OpenE2K
/
linux
6
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

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>
This commit is contained in:
Michael S. Tsirkin 2015-12-27 18:02:16 +02:00
parent 506b02eb1c
commit 234927540e
1 changed files with 2 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/xen/events/events_fifo.c
View File

@ -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];
}