> -----Original Message-----
> From: Jason Wang [mailto:jasow...@redhat.com]
> Sent: Tuesday, June 18, 2013 1:04 AM
> To: KY Srinivasan; Haiyang Zhang; de...@linuxdriverproject.org; linux-
> ker...@vger.kernel.org
> Cc: Jason Wang; stable@vger.kernel.org
> Subject: [PATCH] drivers: hv: switch to use mb() instead of smp_mb()
>
> 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.
>
> Cc: K. Y. Srinivasan <k...@microsoft.com>
> Cc: Haiyang Zhang <haiya...@microsoft.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Jason Wang <jasow...@redhat.com>
Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
> ---
> drivers/hv/ring_buffer.c | 10 +++++-----
> drivers/hv/vmbus_drv.c | 2 +-
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
> index d6fbb57..791f45d 100644
> --- a/drivers/hv/ring_buffer.c
> +++ b/drivers/hv/ring_buffer.c
> @@ -32,7 +32,7 @@
> void hv_begin_read(struct hv_ring_buffer_info *rbi)
> {
> rbi->ring_buffer->interrupt_mask = 1;
> - smp_mb();
> + mb();
> }
>
> u32 hv_end_read(struct hv_ring_buffer_info *rbi)
> @@ -41,7 +41,7 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi)
> u32 write;
>
> rbi->ring_buffer->interrupt_mask = 0;
> - smp_mb();
> + mb();
>
> /*
> * Now check to see if the ring buffer is still empty.
> @@ -71,7 +71,7 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi)
>
> static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi)
> {
> - smp_mb();
> + mb();
> if (rbi->ring_buffer->interrupt_mask)
> return false;
>
> @@ -442,7 +442,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info
> *outring_info,
> sizeof(u64));
>
> /* Issue a full memory barrier before updating the write index */
> - smp_mb();
> + mb();
>
> /* Now, update the write location */
> hv_set_next_write_location(outring_info, next_write_location);
> @@ -549,7 +549,7 @@ 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 bf421e0..4004e54 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -434,7 +434,7 @@ 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) {
> /*
> --
> 1.7.1
>
>
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