net: get rid of rtable->idev

It seems idev field in struct rtable has no special purpose, but adding
extra atomic ops.

We hold refcounts on the device itself (using percpu data, so pretty
cheap in current kernel).

infiniband case is solved using dst.dev instead of idev->dev

Removal of this field means routing without route cache is now using
shared data, percpu data, and only potential contention is a pair of
atomic ops on struct neighbour per forwarded packet.

About 5% speedup on routing test.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c
index a5ea1bce968..c15fd2ea56c 100644
--- a/drivers/infiniband/core/addr.c
+++ b/drivers/infiniband/core/addr.c
@@ -200,7 +200,7 @@ static int addr4_resolve(struct sockaddr_in *src_in,
         src_in->sin_family = AF_INET;
         src_in->sin_addr.s_addr = rt->rt_src;
 
-        if (rt->idev->dev->flags & IFF_LOOPBACK) {
+        if (rt->dst.dev->flags & IFF_LOOPBACK) {
                 ret = rdma_translate_ip((struct sockaddr *) dst_in, addr);
                 if (!ret)
                         memcpy(addr->dst_dev_addr, addr->src_dev_addr, MAX_ADDR_LEN);
@@ -208,12 +208,12 @@ static int addr4_resolve(struct sockaddr_in *src_in,
         }
 
         /* If the device does ARP internally, return 'done' */
-        if (rt->idev->dev->flags & IFF_NOARP) {
-                rdma_copy_addr(addr, rt->idev->dev, NULL);
+        if (rt->dst.dev->flags & IFF_NOARP) {
+                rdma_copy_addr(addr, rt->dst.dev, NULL);
                 goto put;
         }
 
-        neigh = neigh_lookup(&arp_tbl, &rt->rt_gateway, rt->idev->dev);
+        neigh = neigh_lookup(&arp_tbl, &rt->rt_gateway, rt->dst.dev);
         if (!neigh || !(neigh->nud_state & NUD_VALID)) {
                 neigh_event_send(rt->dst.neighbour, NULL);
                 ret = -ENODATA;