1#ifndef QEMU_RCU_H
2#define QEMU_RCU_H
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27#include "qemu/thread.h"
28#include "qemu/queue.h"
29#include "qemu/atomic.h"
30
31#ifdef __cplusplus
32extern "C" {
33#endif
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42
43#ifdef DEBUG_RCU
44#define rcu_assert(args...) assert(args)
45#else
46#define rcu_assert(args...)
47#endif
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53
54extern unsigned long rcu_gp_ctr;
55
56extern QemuEvent rcu_gp_event;
57
58struct rcu_reader_data {
59
60 unsigned long ctr;
61 bool waiting;
62
63
64 unsigned depth;
65
66
67 QLIST_ENTRY(rcu_reader_data) node;
68};
69
70extern __thread struct rcu_reader_data rcu_reader;
71
72static inline void rcu_read_lock(void)
73{
74 struct rcu_reader_data *p_rcu_reader = &rcu_reader;
75 unsigned ctr;
76
77 if (p_rcu_reader->depth++ > 0) {
78 return;
79 }
80
81 ctr = atomic_read(&rcu_gp_ctr);
82 atomic_xchg(&p_rcu_reader->ctr, ctr);
83}
84
85static inline void rcu_read_unlock(void)
86{
87 struct rcu_reader_data *p_rcu_reader = &rcu_reader;
88
89 assert(p_rcu_reader->depth != 0);
90 if (--p_rcu_reader->depth > 0) {
91 return;
92 }
93
94 atomic_xchg(&p_rcu_reader->ctr, 0);
95 if (unlikely(atomic_read(&p_rcu_reader->waiting))) {
96 atomic_set(&p_rcu_reader->waiting, false);
97 qemu_event_set(&rcu_gp_event);
98 }
99}
100
101extern void synchronize_rcu(void);
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106extern void rcu_register_thread(void);
107extern void rcu_unregister_thread(void);
108extern void rcu_after_fork(void);
109
110struct rcu_head;
111typedef void RCUCBFunc(struct rcu_head *head);
112
113struct rcu_head {
114 struct rcu_head *next;
115 RCUCBFunc *func;
116};
117
118extern void call_rcu1(struct rcu_head *head, RCUCBFunc *func);
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122
123#define call_rcu(head, func, field) \
124 call_rcu1(({ \
125 char __attribute__((unused)) \
126 offset_must_be_zero[-offsetof(typeof(*(head)), field)], \
127 func_type_invalid = (func) - (void (*)(typeof(head)))(func); \
128 &(head)->field; \
129 }), \
130 (RCUCBFunc *)(func))
131
132#define g_free_rcu(obj, field) \
133 call_rcu1(({ \
134 char __attribute__((unused)) \
135 offset_must_be_zero[-offsetof(typeof(*(obj)), field)]; \
136 &(obj)->field; \
137 }), \
138 (RCUCBFunc *)g_free);
139
140#ifdef __cplusplus
141}
142#endif
143
144#endif
145