From: Eric Dumazet <eric.duma...@gmail.com>
Date: Thu, 24 Mar 2016 09:45:34 -0700
> On Thu, 2016-03-24 at 08:25 -0700, David Ahern wrote:
>> Multipath route lookups should consider knowledge about next hops and not
>> select a hop that is known to be failed.
>
> Does not look a net candidate to me.
>
>> Signed-off-by: David Ahern <d...@cumulusnetworks.com>
>> ---
>> net/ipv4/fib_semantics.c | 34 ++++++++++++++++++++++++++++++++--
>> 1 file changed, 32 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
>> index d97268e8ff10..28fc6700c2b1 100644
>> --- a/net/ipv4/fib_semantics.c
>> +++ b/net/ipv4/fib_semantics.c
>> @@ -1563,13 +1563,43 @@ int fib_sync_up(struct net_device *dev, unsigned int
>> nh_flags)
>> void fib_select_multipath(struct fib_result *res, int hash)
>> {
>> struct fib_info *fi = res->fi;
>> + struct neighbour *n;
>> + int state;
>>
>> for_nexthops(fi) {
>> if (hash > atomic_read(&nh->nh_upper_bound))
>> continue;
>>
>> - res->nh_sel = nhsel;
>> - return;
>> + state = NUD_NONE;
>> + n = neigh_lookup(&arp_tbl, &nh->nh_gw, fi->fib_dev);
>> + if (n) {
>> + state = n->nud_state;
>> + neigh_release(n);
>> + }
>
> This looks like something that could use RCU to avoid expensive
> refcounting ?
Indeed, this is way too expensive as-is.
