From: Heiko Carstens <hca@linux.ibm.com>
Date: Mon, 25 Nov 2024 11:54:30 +0000 (+0100)
Subject: s390/ap: Replace xchg() with WRITE_ONCE()
X-Git-Tag: microblaze-v6.16~498^2~17
X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=7726b55b5d6c22dc0e66570597bf6e43d410d093;p=linux-2.6-microblaze.git

s390/ap: Replace xchg() with WRITE_ONCE()

The result of xchg() is not used, and in addition it is used on a one byte
memory area which leads to inefficient code.

Use WRITE_ONCE() instead to achieve the same result with much less
generated code.

Acked-by: Harald Freudenberger <freude@linux.ibm.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---

diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index e14638936de6..26e1ea1940ec 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -453,7 +453,7 @@ static void ap_tasklet_fn(unsigned long dummy)
 	 * important that no requests on any AP get lost.
 	 */
 	if (ap_irq_flag)
-		xchg(ap_airq.lsi_ptr, 0);
+		WRITE_ONCE(*ap_airq.lsi_ptr, 0);
 
 	spin_lock_bh(&ap_queues_lock);
 	hash_for_each(ap_queues, bkt, aq, hnode) {