Commit b79bcaf7 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

ipv4: fib: Add fib_info_hash_grow(). 



When the number of struct fib_info exceeds the hash table size in
fib_create_info(), we try to allocate a new hash table with the
doubled size.

The allocation is done in fib_create_info(), and if successful, each
struct fib_info is moved to the new hash table by fib_info_hash_move().

Let's integrate the allocation and fib_info_hash_move() as
fib_info_hash_grow() to make the following change cleaner.

While at it, fib_info_hash_grow() is placed near other hash-table-specific
functions.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250228042328.96624-8-kuniyu@amazon.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent d6306b9d

net/ipv4/fib_semantics.c

+41 −44
Original line number Diff line number Diff line
@@ -376,6 +376,46 @@ static void fib_info_hash_free(struct hlist_head *head) 
	kvfree(head);

}



static void fib_info_hash_grow(void)

{

	struct hlist_head *new_info_hash, *old_info_hash;

	unsigned int old_size = 1 << fib_info_hash_bits;

	unsigned int i;



	if (fib_info_cnt < old_size)

		return;



	new_info_hash = fib_info_hash_alloc(fib_info_hash_bits + 1);

	if (!new_info_hash)

		return;



	old_info_hash = fib_info_hash;

	fib_info_hash = new_info_hash;

	fib_info_hash_bits += 1;



	for (i = 0; i < old_size; 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)

			hlist_add_head(&fi->fib_hash, fib_info_hash_bucket(fi));

	}



	for (i = 0; i < old_size; i++) {

		struct hlist_head *lhead = &old_info_hash[old_size + i];

		struct hlist_node *n;

		struct fib_info *fi;



		hlist_for_each_entry_safe(fi, n, lhead, fib_lhash)

			hlist_add_head(&fi->fib_lhash,

				       fib_info_laddrhash_bucket(fi->fib_net,

								 fi->fib_prefsrc));

	}



	fib_info_hash_free(old_info_hash);

}



/* no metrics, only nexthop id */

static struct fib_info *fib_find_info_nh(struct net *net,

					 const struct fib_config *cfg)
@@ -1254,43 +1294,6 @@ int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 
	return err;

}



static void fib_info_hash_move(struct hlist_head *new_info_hash)

{

	unsigned int old_size = 1 << fib_info_hash_bits;

	struct hlist_head *old_info_hash;

	unsigned int i;



	ASSERT_RTNL();

	old_info_hash = fib_info_hash;

	fib_info_hash_bits += 1;

	fib_info_hash = new_info_hash;



	for (i = 0; i < old_size; 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)

			hlist_add_head(&fi->fib_hash, fib_info_hash_bucket(fi));

	}



	for (i = 0; i < old_size; i++) {

		struct hlist_head *lhead = &old_info_hash[old_size + i];

		struct hlist_node *n;

		struct fib_info *fi;



		hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {

			struct hlist_head *ldest;



			ldest = fib_info_laddrhash_bucket(fi->fib_net,

							  fi->fib_prefsrc);

			hlist_add_head(&fi->fib_lhash, ldest);

		}

	}



	fib_info_hash_free(old_info_hash);

}



__be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,

				 unsigned char scope)

{
@@ -1403,13 +1406,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg, 
	}

#endif



	if (fib_info_cnt >= (1 << fib_info_hash_bits)) {

		struct hlist_head *new_info_hash;



		new_info_hash = fib_info_hash_alloc(fib_info_hash_bits + 1);

		if (new_info_hash)

			fib_info_hash_move(new_info_hash);

	}

	fib_info_hash_grow();



	fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);

	if (!fi) {