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#include "qemu/notify.h"
31#include "qemu/sys_membarrier.h"
32
33#ifdef __cplusplus
34extern "C" {
35#endif
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44
45#ifdef DEBUG_RCU
46#define rcu_assert(args...) assert(args)
47#else
48#define rcu_assert(args...)
49#endif
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54
55
56extern unsigned long rcu_gp_ctr;
57
58extern QemuEvent rcu_gp_event;
59
60struct rcu_reader_data {
61
62 unsigned long ctr;
63 bool waiting;
64
65
66 unsigned depth;
67
68
69 QLIST_ENTRY(rcu_reader_data) node;
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75
76 NotifierList force_rcu;
77};
78
79extern __thread struct rcu_reader_data rcu_reader;
80
81static inline void rcu_read_lock(void)
82{
83 struct rcu_reader_data *p_rcu_reader = &rcu_reader;
84 unsigned ctr;
85
86 if (p_rcu_reader->depth++ > 0) {
87 return;
88 }
89
90 ctr = qatomic_read(&rcu_gp_ctr);
91 qatomic_set(&p_rcu_reader->ctr, ctr);
92
93
94 smp_mb_placeholder();
95}
96
97static inline void rcu_read_unlock(void)
98{
99 struct rcu_reader_data *p_rcu_reader = &rcu_reader;
100
101 assert(p_rcu_reader->depth != 0);
102 if (--p_rcu_reader->depth > 0) {
103 return;
104 }
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111 qatomic_store_release(&p_rcu_reader->ctr, 0);
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113
114 smp_mb_placeholder();
115 if (unlikely(qatomic_read(&p_rcu_reader->waiting))) {
116 qatomic_set(&p_rcu_reader->waiting, false);
117 qemu_event_set(&rcu_gp_event);
118 }
119}
120
121extern void synchronize_rcu(void);
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125
126extern void rcu_register_thread(void);
127extern void rcu_unregister_thread(void);
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131
132extern void rcu_enable_atfork(void);
133extern void rcu_disable_atfork(void);
134
135struct rcu_head;
136typedef void RCUCBFunc(struct rcu_head *head);
137
138struct rcu_head {
139 struct rcu_head *next;
140 RCUCBFunc *func;
141};
142
143extern void call_rcu1(struct rcu_head *head, RCUCBFunc *func);
144extern void drain_call_rcu(void);
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148
149#define call_rcu(head, func, field) \
150 call_rcu1(({ \
151 char __attribute__((unused)) \
152 offset_must_be_zero[-offsetof(typeof(*(head)), field)], \
153 func_type_invalid = (func) - (void (*)(typeof(head)))(func); \
154 &(head)->field; \
155 }), \
156 (RCUCBFunc *)(func))
157
158#define g_free_rcu(obj, field) \
159 call_rcu1(({ \
160 char __attribute__((unused)) \
161 offset_must_be_zero[-offsetof(typeof(*(obj)), field)]; \
162 &(obj)->field; \
163 }), \
164 (RCUCBFunc *)g_free);
165
166typedef void RCUReadAuto;
167static inline RCUReadAuto *rcu_read_auto_lock(void)
168{
169 rcu_read_lock();
170
171 return (void *)(uintptr_t)0x1;
172}
173
174static inline void rcu_read_auto_unlock(RCUReadAuto *r)
175{
176 rcu_read_unlock();
177}
178
179G_DEFINE_AUTOPTR_CLEANUP_FUNC(RCUReadAuto, rcu_read_auto_unlock)
180
181#define WITH_RCU_READ_LOCK_GUARD() \
182 WITH_RCU_READ_LOCK_GUARD_(glue(_rcu_read_auto, __COUNTER__))
183
184#define WITH_RCU_READ_LOCK_GUARD_(var) \
185 for (g_autoptr(RCUReadAuto) var = rcu_read_auto_lock(); \
186 (var); rcu_read_auto_unlock(var), (var) = NULL)
187
188#define RCU_READ_LOCK_GUARD() \
189 g_autoptr(RCUReadAuto) _rcu_read_auto __attribute__((unused)) = rcu_read_auto_lock()
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194
195void rcu_add_force_rcu_notifier(Notifier *n);
196void rcu_remove_force_rcu_notifier(Notifier *n);
197
198#ifdef __cplusplus
199}
200#endif
201
202#endif
203