On Fri, 2018-05-04 at 13:49 +0200, Evgenii Smirnov wrote:
> Currently, the validity of a path is checked only on
> unicast ARP transmission. If Subnet Manager switchover happens and
> some LIDs get reassigned, driver in a network that uses only IPv6
> addresses will not try to renew the path records, despite them
> being marked as invalid.
Are we not getting a flush event in this case? If we are getting a
flush event, maybe we just aren't doing a heavy enough flush?
In general I don't have a problem for this patch, but I would prefer to
find a solution that resolves the UD case too, and maybe that just needs
to flush harder on the specific event we get when we get a new SM (it's
a rereg event, yes?).
> In connected mode, remote side LID change will cause send to fail,
> freeing the corresponding neigh struct. Subsequent packets to this
> destination will trigger allocation of a new neigh struct.
>
> With this patch allocation of new neigh struct will also check the
> validity of the associated path and renew it if necessary.
>
> This, however, will not help in datagram mode, if the host
> continuously sends data to the destination with invalid path.
> The neigh struct alive timer will be updated, thus preventing
> it from reallocation.
>
> Test setup consists of two target hosts and two initiator hosts,
> one of the initiators is with the patch. All hosts have only IPv6
> addresses from the same subnet and initiators constantly ping targets.
> In connected mode swapping the LIDs of target hosts and switching over SM
> leads to the loss of connectivity for the initiator without the patch.
> Initiator with the patch recovers in ~3 sec. In datagram mode initiator
> with the patch is able to recover only if ping is stopped for
> neigh_obsolete time.
>
> Signed-off-by: Evgenii Smirnov <evgenii.smirnov@xxxxxxxxxxxxxxxx>
> ---
> drivers/infiniband/ulp/ipoib/ipoib_main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
> index 161ba8c76285..db5762d62aea 100644
> --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
> +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
> @@ -963,7 +963,7 @@ static struct ipoib_neigh *neigh_add_path(struct sk_buff *skb, u8 *daddr,
>
> list_add_tail(&neigh->list, &path->neigh_list);
>
> - if (path->ah) {
> + if (path->ah && path->valid) {
> kref_get(&path->ah->ref);
> neigh->ah = path->ah;
>
--
Doug Ledford <dledford@xxxxxxxxxx>
GPG KeyID: B826A3330E572FDD
Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDDAttachment:
signature.asc
Description: This is a digitally signed message part
