Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757568Ab0BLABR (ORCPT ); Thu, 11 Feb 2010 19:01:17 -0500 Received: from e6.ny.us.ibm.com ([32.97.182.146]:47919 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757504Ab0BLABH (ORCPT ); Thu, 11 Feb 2010 19:01:07 -0500 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 02/13] rcu: add lockdep-enabled variants of rcu_dereference() Date: Thu, 11 Feb 2010 16:00:28 -0800 Message-Id: <1265932839-25899-2-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.6.6 In-Reply-To: <20100212000016.GA25781@linux.vnet.ibm.com> References: <20100212000016.GA25781@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3911 Lines: 113 Make rcu_dereference() check for being in an RCU read-side critical section, and create rcu_dereference_bh(), rcu_dereference_sched(), and srcu_dereference() to check for the other flavors of RCU. Also create rcu_dereference_raw() to avoid checking, and make rcu_dereference_check() use rcu_dereference_raw(). Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 41 ++++++++++++++++++++++++++++++++++------- include/linux/srcu.h | 8 ++++++++ 2 files changed, 42 insertions(+), 7 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index e3d37ef..839d296 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -184,12 +184,12 @@ static inline int rcu_read_lock_sched_held(void) ({ \ if (debug_locks) \ WARN_ON_ONCE(!(c)); \ - rcu_dereference(p); \ + rcu_dereference_raw(p); \ }) #else /* #ifdef CONFIG_PROVE_RCU */ -#define rcu_dereference_check(p, c) rcu_dereference(p) +#define rcu_dereference_check(p, c) rcu_dereference_raw(p) #endif /* #else #ifdef CONFIG_PROVE_RCU */ @@ -325,22 +325,49 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) /** - * rcu_dereference - fetch an RCU-protected pointer in an - * RCU read-side critical section. This pointer may later - * be safely dereferenced. + * rcu_dereference_raw - fetch an RCU-protected pointer + * + * The caller must be within some flavor of RCU read-side critical + * section, or must be otherwise preventing the pointer from changing, + * for example, by holding an appropriate lock. This pointer may later + * be safely dereferenced. It is the caller's responsibility to have + * done the right thing, as this primitive does no checking of any kind. * * Inserts memory barriers on architectures that require them * (currently only the Alpha), and, more importantly, documents * exactly which pointers are protected by RCU. */ - -#define rcu_dereference(p) ({ \ +#define rcu_dereference_raw(p) ({ \ typeof(p) _________p1 = ACCESS_ONCE(p); \ smp_read_barrier_depends(); \ (_________p1); \ }) /** + * rcu_dereference - fetch an RCU-protected pointer, checking for RCU + * + * Makes rcu_dereference_check() do the dirty work. + */ +#define rcu_dereference(p) \ + rcu_dereference_check(p, rcu_read_lock_held()) + +/** + * rcu_dereference_bh - fetch an RCU-protected pointer, checking for RCU-bh + * + * Makes rcu_dereference_check() do the dirty work. + */ +#define rcu_dereference_bh(p) \ + rcu_dereference_check(p, rcu_read_lock_bh_held()) + +/** + * rcu_dereference_sched - fetch RCU-protected pointer, checking for RCU-sched + * + * Makes rcu_dereference_check() do the dirty work. + */ +#define rcu_dereference_sched(p) \ + rcu_dereference_check(p, rcu_read_lock_sched_held()) + +/** * rcu_assign_pointer - assign (publicize) a pointer to a newly * initialized structure that will be dereferenced by RCU read-side * critical sections. Returns the value assigned. diff --git a/include/linux/srcu.h b/include/linux/srcu.h index adbe167..3084f80 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -106,6 +106,14 @@ static inline int srcu_read_lock_held(struct srcu_struct *sp) #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ /** + * srcu_dereference - fetch SRCU-protected pointer with checking + * + * Makes rcu_dereference_check() do the dirty work. + */ +#define srcu_dereference(p, sp) \ + rcu_dereference_check(p, srcu_read_lock_held(sp)) + +/** * srcu_read_lock - register a new reader for an SRCU-protected structure. * @sp: srcu_struct in which to register the new reader. * -- 1.6.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/