From c6ed4d84a2c49de7d6f490144cca7b4a4831fb6e Mon Sep 17 00:00:00 2001 From: Bang Li Date: Sat, 19 Mar 2022 10:03:16 +0800 Subject: [PATCH] ARC: remove redundant READ_ONCE() in cmpxchg loop This patch reverts commit 7082a29c22ac ("ARC: use ACCESS_ONCE in cmpxchg loop"). It is not necessary to use READ_ONCE() because cmpxchg contains barrier. We can get it from commit d57f727264f1 ("ARC: add compiler barrier to LLSC based cmpxchg"). Signed-off-by: Bang Li Signed-off-by: Vineet Gupta --- arch/arc/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c index 383fefee2ae5..d947473f1e6d 100644 --- a/arch/arc/kernel/smp.c +++ b/arch/arc/kernel/smp.c @@ -274,7 +274,7 @@ static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg) * and read back old value */ do { - new = old = READ_ONCE(*ipi_data_ptr); + new = old = *ipi_data_ptr; new |= 1U << msg; } while (cmpxchg(ipi_data_ptr, old, new) != old);