ARC: remove redundant READ_ONCE() in cmpxchg loop

This patch reverts commit 7082a29 ("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 d57f727 ("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>
ChiShao · Apr 18, 2022 · c6ed4d8 · c6ed4d8
1 parent ac411e4
commit c6ed4d8
Showing 1 changed file with 1 addition and 1 deletion.
diff --git 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);