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-rw-r--r--include/linux/compiler.h12
-rw-r--r--include/linux/rcupdate.h12
2 files changed, 12 insertions, 12 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index dcae0c8d97e6..c8bd2daf95ec 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -182,4 +182,16 @@ extern void __chk_io_ptr(const volatile void __iomem *);
182# define __section(S) __attribute__ ((__section__(#S))) 182# define __section(S) __attribute__ ((__section__(#S)))
183#endif 183#endif
184 184
185/*
186 * Prevent the compiler from merging or refetching accesses. The compiler
187 * is also forbidden from reordering successive instances of ACCESS_ONCE(),
188 * but only when the compiler is aware of some particular ordering. One way
189 * to make the compiler aware of ordering is to put the two invocations of
190 * ACCESS_ONCE() in different C statements.
191 *
192 * This macro does absolutely -nothing- to prevent the CPU from reordering,
193 * merging, or refetching absolutely anything at any time.
194 */
195#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
196
185#endif /* __LINUX_COMPILER_H */ 197#endif /* __LINUX_COMPILER_H */
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 8082d6587a0f..d42dbec06083 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -131,18 +131,6 @@ struct rcu_head {
131 */ 131 */
132#define rcu_read_unlock_bh() __rcu_read_unlock_bh() 132#define rcu_read_unlock_bh() __rcu_read_unlock_bh()
133 133
134/*
135 * Prevent the compiler from merging or refetching accesses. The compiler
136 * is also forbidden from reordering successive instances of ACCESS_ONCE(),
137 * but only when the compiler is aware of some particular ordering. One way
138 * to make the compiler aware of ordering is to put the two invocations of
139 * ACCESS_ONCE() in different C statements.
140 *
141 * This macro does absolutely -nothing- to prevent the CPU from reordering,
142 * merging, or refetching absolutely anything at any time.
143 */
144#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
145
146/** 134/**
147 * rcu_dereference - fetch an RCU-protected pointer in an 135 * rcu_dereference - fetch an RCU-protected pointer in an
148 * RCU read-side critical section. This pointer may later 136 * RCU read-side critical section. This pointer may later