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authorPeter Zijlstra <peterz@infradead.org>2016-06-01 20:23:54 +0300
committerIngo Molnar <mingo@kernel.org>2016-06-14 12:55:14 +0300
commit7cb45c0fe9858f92cc264f6bf9d2f6a0e7d3b249 (patch)
treef429581d6b993e303a297a461d06cd0dad58ea68 /include/linux/compiler.h
parent33ac279677dcc2441cb93d8cb9cf7a74df62814d (diff)
downloadlinux-7cb45c0fe9858f92cc264f6bf9d2f6a0e7d3b249.tar.xz
locking/barriers: Move smp_cond_load_acquire() to asm-generic/barrier.h
Since all asm/barrier.h should/must include asm-generic/barrier.h the latter is a good place for generic infrastructure like this. This also allows archs to override the new smp_acquire__after_ctrl_dep(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/compiler.h')
-rw-r--r--include/linux/compiler.h37
1 files changed, 0 insertions, 37 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 59a7004fc7dd..2e853b679a5d 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -304,43 +304,6 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
__u.__val; \
})
-/**
- * smp_acquire__after_ctrl_dep() - Provide ACQUIRE ordering after a control dependency
- *
- * A control dependency provides a LOAD->STORE order, the additional RMB
- * provides LOAD->LOAD order, together they provide LOAD->{LOAD,STORE} order,
- * aka. (load)-ACQUIRE.
- *
- * Architectures that do not do load speculation can have this be barrier().
- */
-#define smp_acquire__after_ctrl_dep() smp_rmb()
-
-/**
- * smp_cond_load_acquire() - (Spin) wait for cond with ACQUIRE ordering
- * @ptr: pointer to the variable to wait on
- * @cond: boolean expression to wait for
- *
- * Equivalent to using smp_load_acquire() on the condition variable but employs
- * the control dependency of the wait to reduce the barrier on many platforms.
- *
- * Due to C lacking lambda expressions we load the value of *ptr into a
- * pre-named variable @VAL to be used in @cond.
- */
-#ifndef smp_cond_load_acquire
-#define smp_cond_load_acquire(ptr, cond_expr) ({ \
- typeof(ptr) __PTR = (ptr); \
- typeof(*ptr) VAL; \
- for (;;) { \
- VAL = READ_ONCE(*__PTR); \
- if (cond_expr) \
- break; \
- cpu_relax(); \
- } \
- smp_acquire__after_ctrl_dep(); \
- VAL; \
-})
-#endif
-
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */