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| 1 | +/* SPDX-License-Identifier: GPL-2.0+ */ |
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| 1 | 2 | /* |
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| 2 | 3 | * RCU-based infrastructure for lightweight reader-writer locking |
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| 3 | | - * |
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| 4 | | - * This program is free software; you can redistribute it and/or modify |
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| 5 | | - * it under the terms of the GNU General Public License as published by |
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| 6 | | - * the Free Software Foundation; either version 2 of the License, or |
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| 7 | | - * (at your option) any later version. |
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| 8 | | - * |
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| 9 | | - * This program is distributed in the hope that it will be useful, |
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| 10 | | - * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | | - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 12 | | - * GNU General Public License for more details. |
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| 13 | | - * |
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| 14 | | - * You should have received a copy of the GNU General Public License |
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| 15 | | - * along with this program; if not, you can access it online at |
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| 16 | | - * http://www.gnu.org/licenses/gpl-2.0.html. |
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| 17 | 4 | * |
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| 18 | 5 | * Copyright (c) 2015, Red Hat, Inc. |
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| 19 | 6 | * |
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| .. | .. |
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| 26 | 13 | #include <linux/wait.h> |
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| 27 | 14 | #include <linux/rcupdate.h> |
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| 28 | 15 | |
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| 29 | | -enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC }; |
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| 30 | | - |
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| 31 | 16 | /* Structure to mediate between updaters and fastpath-using readers. */ |
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| 32 | 17 | struct rcu_sync { |
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| 33 | 18 | int gp_state; |
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| 34 | 19 | int gp_count; |
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| 35 | 20 | wait_queue_head_t gp_wait; |
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| 36 | 21 | |
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| 37 | | - int cb_state; |
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| 38 | 22 | struct rcu_head cb_head; |
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| 39 | | - |
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| 40 | | - enum rcu_sync_type gp_type; |
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| 41 | 23 | }; |
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| 42 | | - |
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| 43 | | -extern void rcu_sync_lockdep_assert(struct rcu_sync *); |
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| 44 | 24 | |
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| 45 | 25 | /** |
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| 46 | 26 | * rcu_sync_is_idle() - Are readers permitted to use their fastpaths? |
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| 47 | 27 | * @rsp: Pointer to rcu_sync structure to use for synchronization |
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| 48 | 28 | * |
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| 49 | | - * Returns true if readers are permitted to use their fastpaths. |
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| 50 | | - * Must be invoked within an RCU read-side critical section whose |
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| 51 | | - * flavor matches that of the rcu_sync struture. |
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| 29 | + * Returns true if readers are permitted to use their fastpaths. Must be |
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| 30 | + * invoked within some flavor of RCU read-side critical section. |
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| 52 | 31 | */ |
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| 53 | 32 | static inline bool rcu_sync_is_idle(struct rcu_sync *rsp) |
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| 54 | 33 | { |
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| 55 | | -#ifdef CONFIG_PROVE_RCU |
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| 56 | | - rcu_sync_lockdep_assert(rsp); |
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| 57 | | -#endif |
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| 58 | | - return !rsp->gp_state; /* GP_IDLE */ |
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| 34 | + RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(), |
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| 35 | + "suspicious rcu_sync_is_idle() usage"); |
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| 36 | + return !READ_ONCE(rsp->gp_state); /* GP_IDLE */ |
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| 59 | 37 | } |
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| 60 | 38 | |
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| 61 | | -extern void rcu_sync_init(struct rcu_sync *, enum rcu_sync_type); |
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| 39 | +extern void rcu_sync_init(struct rcu_sync *); |
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| 62 | 40 | extern void rcu_sync_enter_start(struct rcu_sync *); |
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| 63 | 41 | extern void rcu_sync_enter(struct rcu_sync *); |
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| 64 | 42 | extern void rcu_sync_exit(struct rcu_sync *); |
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| 65 | 43 | extern void rcu_sync_dtor(struct rcu_sync *); |
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| 66 | 44 | |
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| 67 | | -#define __RCU_SYNC_INITIALIZER(name, type) { \ |
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| 45 | +#define __RCU_SYNC_INITIALIZER(name) { \ |
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| 68 | 46 | .gp_state = 0, \ |
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| 69 | 47 | .gp_count = 0, \ |
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| 70 | 48 | .gp_wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.gp_wait), \ |
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| 71 | | - .cb_state = 0, \ |
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| 72 | | - .gp_type = type, \ |
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| 73 | 49 | } |
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| 74 | 50 | |
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| 75 | | -#define __DEFINE_RCU_SYNC(name, type) \ |
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| 76 | | - struct rcu_sync_struct name = __RCU_SYNC_INITIALIZER(name, type) |
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| 77 | | - |
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| 78 | | -#define DEFINE_RCU_SYNC(name) \ |
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| 79 | | - __DEFINE_RCU_SYNC(name, RCU_SYNC) |
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| 80 | | - |
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| 81 | | -#define DEFINE_RCU_SCHED_SYNC(name) \ |
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| 82 | | - __DEFINE_RCU_SYNC(name, RCU_SCHED_SYNC) |
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| 83 | | - |
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| 84 | | -#define DEFINE_RCU_BH_SYNC(name) \ |
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| 85 | | - __DEFINE_RCU_SYNC(name, RCU_BH_SYNC) |
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| 51 | +#define DEFINE_RCU_SYNC(name) \ |
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| 52 | + struct rcu_sync name = __RCU_SYNC_INITIALIZER(name) |
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| 86 | 53 | |
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| 87 | 54 | #endif /* _LINUX_RCU_SYNC_H_ */ |
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