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a66e0092 | 1 | /* SPDX-License-Identifier: GPL-2.0+ */ |
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2 | /* |
3 | * RCU-based infrastructure for lightweight reader-writer locking | |
4 | * | |
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5 | * Copyright (c) 2015, Red Hat, Inc. |
6 | * | |
7 | * Author: Oleg Nesterov <oleg@redhat.com> | |
8 | */ | |
9 | ||
10 | #ifndef _LINUX_RCU_SYNC_H_ | |
11 | #define _LINUX_RCU_SYNC_H_ | |
12 | ||
13 | #include <linux/wait.h> | |
14 | #include <linux/rcupdate.h> | |
15 | ||
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16 | enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC }; |
17 | ||
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18 | /* Structure to mediate between updaters and fastpath-using readers. */ |
19 | struct rcu_sync { | |
20 | int gp_state; | |
21 | int gp_count; | |
22 | wait_queue_head_t gp_wait; | |
23 | ||
24 | int cb_state; | |
25 | struct rcu_head cb_head; | |
26 | ||
82e8c565 | 27 | enum rcu_sync_type gp_type; |
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28 | }; |
29 | ||
4bace734 | 30 | extern void rcu_sync_lockdep_assert(struct rcu_sync *); |
3a518b76 | 31 | |
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32 | /** |
33 | * rcu_sync_is_idle() - Are readers permitted to use their fastpaths? | |
34 | * @rsp: Pointer to rcu_sync structure to use for synchronization | |
35 | * | |
36 | * Returns true if readers are permitted to use their fastpaths. | |
37 | * Must be invoked within an RCU read-side critical section whose | |
38 | * flavor matches that of the rcu_sync struture. | |
39 | */ | |
40 | static inline bool rcu_sync_is_idle(struct rcu_sync *rsp) | |
41 | { | |
3a518b76 | 42 | #ifdef CONFIG_PROVE_RCU |
4bace734 | 43 | rcu_sync_lockdep_assert(rsp); |
3a518b76 | 44 | #endif |
4bace734 | 45 | return !rsp->gp_state; /* GP_IDLE */ |
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46 | } |
47 | ||
cc44ca84 | 48 | extern void rcu_sync_init(struct rcu_sync *, enum rcu_sync_type); |
3942a9bd | 49 | extern void rcu_sync_enter_start(struct rcu_sync *); |
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50 | extern void rcu_sync_enter(struct rcu_sync *); |
51 | extern void rcu_sync_exit(struct rcu_sync *); | |
07899a6e | 52 | extern void rcu_sync_dtor(struct rcu_sync *); |
cc44ca84 | 53 | |
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54 | #define __RCU_SYNC_INITIALIZER(name, type) { \ |
55 | .gp_state = 0, \ | |
56 | .gp_count = 0, \ | |
57 | .gp_wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.gp_wait), \ | |
58 | .cb_state = 0, \ | |
59 | .gp_type = type, \ | |
60 | } | |
61 | ||
62 | #define __DEFINE_RCU_SYNC(name, type) \ | |
63 | struct rcu_sync_struct name = __RCU_SYNC_INITIALIZER(name, type) | |
64 | ||
65 | #define DEFINE_RCU_SYNC(name) \ | |
66 | __DEFINE_RCU_SYNC(name, RCU_SYNC) | |
67 | ||
68 | #define DEFINE_RCU_SCHED_SYNC(name) \ | |
69 | __DEFINE_RCU_SYNC(name, RCU_SCHED_SYNC) | |
70 | ||
71 | #define DEFINE_RCU_BH_SYNC(name) \ | |
72 | __DEFINE_RCU_SYNC(name, RCU_BH_SYNC) | |
73 | ||
cc44ca84 | 74 | #endif /* _LINUX_RCU_SYNC_H_ */ |