1 /*
2 * Read-Copy Update definitions shared among RCU implementations.
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, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright IBM Corporation, 2011
19 *
20 * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
21 */
22
23 #ifndef __LINUX_RCU_H
24 #define __LINUX_RCU_H
25
26 #ifdef CONFIG_RCU_TRACE
27 #define RCU_TRACE(stmt) stmt
28 #else /* #ifdef CONFIG_RCU_TRACE */
29 #define RCU_TRACE(stmt)
30 #endif /* #else #ifdef CONFIG_RCU_TRACE */
31
32 /*
33 * Process-level increment to ->dynticks_nesting field. This allows for
34 * architectures that use half-interrupts and half-exceptions from
35 * process context.
36 */
37 #define DYNTICK_TASK_NESTING (LLONG_MAX / 2 - 1)
38
39 /*
40 * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
41 * by call_rcu() and rcu callback execution, and are therefore not part of the
42 * RCU API. Leaving in rcupdate.h because they are used by all RCU flavors.
43 */
44
45 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
46 # define STATE_RCU_HEAD_READY 0
47 # define STATE_RCU_HEAD_QUEUED 1
48
49 extern struct debug_obj_descr rcuhead_debug_descr;
50
debug_rcu_head_queue(struct rcu_head * head)51 static inline void debug_rcu_head_queue(struct rcu_head *head)
52 {
53 WARN_ON_ONCE((unsigned long)head & 0x3);
54 debug_object_activate(head, &rcuhead_debug_descr);
55 debug_object_active_state(head, &rcuhead_debug_descr,
56 STATE_RCU_HEAD_READY,
57 STATE_RCU_HEAD_QUEUED);
58 }
59
debug_rcu_head_unqueue(struct rcu_head * head)60 static inline void debug_rcu_head_unqueue(struct rcu_head *head)
61 {
62 debug_object_active_state(head, &rcuhead_debug_descr,
63 STATE_RCU_HEAD_QUEUED,
64 STATE_RCU_HEAD_READY);
65 debug_object_deactivate(head, &rcuhead_debug_descr);
66 }
67 #else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
debug_rcu_head_queue(struct rcu_head * head)68 static inline void debug_rcu_head_queue(struct rcu_head *head)
69 {
70 }
71
debug_rcu_head_unqueue(struct rcu_head * head)72 static inline void debug_rcu_head_unqueue(struct rcu_head *head)
73 {
74 }
75 #endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
76
77 extern void kfree(const void *);
78
__rcu_reclaim(char * rn,struct rcu_head * head)79 static inline void __rcu_reclaim(char *rn, struct rcu_head *head)
80 {
81 unsigned long offset = (unsigned long)head->func;
82
83 if (__is_kfree_rcu_offset(offset)) {
84 RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset));
85 kfree((void *)head - offset);
86 } else {
87 RCU_TRACE(trace_rcu_invoke_callback(rn, head));
88 head->func(head);
89 }
90 }
91
92 #endif /* __LINUX_RCU_H */
93