| Message ID | 20190503155501.28182-1-dsahern@kernel.org |
|---|---|
| State | Changes Requested |
| Delegated to: | David Miller |
| Headers | show |
| Series | [v2,net] neighbor: Call __ipv4_neigh_lookup_noref in neigh_xmit | expand |
From: David Ahern <dsahern@kernel.org> Date: Fri, 3 May 2019 08:55:01 -0700 > From: David Ahern <dsahern@gmail.com> > > Commit cd9ff4de0107 changed the key for IFF_POINTOPOINT devices to > INADDR_ANY, but neigh_xmit which is used for MPLS encapsulations was not > updated to use the altered key. The result is that every packet Tx does > a lookup on the gateway address which does not find an entry, a new one > is created only to find the existing one in the table right before the > insert since arp_constructor was updated to reset the primary key. This > is seen in the allocs and destroys counters: > ip -s -4 ntable show | head -10 | grep alloc > > which increase for each packet showing the unnecessary overhread. > > Fix by having neigh_xmit use __ipv4_neigh_lookup_noref for NEIGH_ARP_TABLE. > Define __ipv4_neigh_lookup_noref in case CONFIG_INET is not set. > > v2 > - define __ipv4_neigh_lookup_noref in case CONFIG_INET is not set as > reported by kbuild test robot > > Fixes: cd9ff4de0107 ("ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY") > Reported-by: Alan Maguire <alan.maguire@oracle.com> > Signed-off-by: David Ahern <dsahern@gmail.com> > > Signed-off-by: David Ahern <dsahern@gmail.com> Double signoff and this patch doesn't apply to the net tree.
On 5/5/19 11:42 AM, David Miller wrote: > From: David Ahern <dsahern@kernel.org> > Date: Fri, 3 May 2019 08:55:01 -0700 > >> From: David Ahern <dsahern@gmail.com> >> >> Commit cd9ff4de0107 changed the key for IFF_POINTOPOINT devices to >> INADDR_ANY, but neigh_xmit which is used for MPLS encapsulations was not >> updated to use the altered key. The result is that every packet Tx does >> a lookup on the gateway address which does not find an entry, a new one >> is created only to find the existing one in the table right before the >> insert since arp_constructor was updated to reset the primary key. This >> is seen in the allocs and destroys counters: >> ip -s -4 ntable show | head -10 | grep alloc >> >> which increase for each packet showing the unnecessary overhread. >> >> Fix by having neigh_xmit use __ipv4_neigh_lookup_noref for NEIGH_ARP_TABLE. >> Define __ipv4_neigh_lookup_noref in case CONFIG_INET is not set. >> >> v2 >> - define __ipv4_neigh_lookup_noref in case CONFIG_INET is not set as >> reported by kbuild test robot >> >> Fixes: cd9ff4de0107 ("ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY") >> Reported-by: Alan Maguire <alan.maguire@oracle.com> >> Signed-off-by: David Ahern <dsahern@gmail.com> >> >> Signed-off-by: David Ahern <dsahern@gmail.com> > > Double signoff and this patch doesn't apply to the net tree. > oops on the double signoff; you actually took v1 so I need to send a delta.
From: David Ahern <dsahern@gmail.com> Date: Sun, 5 May 2019 11:43:39 -0600 > oops on the double signoff; you actually took v1 so I need to send a delta. Aha, I see, thanks for catching that.
diff --git a/include/net/arp.h b/include/net/arp.h index 977aabfcdc03..c8f580a0e6b1 100644 --- a/include/net/arp.h +++ b/include/net/arp.h @@ -18,6 +18,7 @@ static inline u32 arp_hashfn(const void *pkey, const struct net_device *dev, u32 return val * hash_rnd[0]; } +#ifdef CONFIG_INET static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key) { if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) @@ -25,6 +26,13 @@ static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev return ___neigh_lookup_noref(&arp_tbl, neigh_key_eq32, arp_hashfn, &key, dev); } +#else +static inline +struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key) +{ + return NULL; +} +#endif static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key) { diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 30f6fd8f68e0..0ba5018ccb7f 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -31,6 +31,7 @@ #include <linux/times.h> #include <net/net_namespace.h> #include <net/neighbour.h> +#include <net/arp.h> #include <net/dst.h> #include <net/sock.h> #include <net/netevent.h> @@ -2982,7 +2983,13 @@ int neigh_xmit(int index, struct net_device *dev, if (!tbl) goto out; rcu_read_lock_bh(); - neigh = __neigh_lookup_noref(tbl, addr, dev); + if (index == NEIGH_ARP_TABLE) { + u32 key = *((u32 *)addr); + + neigh = __ipv4_neigh_lookup_noref(dev, key); + } else { + neigh = __neigh_lookup_noref(tbl, addr, dev); + } if (!neigh) neigh = __neigh_create(tbl, addr, dev, false); err = PTR_ERR(neigh);