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2024-05-10 093a6c67005148ae32a5c9e4553491b9f5c2457b 
 kernel/include/linux/srcu.h
....@@ -1,24 +1,11 @@
1
+/* SPDX-License-Identifier: GPL-2.0+ */
12 /*
23  * Sleepable Read-Copy Update mechanism for mutual exclusion
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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.
174  *
185  * Copyright (C) IBM Corporation, 2006
196  * Copyright (C) Fujitsu, 2012
207  *
21
- * Author: Paul McKenney <paulmck@us.ibm.com>
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+ * Author: Paul McKenney <paulmck@linux.ibm.com>
229  *	   Lai Jiangshan <laijs@cn.fujitsu.com>
2310  *
2411  * For detailed explanation of Read-Copy Update mechanism see -
....@@ -38,20 +25,20 @@
3825 
3926 #ifdef CONFIG_DEBUG_LOCK_ALLOC
4027 
41
-int __init_srcu_struct(struct srcu_struct *sp, const char *name,
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+int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
4229 		       struct lock_class_key *key);
4330 
44
-#define init_srcu_struct(sp) \
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+#define init_srcu_struct(ssp) \
4532 ({ \
4633 	static struct lock_class_key __srcu_key; \
4734 	\
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-	__init_srcu_struct((sp), #sp, &__srcu_key); \
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+	__init_srcu_struct((ssp), #ssp, &__srcu_key); \
4936 })
5037 
5138 #define __SRCU_DEP_MAP_INIT(srcu_name)	.dep_map = { .name = #srcu_name },
5239 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
5340 
54
-int init_srcu_struct(struct srcu_struct *sp);
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+int init_srcu_struct(struct srcu_struct *ssp);
5542 
5643 #define __SRCU_DEP_MAP_INIT(srcu_name)
5744 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
....@@ -67,52 +54,21 @@
6754 struct srcu_struct { };
6855 #endif
6956 
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-void call_srcu(struct srcu_struct *sp, struct rcu_head *head,
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+void call_srcu(struct srcu_struct *ssp, struct rcu_head *head,
7158 		void (*func)(struct rcu_head *head));
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-void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced);
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-int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp);
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-void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);
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-void synchronize_srcu(struct srcu_struct *sp);
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-
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-/**
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- * cleanup_srcu_struct - deconstruct a sleep-RCU structure
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- * @sp: structure to clean up.
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- *
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- * Must invoke this after you are finished using a given srcu_struct that
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- * was initialized via init_srcu_struct(), else you leak memory.
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- */
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-static inline void cleanup_srcu_struct(struct srcu_struct *sp)
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-{
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-	_cleanup_srcu_struct(sp, false);
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-}
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-
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-/**
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- * cleanup_srcu_struct_quiesced - deconstruct a quiesced sleep-RCU structure
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- * @sp: structure to clean up.
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- *
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- * Must invoke this after you are finished using a given srcu_struct that
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- * was initialized via init_srcu_struct(), else you leak memory.  Also,
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- * all grace-period processing must have completed.
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- *
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- * "Completed" means that the last synchronize_srcu() and
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- * synchronize_srcu_expedited() calls must have returned before the call
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- * to cleanup_srcu_struct_quiesced().  It also means that the callback
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- * from the last call_srcu() must have been invoked before the call to
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- * cleanup_srcu_struct_quiesced(), but you can use srcu_barrier() to help
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- * with this last.  Violating these rules will get you a WARN_ON() splat
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- * (with high probability, anyway), and will also cause the srcu_struct
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- * to be leaked.
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- */
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-static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *sp)
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-{
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-	_cleanup_srcu_struct(sp, true);
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-}
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+void cleanup_srcu_struct(struct srcu_struct *ssp);
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+int __srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp);
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+void __srcu_read_unlock(struct srcu_struct *ssp, int idx) __releases(ssp);
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+void synchronize_srcu(struct srcu_struct *ssp);
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+unsigned long get_state_synchronize_srcu(struct srcu_struct *ssp);
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+unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp);
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+bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie);
11066 
11167 #ifdef CONFIG_DEBUG_LOCK_ALLOC
11268 
11369 /**
11470  * srcu_read_lock_held - might we be in SRCU read-side critical section?
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- * @sp: The srcu_struct structure to check
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+ * @ssp: The srcu_struct structure to check
11672  *
11773  * If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an SRCU
11874  * read-side critical section.  In absence of CONFIG_DEBUG_LOCK_ALLOC,
....@@ -126,16 +82,16 @@
12682  * relies on normal RCU, it can be called from the CPU which
12783  * is in the idle loop from an RCU point of view or offline.
