23 Jun 2011 20:53:11 -0700 From: "Paul E. McKenney" To: Frederic Weisbecker Cc: LKML , Peter Zijlstra , Thomas Gleixner , Lai Jiangshan , Ingo Molnar Subject: Re: [PATCH 0/3 v3] rcu: Detect rcu uses under extended quiescent state Message-ID: <20110624035311.GB2266@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1308870760-14153-1-git-send-email-fweisbec@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1308870760-14153-1-git-send-email-fweisbec@gmail.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 24, 2011 at 01:12:37AM +0200, Frederic Weisbecker wrote: > This time I have no current practical cases to fix. Those I fixed > in previous versions were actually using rcu_dereference_raw(), which > is legal in extended qs. > > Frederic Weisbecker (3): > rcu: Detect illegal rcu dereference in extended quiescent state > rcu: Inform the user about dynticks idle mode on PROVE_RCU warning > rcu: Warn when rcu_read_lock() is used in extended quiescent state > > include/linux/rcupdate.h | 68 +++++++++++++++++++++++++++++++++++++++------- > kernel/lockdep.c | 4 +++ > kernel/rcupdate.c | 4 +++ > kernel/rcutiny.c | 13 +++++++++ > kernel/rcutree.c | 14 +++++++++ > 5 files changed, 93 insertions(+), 10 deletions(-) Queued, thank you, Frederic! I have also applied your approach to SRCU, and I applied the following to simplify the code a bit -- please let me know if there are any problems with this approach. Thanx, Paul ------------------------------------------------------------------------ rcu: Remove one layer of abstraction from PROVE_RCU checking Simplify things a bit by substituting the definitions of the single-line rcu_read_acquire(), rcu_read_release(), rcu_read_acquire_bh(), rcu_read_release_bh(), rcu_read_acquire_sched(), and rcu_read_release_sched() functions at their call points. Signed-off-by: Paul E. McKenney diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 16717c3..7b0cdf4 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -264,41 +264,8 @@ static inline void rcu_lock_release(struct lockdep_map *map) } extern struct lockdep_map rcu_lock_map; - -static inline void rcu_read_acquire(void) -{ - rcu_lock_acquire(&rcu_lock_map); -} - -static inline void rcu_read_release(void) -{ - rcu_lock_release(&rcu_lock_map); -} - extern struct lockdep_map rcu_bh_lock_map; - -static inline void rcu_read_acquire_bh(void) -{ - rcu_lock_acquire(&rcu_bh_lock_map); -} - -static inline void rcu_read_release_bh(void) -{ - rcu_lock_release(&rcu_bh_lock_map); -} - extern struct lockdep_map rcu_sched_lock_map; - -static inline void rcu_read_acquire_sched(void) -{ - rcu_lock_acquire(&rcu_sched_lock_map); -} - -static inline void rcu_read_release_sched(void) -{ - rcu_lock_release(&rcu_sched_lock_map); -} - extern int debug_lockdep_rcu_enabled(void); /** @@ -369,12 +336,8 @@ static inline int rcu_read_lock_sched_held(void) #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ -# define rcu_read_acquire() do { } while (0) -# define rcu_read_release() do { } while (0) -# define rcu_read_acquire_bh() do { } while (0) -# define rcu_read_release_bh() do { } while (0) -# define rcu_read_acquire_sched() do { } while (0) -# define rcu_read_release_sched() do { } while (0) +# define rcu_lock_acquire(a) do { } while (0) +# define rcu_lock_release(a) do { } while (0) static inline int rcu_read_lock_held(void) { @@ -717,7 +680,7 @@ static inline void rcu_read_lock(void) { __rcu_read_lock(); __acquire(RCU); - rcu_read_acquire(); + rcu_lock_acquire(&rcu_lock_map); } /* @@ -737,7 +700,7 @@ static inline void rcu_read_lock(void) */ static inline void rcu_read_unlock(void) { - rcu_read_release(); + rcu_lock_release(&rcu_lock_map); __release(RCU); __rcu_read_unlock(); } @@ -758,7 +721,7 @@ static inline void rcu_read_lock_bh(void) { __rcu_read_lock_bh(); __acquire(RCU_BH); - rcu_read_acquire_bh(); + rcu_lock_acquire(&rcu_bh_lock_map); } /* @@ -768,7 +731,7 @@ static inline void rcu_read_lock_bh(void) */ static inline void rcu_read_unlock_bh(void) { - rcu_read_release_bh(); + rcu_lock_release(&rcu_bh_lock_map); __release(RCU_BH); __rcu_read_unlock_bh(); } @@ -785,7 +748,7 @@ static inline void rcu_read_lock_sched(void) { preempt_disable(); __acquire(RCU_SCHED); - rcu_read_acquire_sched(); + rcu_lock_acquire(&rcu_sched_lock_map); } /* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */ @@ -802,7 +765,7 @@ static inline notrace void rcu_read_lock_sched_notrace(void) */ static inline void rcu_read_unlock_sched(void) { - rcu_read_release_sched(); + rcu_lock_release(&rcu_sched_lock_map); __release(RCU_SCHED); preempt_enable(); }