[RESEND PATCH v7 4/7] asm-generic: barrier: Add smp_cond_load_acquire_timeout()

Ankur Arora
2025-10-28T05:32:22Z

Add the acquire variant of smp_cond_load_relaxed_timeout(). This
reuses the relaxed variant, with an additional LOAD->LOAD
ordering.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-arch@vger.kernel.org
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Haris Okanovic <harisokn@amazon.com>
Tested-by: Haris Okanovic <harisokn@amazon.com>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
include/asm-generic/barrier.h | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)

diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h
index 0063b46ec065..9a218f558c5c 100644
--- a/include/asm-generic/barrier.h
+++ b/include/asm-generic/barrier.h
@@ -314,6 +314,28 @@ do { \
})
#endif

+/**
+ * smp_cond_load_acquire_timeout() - (Spin) wait for cond with ACQUIRE ordering
+ * until a timeout expires.
+ *
+ * Arguments: same as smp_cond_load_relaxed_timeout().
+ *
+ * Equivalent to using smp_cond_load_acquire() on the condition variable with
+ * a timeout.
+ */
+#ifndef smp_cond_load_acquire_timeout
+#define smp_cond_load_acquire_timeout(ptr, cond_expr, time_check_expr) \
+({ \
+ __unqual_scalar_typeof(*ptr) _val; \
+ _val = smp_cond_load_relaxed_timeout(ptr, cond_expr, \
+ time_check_expr); \
+ \
+ /* 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