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| author |   Michael S. Tsirkin <mst@redhat.com> | 2015-12-27 18:02:16 +0200 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2016-01-12 20:47:04 +0200 |
| commit | 234927540e6ac82f5f083a11c3e860e346ed09bc (patch) | |
| tree | 8b3a2ba97c047685bd8272abef5c5e5ec1f18061 /drivers/xen | |
| parent | xen/io: use virt_xxx barriers (diff) | |
| download | linux-dev-234927540e6ac82f5f083a11c3e860e346ed09bc.tar.xz linux-dev-234927540e6ac82f5f083a11c3e860e346ed09bc.zip | |
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.c | 3 |
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]; } |