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1 | /* |
2 | * RCU-based infrastructure for lightweight reader-writer locking | |
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 (c) 2015, Red Hat, Inc. | |
19 | * | |
20 | * Author: Oleg Nesterov <oleg@redhat.com> | |
21 | */ | |
22 | ||
23 | #ifndef _LINUX_RCU_SYNC_H_ | |
24 | #define _LINUX_RCU_SYNC_H_ | |
25 | ||
26 | #include <linux/wait.h> | |
27 | #include <linux/rcupdate.h> | |
28 | ||
82e8c565 ON |
29 | enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC }; |
30 | ||
cc44ca84 ON |
31 | /* Structure to mediate between updaters and fastpath-using readers. */ |
32 | struct rcu_sync { | |
33 | int gp_state; | |
34 | int gp_count; | |
35 | wait_queue_head_t gp_wait; | |
36 | ||
37 | int cb_state; | |
38 | struct rcu_head cb_head; | |
39 | ||
82e8c565 | 40 | enum rcu_sync_type gp_type; |
cc44ca84 ON |
41 | }; |
42 | ||
4bace734 | 43 | extern void rcu_sync_lockdep_assert(struct rcu_sync *); |
3a518b76 | 44 | |
cc44ca84 ON |
45 | /** |
46 | * rcu_sync_is_idle() - Are readers permitted to use their fastpaths? | |
47 | * @rsp: Pointer to rcu_sync structure to use for synchronization | |
48 | * | |
49 | * Returns true if readers are permitted to use their fastpaths. | |
50 | * Must be invoked within an RCU read-side critical section whose | |
51 | * flavor matches that of the rcu_sync struture. | |
52 | */ | |
53 | static inline bool rcu_sync_is_idle(struct rcu_sync *rsp) | |
54 | { | |
3a518b76 | 55 | #ifdef CONFIG_PROVE_RCU |
4bace734 | 56 | rcu_sync_lockdep_assert(rsp); |
3a518b76 | 57 | #endif |
4bace734 | 58 | return !rsp->gp_state; /* GP_IDLE */ |
cc44ca84 ON |
59 | } |
60 | ||
cc44ca84 ON |
61 | extern void rcu_sync_init(struct rcu_sync *, enum rcu_sync_type); |
62 | extern void rcu_sync_enter(struct rcu_sync *); | |
63 | extern void rcu_sync_exit(struct rcu_sync *); | |
07899a6e | 64 | extern void rcu_sync_dtor(struct rcu_sync *); |
cc44ca84 | 65 | |
82e8c565 ON |
66 | #define __RCU_SYNC_INITIALIZER(name, type) { \ |
67 | .gp_state = 0, \ | |
68 | .gp_count = 0, \ | |
69 | .gp_wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.gp_wait), \ | |
70 | .cb_state = 0, \ | |
71 | .gp_type = type, \ | |
72 | } | |
73 | ||
74 | #define __DEFINE_RCU_SYNC(name, type) \ | |
75 | struct rcu_sync_struct name = __RCU_SYNC_INITIALIZER(name, type) | |
76 | ||
77 | #define DEFINE_RCU_SYNC(name) \ | |
78 | __DEFINE_RCU_SYNC(name, RCU_SYNC) | |
79 | ||
80 | #define DEFINE_RCU_SCHED_SYNC(name) \ | |
81 | __DEFINE_RCU_SYNC(name, RCU_SCHED_SYNC) | |
82 | ||
83 | #define DEFINE_RCU_BH_SYNC(name) \ | |
84 | __DEFINE_RCU_SYNC(name, RCU_BH_SYNC) | |
85 | ||
cc44ca84 | 86 | #endif /* _LINUX_RCU_SYNC_H_ */ |