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, 7 insertions, 3 deletions

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index b3dd844cd34f..998d6d27e7cf 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -91,7 +91,9 @@
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv6.h>
 
-static u32 ndisc_hash(const void *pkey, const struct net_device *dev);
+static u32 ndisc_hash(const void *pkey,
+                      const struct net_device *dev,
+                      __u32 rnd);
 static int ndisc_constructor(struct neighbour *neigh);
 static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb);
 static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb);
@@ -350,7 +352,9 @@ int ndisc_mc_map(struct in6_addr *addr, char *buf, struct net_device *dev, int d
 
 EXPORT_SYMBOL(ndisc_mc_map);
 
-static u32 ndisc_hash(const void *pkey, const struct net_device *dev)
+static u32 ndisc_hash(const void *pkey,
+                      const struct net_device *dev,
+                      __u32 hash_rnd)
 {
         const u32 *p32 = pkey;
         u32 addr_hash, i;
@@ -359,7 +363,7 @@ static u32 ndisc_hash(const void *pkey, const struct net_device *dev)
         for (i = 0; i < (sizeof(struct in6_addr) / sizeof(u32)); i++)
                 addr_hash ^= *p32++;
 
-        return jhash_2words(addr_hash, dev->ifindex, nd_tbl.hash_rnd);
+        return jhash_2words(addr_hash, dev->ifindex, hash_rnd);
 }
 
 static int ndisc_constructor(struct neighbour *neigh)