write in 30M

hc

2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc

 kernel/include/linux/rcu_sync.h
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@@ -1,19 +1,6 @@
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+/* SPDX-License-Identifier: GPL-2.0+ */
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 /*
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  * RCU-based infrastructure for lightweight reader-writer locking
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License as published by
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- * the Free Software Foundation; either version 2 of the License, or
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- * (at your option) any later version.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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- * GNU General Public License for more details.
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- *
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- * You should have received a copy of the GNU General Public License
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- * along with this program; if not, you can access it online at
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- * http://www.gnu.org/licenses/gpl-2.0.html.
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  *
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  * Copyright (c) 2015, Red Hat, Inc.
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  *
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@@ -26,62 +13,42 @@
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 #include <linux/wait.h>
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 #include <linux/rcupdate.h>
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15
 
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-enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC };
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-
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 /* Structure to mediate between updaters and fastpath-using readers.  */
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 struct rcu_sync {
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 	int			gp_state;
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 	int			gp_count;
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 	wait_queue_head_t	gp_wait;
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-	int			cb_state;
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 	struct rcu_head		cb_head;
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-
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-	enum rcu_sync_type	gp_type;
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 };
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-
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-extern void rcu_sync_lockdep_assert(struct rcu_sync *);
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 /**
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  * rcu_sync_is_idle() - Are readers permitted to use their fastpaths?
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  * @rsp: Pointer to rcu_sync structure to use for synchronization
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  *
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- * Returns true if readers are permitted to use their fastpaths.
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- * Must be invoked within an RCU read-side critical section whose
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- * flavor matches that of the rcu_sync struture.
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+ * Returns true if readers are permitted to use their fastpaths.  Must be
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+ * invoked within some flavor of RCU read-side critical section.
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  */
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 static inline bool rcu_sync_is_idle(struct rcu_sync *rsp)
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 {
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-#ifdef CONFIG_PROVE_RCU
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-	rcu_sync_lockdep_assert(rsp);
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-#endif
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-	return !rsp->gp_state; /* GP_IDLE */
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+	RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(),
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+			 "suspicious rcu_sync_is_idle() usage");
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+	return !READ_ONCE(rsp->gp_state); /* GP_IDLE */
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 }
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-extern void rcu_sync_init(struct rcu_sync *, enum rcu_sync_type);
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+extern void rcu_sync_init(struct rcu_sync *);
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 extern void rcu_sync_enter_start(struct rcu_sync *);
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 extern void rcu_sync_enter(struct rcu_sync *);
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 extern void rcu_sync_exit(struct rcu_sync *);
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 extern void rcu_sync_dtor(struct rcu_sync *);
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-#define __RCU_SYNC_INITIALIZER(name, type) {				\
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+#define __RCU_SYNC_INITIALIZER(name) {					\
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 		.gp_state = 0,						\
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 		.gp_count = 0,						\
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 		.gp_wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.gp_wait),	\
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-		.cb_state = 0,						\
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-		.gp_type = type,					\
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 	}
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-#define	__DEFINE_RCU_SYNC(name, type)	\
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-	struct rcu_sync_struct name = __RCU_SYNC_INITIALIZER(name, type)
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-
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-#define DEFINE_RCU_SYNC(name)		\
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-	__DEFINE_RCU_SYNC(name, RCU_SYNC)
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-
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-#define DEFINE_RCU_SCHED_SYNC(name)	\
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-	__DEFINE_RCU_SYNC(name, RCU_SCHED_SYNC)
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-
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-#define DEFINE_RCU_BH_SYNC(name)	\
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-	__DEFINE_RCU_SYNC(name, RCU_BH_SYNC)
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+#define	DEFINE_RCU_SYNC(name)	\
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+	struct rcu_sync name = __RCU_SYNC_INITIALIZER(name)
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 #endif /* _LINUX_RCU_SYNC_H_ */