12884  */
129
-static inline int srcu_read_lock_held(const struct srcu_struct *sp)
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+static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
13086 {
13187 	if (!debug_lockdep_rcu_enabled())
13288 		return 1;
133
-	return lock_is_held(&sp->dep_map);
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+	return lock_is_held(&ssp->dep_map);
13490 }
13591 
13692 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
13793 
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-static inline int srcu_read_lock_held(const struct srcu_struct *sp)
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+static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
13995 {
14096 	return 1;
14197 }
....@@ -145,7 +101,7 @@
145101 /**
146102  * srcu_dereference_check - fetch SRCU-protected pointer for later dereferencing
147103  * @p: the pointer to fetch and protect for later dereferencing
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- * @sp: pointer to the srcu_struct, which is used to check that we
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+ * @ssp: pointer to the srcu_struct, which is used to check that we
149105  *	really are in an SRCU read-side critical section.
150106  * @c: condition to check for update-side use
151107  *
....@@ -154,29 +110,32 @@
154110  * to 1.  The @c argument will normally be a logical expression containing
155111  * lockdep_is_held() calls.
156112  */
157
-#define srcu_dereference_check(p, sp, c) \
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-	__rcu_dereference_check((p), (c) || srcu_read_lock_held(sp), __rcu)
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+#define srcu_dereference_check(p, ssp, c) \
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+	__rcu_dereference_check((p), (c) || srcu_read_lock_held(ssp), __rcu)
159115 
160116 /**
161117  * srcu_dereference - fetch SRCU-protected pointer for later dereferencing
162118  * @p: the pointer to fetch and protect for later dereferencing
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- * @sp: pointer to the srcu_struct, which is used to check that we
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+ * @ssp: pointer to the srcu_struct, which is used to check that we
164120  *	really are in an SRCU read-side critical section.
165121  *
166122  * Makes rcu_dereference_check() do the dirty work.  If PROVE_RCU
167123  * is enabled, invoking this outside of an RCU read-side critical
168124  * section will result in an RCU-lockdep splat.
169125  */
170
-#define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0)
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+#define srcu_dereference(p, ssp) srcu_dereference_check((p), (ssp), 0)
171127 
172128 /**
173129  * srcu_dereference_notrace - no tracing and no lockdep calls from here
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+ * @p: the pointer to fetch and protect for later dereferencing
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+ * @ssp: pointer to the srcu_struct, which is used to check that we
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+ *	really are in an SRCU read-side critical section.
174133  */
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-#define srcu_dereference_notrace(p, sp) srcu_dereference_check((p), (sp), 1)
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+#define srcu_dereference_notrace(p, ssp) srcu_dereference_check((p), (ssp), 1)
176135 
177136 /**
178137  * srcu_read_lock - register a new reader for an SRCU-protected structure.
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- * @sp: srcu_struct in which to register the new reader.
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+ * @ssp: srcu_struct in which to register the new reader.
180139  *
181140  * Enter an SRCU read-side critical section.  Note that SRCU read-side
182141  * critical sections may be nested.  However, it is illegal to
....@@ -191,44 +150,45 @@
191150  * srcu_read_unlock() in an irq handler if the matching srcu_read_lock()
192151  * was invoked in process context.
193152  */
194
-static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
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+static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp)
195154 {
196155 	int retval;
197156 
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-	retval = __srcu_read_lock(sp);
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-	rcu_lock_acquire(&(sp)->dep_map);
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+	retval = __srcu_read_lock(ssp);
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+	rcu_lock_acquire(&(ssp)->dep_map);
200159 	return retval;
201160 }
202161 
203162 /* Used by tracing, cannot be traced and cannot invoke lockdep. */
204163 static inline notrace int
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-srcu_read_lock_notrace(struct srcu_struct *sp) __acquires(sp)
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+srcu_read_lock_notrace(struct srcu_struct *ssp) __acquires(ssp)
206165 {
207166 	int retval;
208167 
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-	retval = __srcu_read_lock(sp);
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+	retval = __srcu_read_lock(ssp);
210169 	return retval;
211170 }
212171 
213172 /**
214173  * srcu_read_unlock - unregister a old reader from an SRCU-protected structure.
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- * @sp: srcu_struct in which to unregister the old reader.
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+ * @ssp: srcu_struct in which to unregister the old reader.
216175  * @idx: return value from corresponding srcu_read_lock().
217176  *
218177  * Exit an SRCU read-side critical section.
219178  */
220
-static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
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-	__releases(sp)
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+static inline void srcu_read_unlock(struct srcu_struct *ssp, int idx)
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+	__releases(ssp)
222181 {
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-	rcu_lock_release(&(sp)->dep_map);
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-	__srcu_read_unlock(sp, idx);
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+	WARN_ON_ONCE(idx & ~0x1);
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+	rcu_lock_release(&(ssp)->dep_map);
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+	__srcu_read_unlock(ssp, idx);
225185 }
226186 
227187 /* Used by tracing, cannot be traced and cannot call lockdep. */
228188 static inline notrace void
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-srcu_read_unlock_notrace(struct srcu_struct *sp, int idx) __releases(sp)
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+srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp)
230190 {
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-	__srcu_read_unlock(sp, idx);
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+	__srcu_read_unlock(ssp, idx);
232192 }
233193 
234194 /**