Add the acquire variant of smp_cond_load_relaxed_timewait(). This
reuses the relaxed variant, with the additional LOAD->LOAD
ordering via smp_acquire__after_ctrl_dep().
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Signed-off-by: Ankur Arora <ankur.a.arora@xxxxxxxxxx>
---
include/asm-generic/barrier.h | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h
index 76124683be4b..2d52dc5b82fe 100644
--- a/include/asm-generic/barrier.h
+++ b/include/asm-generic/barrier.h
@@ -397,6 +397,32 @@ static inline u64 ___cond_spinwait(u64 now, u64 prev, u64 end,
(typeof(*ptr))_val; \
})
+/**
+ * smp_cond_load_acquire_timewait() - (Spin) wait for cond with ACQUIRE ordering
+ * until a timeout expires.
+ * @ptr: pointer to the variable to wait on
+ * @cond: boolean expression to wait for
+ * @wait_policy: policy handler that adjusts how much we spin before evaluating
+ * the timeout, and if we drop into a wait for cacheline to change (depending
+ * on architecture support.)
+ * @time_expr: monotonic expression that evaluates to the current time
+ * @time_end: compared against time_expr
+ *
+ * Equivalent to using smp_cond_load_acquire() on the condition variable with
+ * a timeout.
+ */
+#ifndef smp_cond_load_acquire_timewait
+#define smp_cond_load_acquire_timewait(ptr, cond_expr, wait_policy, \
+ time_expr, time_end) ({ \
+ __unqual_scalar_typeof(*ptr) _val; \
+ _val = smp_cond_load_relaxed_timewait(ptr, cond_expr, \
+ wait_policy, time_expr, \
+ time_end); \
+ /* Depends on the control dependency of the wait above. */ \
+ smp_acquire__after_ctrl_dep(); \
+ (typeof(*ptr))_val; \
+})
+#endif
/*
* pmem_wmb() ensures that all stores for which the modification
* are written to persistent storage by preceding instructions have
--
2.43.5
