Hi Hiroshi-san,
Please see my comments below.
On 03/11/2014 06:37 AM, Hiroshi Shimamoto wrote:
> From: Hiroshi Shimamoto <h-shimamoto at ct.jp.nec.com>
>
> There is a race condition, on transmit to vSwitch.
I think we should not talk specifically about vSwitch, as
another implementation of host memnic is possible. Maybe using
the term "host" is more appropriate?
> + if (idx != ACCESS_ONCE(adapter->down_idx)) {
> + /*
> + * vSwitch freed this and got false positive,
> + * need to recover the status and retry.
> + */
> + p->status = MEMNIC_PKT_ST_FREE;
> + goto retry;
> + }
> +
The patch indeed looks to improve reliability, even if it's
difficult to me to be sure that there is no other race condition.
Again, I would replace "vSwitch" by "host".
By the way, I guess the Linux code in linux/memnic_net.c should be
modified in the same way.
Regards,
Olivier
