Commit c6ed4d84 authored Mar 19, 2022 by Bang Li Committed by Vineet Gupta Apr 18, 2022

ARC: remove redundant READ_ONCE() in cmpxchg loop



This patch reverts commit 7082a29c ("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 d57f7272 ("ARC: add compiler barrier to LLSC
based cmpxchg").

Signed-off-by: Bang Li <libang.linuxer@gmail.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

parent ac411e41

arch/arc/kernel/smp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);