[71/88] drivers: hv: switch to use mb() instead of smp_mb()

From: Steven Rostedt
Date: Tue Aug 13 2013 - 12:33:18 EST stable review patch.
If anyone has any objections, please let me know.


From: Jason Wang <jasowang@xxxxxxxxxx>

[ Upstream commit 35848f68b07df3f917cb13fc3c134718669f569b ]

Even if guest were compiled without SMP support, it could not assume that host
wasn't. So switch to use mb() instead of smp_mb() to force memory barriers for
UP guest.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
drivers/hv/ring_buffer.c | 2 +-
drivers/hv/vmbus_drv.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 7233c88..14aa6fe 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -454,7 +454,7 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer,
/* Make sure all reads are done before we update the read index since */
/* the writer may start writing to the read area once the read index */
/*is updated */
- smp_mb();
+ mb();

/* Update the read index */
hv_set_next_read_location(inring_info, next_read_location);
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 4748086..db5fc10 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -466,7 +466,7 @@ static void vmbus_on_msg_dpc(unsigned long data)
* will not deliver any more messages since there is
* no empty slot
- smp_mb();
+ mb();

if (msg->header.message_flags.msg_pending) {

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