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authorMichael S. Tsirkin <mst@redhat.com>2015-12-27 18:02:16 +0200
committerMichael S. Tsirkin <mst@redhat.com>2016-01-12 20:47:04 +0200
commit234927540e6ac82f5f083a11c3e860e346ed09bc (patch)
tree8b3a2ba97c047685bd8272abef5c5e5ec1f18061 /drivers/xen
parent506b02eb1cf79838b76c6e3e43171cf960f01fc8 (diff)
xen/events: use virt_xxx barriers
drivers/xen/events/events_fifo.c uses rmb() to communicate with the other side. For guests compiled with CONFIG_SMP, smp_rmb would be sufficient, so rmb() here is only needed if a non-SMP guest runs on an SMP host. Switch to the virt_rmb barrier which serves this exact purpose. Pull in asm/barrier.h here to make sure the file is self-contained. Suggested-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/events/events_fifo.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index 96a1b8da5371..eff2b88003d9 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -41,6 +41,7 @@
#include <linux/percpu.h>
#include <linux/cpu.h>
+#include <asm/barrier.h>
#include <asm/sync_bitops.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/hypervisor.h>
@@ -296,7 +297,7 @@ static void consume_one_event(unsigned cpu,
* control block.
*/
if (head == 0) {
- rmb(); /* Ensure word is up-to-date before reading head. */
+ virt_rmb(); /* Ensure word is up-to-date before reading head. */
head = control_block->head[priority];
}