net neigh: RCU conversion of neigh hash table

David

This is the first step for RCU conversion of neigh code.

Next patches will convert hash_buckets[] and "struct neighbour" to RCU
protected objects.

Thanks

[PATCH net-next] net neigh: RCU conversion of neigh hash table

Instead of storing hash_buckets, hash_mask and hash_rnd in "struct
neigh_table", a new structure is defined :

struct neigh_hash_table {
       struct neighbour        **hash_buckets;
       unsigned int            hash_mask;
       __u32                   hash_rnd;
       struct rcu_head         rcu;
};

And "struct neigh_table" has an RCU protected pointer to such a
neigh_hash_table.

This means the signature of (*hash)() function changed: We need to add a
third parameter with the actual hash_rnd value, since this is not
anymore a neigh_table field.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 3 deletions

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index d9031ad67826..f35309578170 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -127,7 +127,7 @@ EXPORT_SYMBOL(clip_tbl_hook);
 /*
  *      Interface to generic neighbour cache.
  */
-static u32 arp_hash(const void *pkey, const struct net_device *dev);
+static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 rnd);
 static int arp_constructor(struct neighbour *neigh);
 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
@@ -225,9 +225,11 @@ int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
 }
 
 
-static u32 arp_hash(const void *pkey, const struct net_device *dev)
+static u32 arp_hash(const void *pkey,
+                    const struct net_device *dev,
+                    __u32 hash_rnd)
 {
-        return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd);
+        return jhash_2words(*(u32 *)pkey, dev->ifindex, hash_rnd);
 }
 
 static int arp_constructor(struct neighbour *neigh)