ipv4: fib: Make fib_info_hashfn() return struct hlist_head.

Every time fib_info_hashfn() returns a hash value, we fetch
&fib_info_hash[hash].

Let's return the hlist_head pointer from fib_info_hashfn() and
rename it to fib_info_hash_bucket() to match a similar function,
fib_info_laddrhash_bucket().

Note that we need to move the fib_info_hash assignment earlier in
fib_info_hash_move() to use fib_info_hash_bucket() in the for loop.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250228042328.96624-5-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 9 insertions, 19 deletions

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index b7e2023bf742..54749dd7afc8 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -338,7 +338,7 @@ static unsigned int fib_info_hashfn_result(const struct net *net,
 	return hash_32(val ^ net_hash_mix(net), fib_info_hash_bits);
 }
 
-static inline unsigned int fib_info_hashfn(struct fib_info *fi)
+static struct hlist_head *fib_info_hash_bucket(struct fib_info *fi)
 {
 	unsigned int val;
 
@@ -354,7 +354,7 @@ static inline unsigned int fib_info_hashfn(struct fib_info *fi)
 		} endfor_nexthops(fi)
 	}
 
-	return fib_info_hashfn_result(fi->fib_net, val);
+	return &fib_info_hash[fib_info_hashfn_result(fi->fib_net, val)];
 }
 
 static struct hlist_head *fib_info_hash_alloc(unsigned int hash_bits)
@@ -404,12 +404,8 @@ static struct fib_info *fib_find_info_nh(struct net *net,
 
 static struct fib_info *fib_find_info(struct fib_info *nfi)
 {
-	struct hlist_head *head;
+	struct hlist_head *head = fib_info_hash_bucket(nfi);
 	struct fib_info *fi;
-	unsigned int hash;
-
-	hash = fib_info_hashfn(nfi);
-	head = &fib_info_hash[hash];
 
 	hlist_for_each_entry(fi, head, fib_hash) {
 		if (!net_eq(fi->fib_net, nfi->fib_net))
@@ -1273,22 +1269,16 @@ static void fib_info_hash_move(struct hlist_head *new_info_hash,
 	old_laddrhash = fib_info_laddrhash;
 	fib_info_hash_size = new_size;
 	fib_info_hash_bits = ilog2(new_size);
+	fib_info_hash = new_info_hash;
 
 	for (i = 0; i < old_size; i++) {
-		struct hlist_head *head = &fib_info_hash[i];
+		struct hlist_head *head = &old_info_hash[i];
 		struct hlist_node *n;
 		struct fib_info *fi;
 
-		hlist_for_each_entry_safe(fi, n, head, fib_hash) {
-			struct hlist_head *dest;
-			unsigned int new_hash;
-
-			new_hash = fib_info_hashfn(fi);
-			dest = &new_info_hash[new_hash];
-			hlist_add_head(&fi->fib_hash, dest);
-		}
+		hlist_for_each_entry_safe(fi, n, head, fib_hash)
+			hlist_add_head(&fi->fib_hash, fib_info_hash_bucket(fi));
 	}
-	fib_info_hash = new_info_hash;
 
 	fib_info_laddrhash = new_laddrhash;
 	for (i = 0; i < old_size; i++) {
@@ -1572,8 +1562,8 @@ link_it:
 	refcount_set(&fi->fib_clntref, 1);
 
 	fib_info_cnt++;
-	hlist_add_head(&fi->fib_hash,
-		       &fib_info_hash[fib_info_hashfn(fi)]);
+	hlist_add_head(&fi->fib_hash, fib_info_hash_bucket(fi));
+
 	if (fi->fib_prefsrc) {
 		struct hlist_head *head;