From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Thu, 26 Mar 2009 14:24:10 +0000 (+0100)
Subject: [S390] cio: ensure single load of irq handler pointer
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=87fa5af80cdd5053b27a546725948c2b74ec82b2;p=linux-beck.git

[S390] cio: ensure single load of irq handler pointer

Add barrier to prevent compiler from reloading pointer to irq handler.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

diff --git a/drivers/s390/cio/airq.c b/drivers/s390/cio/airq.c
index fe6cea15bbaf..d3850dc30e42 100644
--- a/drivers/s390/cio/airq.c
+++ b/drivers/s390/cio/airq.c
@@ -133,6 +133,8 @@ void do_adapter_IO(u8 isc)
 		while (word) {
 			if (word & INDICATOR_MASK) {
 				airq = airqs[isc][i];
+				/* Make sure gcc reads from airqs only once. */
+				barrier();
 				if (likely(airq))
 					airq->handler(&indicators[isc].byte[i],
 						      airq->drv_data);