ipv4: remove fib_devindex_hashfn()

fib_devindex_hashfn() converts a 32bit ifindex value to a 8bit hash.

It makes no sense doing this from fib_info_hashfn() and
fib_find_info_nh().

It is better to keep as many bits as possible to let
fib_info_hashfn_result() have better spread.

Only fib_info_devhash_bucket() needs to make this operation,
we can 'inline' trivial fib_devindex_hashfn() in it.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20241004134720.579244-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 1a847ba4045876c91948bcec45cb5eccc0ef1f31..1219d1b325910322dd978f3962a4cafa8e8db10b 100644 (file)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -322,17 +322,12 @@ static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
        return 0;
 }
 
-static inline unsigned int fib_devindex_hashfn(unsigned int val)
-{
-       return hash_32(val, DEVINDEX_HASHBITS);
-}
-
 static struct hlist_head *
 fib_info_devhash_bucket(const struct net_device *dev)
 {
        u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
 
-       return &fib_info_devhash[fib_devindex_hashfn(val)];
+       return &fib_info_devhash[hash_32(val, DEVINDEX_HASHBITS)];
 }
 
 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
@@ -362,10 +357,10 @@ static inline unsigned int fib_info_hashfn(struct fib_info *fi)
                                fi->fib_priority);
 
        if (fi->nh) {
-               val ^= fib_devindex_hashfn(fi->nh->id);
+               val ^= fi->nh->id;
        } else {
                for_nexthops(fi) {
-                       val ^= fib_devindex_hashfn(nh->fib_nh_oif);
+                       val ^= nh->fib_nh_oif;
                } endfor_nexthops(fi)
        }
 
@@ -380,7 +375,7 @@ static struct fib_info *fib_find_info_nh(struct net *net,
        struct fib_info *fi;
        unsigned int hash;
 
-       hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
+       hash = fib_info_hashfn_1(cfg->fc_nh_id,
                                 cfg->fc_protocol, cfg->fc_scope,
                                 (__force u32)cfg->fc_prefsrc,
                                 cfg->fc_priority);