1 /* 2 * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, you can access it online at 16 * http://www.gnu.org/licenses/gpl-2.0.html. 17 * 18 * Copyright IBM Corporation, 2008 19 * 20 * Author: Paul E. McKenney <[email protected]> 21 * 22 * For detailed explanation of Read-Copy Update mechanism see - 23 * Documentation/RCU 24 */ 25 #ifndef __LINUX_TINY_H 26 #define __LINUX_TINY_H 27 28 #include <linux/cache.h> 29 30 static inline unsigned long get_state_synchronize_rcu(void) 31 { 32 return 0; 33 } 34 35 static inline void cond_synchronize_rcu(unsigned long oldstate) 36 { 37 might_sleep(); 38 } 39 40 static inline void rcu_barrier_bh(void) 41 { 42 wait_rcu_gp(call_rcu_bh); 43 } 44 45 static inline void rcu_barrier_sched(void) 46 { 47 wait_rcu_gp(call_rcu_sched); 48 } 49 50 static inline void synchronize_rcu_expedited(void) 51 { 52 synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */ 53 } 54 55 static inline void rcu_barrier(void) 56 { 57 rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */ 58 } 59 60 static inline void synchronize_rcu_bh(void) 61 { 62 synchronize_sched(); 63 } 64 65 static inline void synchronize_rcu_bh_expedited(void) 66 { 67 synchronize_sched(); 68 } 69 70 static inline void synchronize_sched_expedited(void) 71 { 72 synchronize_sched(); 73 } 74 75 static inline void kfree_call_rcu(struct rcu_head *head, 76 void (*func)(struct rcu_head *rcu)) 77 { 78 call_rcu(head, func); 79 } 80 81 static inline void rcu_note_context_switch(int cpu) 82 { 83 rcu_sched_qs(cpu); 84 } 85 86 /* 87 * Take advantage of the fact that there is only one CPU, which 88 * allows us to ignore virtualization-based context switches. 89 */ 90 static inline void rcu_virt_note_context_switch(int cpu) 91 { 92 } 93 94 /* 95 * Return the number of grace periods. 96 */ 97 static inline long rcu_batches_completed(void) 98 { 99 return 0; 100 } 101 102 /* 103 * Return the number of bottom-half grace periods. 104 */ 105 static inline long rcu_batches_completed_bh(void) 106 { 107 return 0; 108 } 109 110 static inline void rcu_force_quiescent_state(void) 111 { 112 } 113 114 static inline void rcu_bh_force_quiescent_state(void) 115 { 116 } 117 118 static inline void rcu_sched_force_quiescent_state(void) 119 { 120 } 121 122 static inline void rcu_cpu_stall_reset(void) 123 { 124 } 125 126 static inline void exit_rcu(void) 127 { 128 } 129 130 #ifdef CONFIG_DEBUG_LOCK_ALLOC 131 extern int rcu_scheduler_active __read_mostly; 132 void rcu_scheduler_starting(void); 133 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ 134 static inline void rcu_scheduler_starting(void) 135 { 136 } 137 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ 138 139 #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) 140 141 static inline bool rcu_is_watching(void) 142 { 143 return __rcu_is_watching(); 144 } 145 146 #else /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */ 147 148 static inline bool rcu_is_watching(void) 149 { 150 return true; 151 } 152 153 154 #endif /* #else defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */ 155 156 #endif /* __LINUX_RCUTINY_H */ 157