aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/srcu.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/srcu.c')
-rw-r--r--kernel/srcu.c52
1 files changed, 34 insertions, 18 deletions
diff --git a/kernel/srcu.c b/kernel/srcu.c
index 818d7d9aa03c..bde4295774c8 100644
--- a/kernel/srcu.c
+++ b/kernel/srcu.c
@@ -34,6 +34,30 @@
34#include <linux/smp.h> 34#include <linux/smp.h>
35#include <linux/srcu.h> 35#include <linux/srcu.h>
36 36
37static int init_srcu_struct_fields(struct srcu_struct *sp)
38{
39 sp->completed = 0;
40 mutex_init(&sp->mutex);
41 sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array);
42 return sp->per_cpu_ref ? 0 : -ENOMEM;
43}
44
45#ifdef CONFIG_DEBUG_LOCK_ALLOC
46
47int __init_srcu_struct(struct srcu_struct *sp, const char *name,
48 struct lock_class_key *key)
49{
50#ifdef CONFIG_DEBUG_LOCK_ALLOC
51 /* Don't re-initialize a lock while it is held. */
52 debug_check_no_locks_freed((void *)sp, sizeof(*sp));
53 lockdep_init_map(&sp->dep_map, name, key, 0);
54#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
55 return init_srcu_struct_fields(sp);
56}
57EXPORT_SYMBOL_GPL(__init_srcu_struct);
58
59#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
60
37/** 61/**
38 * init_srcu_struct - initialize a sleep-RCU structure 62 * init_srcu_struct - initialize a sleep-RCU structure
39 * @sp: structure to initialize. 63 * @sp: structure to initialize.
@@ -44,13 +68,12 @@
44 */ 68 */
45int init_srcu_struct(struct srcu_struct *sp) 69int init_srcu_struct(struct srcu_struct *sp)
46{ 70{
47 sp->completed = 0; 71 return init_srcu_struct_fields(sp);
48 mutex_init(&sp->mutex);
49 sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array);
50 return (sp->per_cpu_ref ? 0 : -ENOMEM);
51} 72}
52EXPORT_SYMBOL_GPL(init_srcu_struct); 73EXPORT_SYMBOL_GPL(init_srcu_struct);
53 74
75#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
76
54/* 77/*
55 * srcu_readers_active_idx -- returns approximate number of readers 78 * srcu_readers_active_idx -- returns approximate number of readers
56 * active on the specified rank of per-CPU counters. 79 * active on the specified rank of per-CPU counters.
@@ -100,15 +123,12 @@ void cleanup_srcu_struct(struct srcu_struct *sp)
100} 123}
101EXPORT_SYMBOL_GPL(cleanup_srcu_struct); 124EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
102 125
103/** 126/*
104 * srcu_read_lock - register a new reader for an SRCU-protected structure.
105 * @sp: srcu_struct in which to register the new reader.
106 *
107 * Counts the new reader in the appropriate per-CPU element of the 127 * Counts the new reader in the appropriate per-CPU element of the
108 * srcu_struct. Must be called from process context. 128 * srcu_struct. Must be called from process context.
109 * Returns an index that must be passed to the matching srcu_read_unlock(). 129 * Returns an index that must be passed to the matching srcu_read_unlock().
110 */ 130 */
111int srcu_read_lock(struct srcu_struct *sp) 131int __srcu_read_lock(struct srcu_struct *sp)
112{ 132{
113 int idx; 133 int idx;
114 134
@@ -120,31 +140,27 @@ int srcu_read_lock(struct srcu_struct *sp)
120 preempt_enable(); 140 preempt_enable();
121 return idx; 141 return idx;
122} 142}
123EXPORT_SYMBOL_GPL(srcu_read_lock); 143EXPORT_SYMBOL_GPL(__srcu_read_lock);
124 144
125/** 145/*
126 * srcu_read_unlock - unregister a old reader from an SRCU-protected structure.
127 * @sp: srcu_struct in which to unregister the old reader.
128 * @idx: return value from corresponding srcu_read_lock().
129 *
130 * Removes the count for the old reader from the appropriate per-CPU 146 * Removes the count for the old reader from the appropriate per-CPU
131 * element of the srcu_struct. Note that this may well be a different 147 * element of the srcu_struct. Note that this may well be a different
132 * CPU than that which was incremented by the corresponding srcu_read_lock(). 148 * CPU than that which was incremented by the corresponding srcu_read_lock().
133 * Must be called from process context. 149 * Must be called from process context.
134 */ 150 */
135void srcu_read_unlock(struct srcu_struct *sp, int idx) 151void __srcu_read_unlock(struct srcu_struct *sp, int idx)
136{ 152{
137 preempt_disable(); 153 preempt_disable();
138 srcu_barrier(); /* ensure compiler won't misorder critical section. */ 154 srcu_barrier(); /* ensure compiler won't misorder critical section. */
139 per_cpu_ptr(sp->per_cpu_ref, smp_processor_id())->c[idx]--; 155 per_cpu_ptr(sp->per_cpu_ref, smp_processor_id())->c[idx]--;
140 preempt_enable(); 156 preempt_enable();
141} 157}
142EXPORT_SYMBOL_GPL(srcu_read_unlock); 158EXPORT_SYMBOL_GPL(__srcu_read_unlock);
143 159
144/* 160/*
145 * Helper function for synchronize_srcu() and synchronize_srcu_expedited(). 161 * Helper function for synchronize_srcu() and synchronize_srcu_expedited().
146 */ 162 */
147void __synchronize_srcu(struct srcu_struct *sp, void (*sync_func)(void)) 163static void __synchronize_srcu(struct srcu_struct *sp, void (*sync_func)(void))
148{ 164{
149 int idx; 165 int idx;
150 166