Re: [dpdk-dev] [PATCH 1/4] net/vmbus: add missing barrier

[Ruifeng Wang <Ruifeng.Wang@arm.com>]

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Stephen Hemminger
> Sent: Tuesday, April 28, 2020 7:28 AM
> To: dev@dpdk.org
> Cc: Stephen Hemminger <stephen@networkplumber.org>
> Subject: [dpdk-dev] [PATCH 1/4] net/vmbus: add missing barrier
>
> The check for event ring being empty needs a barrier to avoid any over
> agressive optimization.
> This is same barrier as Linux kernel.
>
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
>  drivers/bus/vmbus/vmbus_channel.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/bus/vmbus/vmbus_channel.c
> b/drivers/bus/vmbus/vmbus_channel.c
> index 46b3ba3f9f9e..ff2985c25758 100644
> --- a/drivers/bus/vmbus/vmbus_channel.c
> +++ b/drivers/bus/vmbus/vmbus_channel.c
> @@ -199,6 +199,7 @@ bool rte_vmbus_chan_rx_empty(const struct
> vmbus_channel *channel)  {
>  const struct vmbus_br *br = &channel->rxbr;
>
> +rte_smp_rmb();
>  return br->vbr->rindex == br->vbr->windex;  }
>
> --
> 2.20.1

Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>

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