diff options
Diffstat (limited to 'ANDROID_3.4.5/include/linux/srcu.h')
| -rw-r--r-- | ANDROID_3.4.5/include/linux/srcu.h | 239 |
1 files changed, 0 insertions, 239 deletions
diff --git a/ANDROID_3.4.5/include/linux/srcu.h b/ANDROID_3.4.5/include/linux/srcu.h deleted file mode 100644 index d3d5fa54..00000000 --- a/ANDROID_3.4.5/include/linux/srcu.h +++ /dev/null @@ -1,239 +0,0 @@ -/* - * Sleepable 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 (C) IBM Corporation, 2006 - * - * Author: Paul McKenney <paulmck@us.ibm.com> - * - * For detailed explanation of Read-Copy Update mechanism see - - * Documentation/RCU/ *.txt - * - */ - -#ifndef _LINUX_SRCU_H -#define _LINUX_SRCU_H - -#include <linux/mutex.h> -#include <linux/rcupdate.h> - -struct srcu_struct_array { - int c[2]; -}; - -struct srcu_struct { - int completed; - struct srcu_struct_array __percpu *per_cpu_ref; - struct mutex mutex; -#ifdef CONFIG_DEBUG_LOCK_ALLOC - struct lockdep_map dep_map; -#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ -}; - -#ifndef CONFIG_PREEMPT -#define srcu_barrier() barrier() -#else /* #ifndef CONFIG_PREEMPT */ -#define srcu_barrier() -#endif /* #else #ifndef CONFIG_PREEMPT */ - -#ifdef CONFIG_DEBUG_LOCK_ALLOC - -int __init_srcu_struct(struct srcu_struct *sp, const char *name, - struct lock_class_key *key); - -#define init_srcu_struct(sp) \ -({ \ - static struct lock_class_key __srcu_key; \ - \ - __init_srcu_struct((sp), #sp, &__srcu_key); \ -}) - -#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ - -int init_srcu_struct(struct srcu_struct *sp); - -#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ - -void cleanup_srcu_struct(struct srcu_struct *sp); -int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp); -void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp); -void synchronize_srcu(struct srcu_struct *sp); -void synchronize_srcu_expedited(struct srcu_struct *sp); -long srcu_batches_completed(struct srcu_struct *sp); - -#ifdef CONFIG_DEBUG_LOCK_ALLOC - -/** - * srcu_read_lock_held - might we be in SRCU read-side critical section? - * - * If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an SRCU - * read-side critical section. In absence of CONFIG_DEBUG_LOCK_ALLOC, - * this assumes we are in an SRCU read-side critical section unless it can - * prove otherwise. - * - * Checks debug_lockdep_rcu_enabled() to prevent false positives during boot - * and while lockdep is disabled. - * - * Note that if the CPU is in the idle loop from an RCU point of view - * (ie: that we are in the section between rcu_idle_enter() and - * rcu_idle_exit()) then srcu_read_lock_held() returns false even if - * the CPU did an srcu_read_lock(). The reason for this is that RCU - * ignores CPUs that are in such a section, considering these as in - * extended quiescent state, so such a CPU is effectively never in an - * RCU read-side critical section regardless of what RCU primitives it - * invokes. This state of affairs is required --- we need to keep an - * RCU-free window in idle where the CPU may possibly enter into low - * power mode. This way we can notice an extended quiescent state to - * other CPUs that started a grace period. Otherwise we would delay any - * grace period as long as we run in the idle task. - * - * Similarly, we avoid claiming an SRCU read lock held if the current - * CPU is offline. - */ -static inline int srcu_read_lock_held(struct srcu_struct *sp) -{ - if (!debug_lockdep_rcu_enabled()) - return 1; - if (rcu_is_cpu_idle()) - return 0; - if (!rcu_lockdep_current_cpu_online()) - return 0; - return lock_is_held(&sp->dep_map); -} - -#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ - -static inline int srcu_read_lock_held(struct srcu_struct *sp) -{ - return 1; -} - -#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ - -/** - * srcu_dereference_check - fetch SRCU-protected pointer for later dereferencing - * @p: the pointer to fetch and protect for later dereferencing - * @sp: pointer to the srcu_struct, which is used to check that we - * really are in an SRCU read-side critical section. - * @c: condition to check for update-side use - * - * If PROVE_RCU is enabled, invoking this outside of an RCU read-side - * critical section will result in an RCU-lockdep splat, unless @c evaluates - * to 1. The @c argument will normally be a logical expression containing - * lockdep_is_held() calls. - */ -#define srcu_dereference_check(p, sp, c) \ - __rcu_dereference_check((p), srcu_read_lock_held(sp) || (c), __rcu) - -/** - * srcu_dereference - fetch SRCU-protected pointer for later dereferencing - * @p: the pointer to fetch and protect for later dereferencing - * @sp: pointer to the srcu_struct, which is used to check that we - * really are in an SRCU read-side critical section. - * - * Makes rcu_dereference_check() do the dirty work. If PROVE_RCU - * is enabled, invoking this outside of an RCU read-side critical - * section will result in an RCU-lockdep splat. - */ -#define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0) - -/** - * srcu_read_lock - register a new reader for an SRCU-protected structure. - * @sp: srcu_struct in which to register the new reader. - * - * Enter an SRCU read-side critical section. Note that SRCU read-side - * critical sections may be nested. However, it is illegal to - * call anything that waits on an SRCU grace period for the same - * srcu_struct, whether directly or indirectly. Please note that - * one way to indirectly wait on an SRCU grace period is to acquire - * a mutex that is held elsewhere while calling synchronize_srcu() or - * synchronize_srcu_expedited(). - * - * Note that srcu_read_lock() and the matching srcu_read_unlock() must - * occur in the same context, for example, it is illegal to invoke - * srcu_read_unlock() in an irq handler if the matching srcu_read_lock() - * was invoked in process context. - */ -static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp) -{ - int retval = __srcu_read_lock(sp); - - rcu_lock_acquire(&(sp)->dep_map); - rcu_lockdep_assert(!rcu_is_cpu_idle(), - "srcu_read_lock() used illegally while idle"); - return retval; -} - -/** - * srcu_read_unlock - unregister a old reader from an SRCU-protected structure. - * @sp: srcu_struct in which to unregister the old reader. - * @idx: return value from corresponding srcu_read_lock(). - * - * Exit an SRCU read-side critical section. - */ -static inline void srcu_read_unlock(struct srcu_struct *sp, int idx) - __releases(sp) -{ - rcu_lockdep_assert(!rcu_is_cpu_idle(), - "srcu_read_unlock() used illegally while idle"); - rcu_lock_release(&(sp)->dep_map); - __srcu_read_unlock(sp, idx); -} - -/** - * srcu_read_lock_raw - register a new reader for an SRCU-protected structure. - * @sp: srcu_struct in which to register the new reader. - * - * Enter an SRCU read-side critical section. Similar to srcu_read_lock(), - * but avoids the RCU-lockdep checking. This means that it is legal to - * use srcu_read_lock_raw() in one context, for example, in an exception - * handler, and then have the matching srcu_read_unlock_raw() in another - * context, for example in the task that took the exception. - * - * However, the entire SRCU read-side critical section must reside within a - * single task. For example, beware of using srcu_read_lock_raw() in - * a device interrupt handler and srcu_read_unlock() in the interrupted - * task: This will not work if interrupts are threaded. - */ -static inline int srcu_read_lock_raw(struct srcu_struct *sp) -{ - unsigned long flags; - int ret; - - local_irq_save(flags); - ret = __srcu_read_lock(sp); - local_irq_restore(flags); - return ret; -} - -/** - * srcu_read_unlock_raw - unregister reader from an SRCU-protected structure. - * @sp: srcu_struct in which to unregister the old reader. - * @idx: return value from corresponding srcu_read_lock_raw(). - * - * Exit an SRCU read-side critical section without lockdep-RCU checking. - * See srcu_read_lock_raw() for more details. - */ -static inline void srcu_read_unlock_raw(struct srcu_struct *sp, int idx) -{ - unsigned long flags; - - local_irq_save(flags); - __srcu_read_unlock(sp, idx); - local_irq_restore(flags); -} - -#endif |