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>

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__ */