| /* |
| * Read-Copy Update mechanism for mutual exclusion |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| * |
| * Copyright IBM Corporation, 2001 |
| * |
| * Authors: Dipankar Sarma <dipankar@in.ibm.com> |
| * Manfred Spraul <manfred@colorfullife.com> |
| * |
| * Based on the original work by Paul McKenney <paulmck@us.ibm.com> |
| * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen. |
| * Papers: |
| * http://www.rdrop.com/users/paulmck/paper/rclockpdcsproof.pdf |
| * http://lse.sourceforge.net/locking/rclock_OLS.2001.05.01c.sc.pdf (OLS2001) |
| * |
| * For detailed explanation of Read-Copy Update mechanism see - |
| * http://lse.sourceforge.net/locking/rcupdate.html |
| * |
| */ |
| #include <linux/types.h> |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/spinlock.h> |
| #include <linux/smp.h> |
| #include <linux/interrupt.h> |
| #include <linux/sched.h> |
| #include <asm/atomic.h> |
| #include <linux/bitops.h> |
| #include <linux/percpu.h> |
| #include <linux/notifier.h> |
| #include <linux/cpu.h> |
| #include <linux/mutex.h> |
| #include <linux/module.h> |
| #include <linux/hardirq.h> |
| |
| #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| static struct lock_class_key rcu_lock_key; |
| struct lockdep_map rcu_lock_map = |
| STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key); |
| EXPORT_SYMBOL_GPL(rcu_lock_map); |
| |
| static struct lock_class_key rcu_bh_lock_key; |
| struct lockdep_map rcu_bh_lock_map = |
| STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_bh", &rcu_bh_lock_key); |
| EXPORT_SYMBOL_GPL(rcu_bh_lock_map); |
| |
| static struct lock_class_key rcu_sched_lock_key; |
| struct lockdep_map rcu_sched_lock_map = |
| STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_sched", &rcu_sched_lock_key); |
| EXPORT_SYMBOL_GPL(rcu_sched_lock_map); |
| #endif |
| |
| #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| |
| int debug_lockdep_rcu_enabled(void) |
| { |
| return rcu_scheduler_active && debug_locks && |
| current->lockdep_recursion == 0; |
| } |
| EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled); |
| |
| /** |
| * rcu_read_lock_bh_held - might we be in RCU-bh read-side critical section? |
| * |
| * Check for bottom half being disabled, which covers both the |
| * CONFIG_PROVE_RCU and not cases. Note that if someone uses |
| * rcu_read_lock_bh(), but then later enables BH, lockdep (if enabled) |
| * will show the situation. |
| * |
| * Check debug_lockdep_rcu_enabled() to prevent false positives during boot. |
| */ |
| int rcu_read_lock_bh_held(void) |
| { |
| if (!debug_lockdep_rcu_enabled()) |
| return 1; |
| return in_softirq(); |
| } |
| EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held); |
| |
| #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ |
| |
| /* |
| * Awaken the corresponding synchronize_rcu() instance now that a |
| * grace period has elapsed. |
| */ |
| void wakeme_after_rcu(struct rcu_head *head) |
| { |
| struct rcu_synchronize *rcu; |
| |
| rcu = container_of(head, struct rcu_synchronize, head); |
| complete(&rcu->completion); |
| } |
| |
| #ifdef CONFIG_PROVE_RCU |
| /* |
| * wrapper function to avoid #include problems. |
| */ |
| int rcu_my_thread_group_empty(void) |
| { |
| return thread_group_empty(current); |
| } |
| EXPORT_SYMBOL_GPL(rcu_my_thread_group_empty); |
| #endif /* #ifdef CONFIG_PROVE_RCU */ |