Commit d40ce48c authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'af_unix-replace-unix_table_lock-with-per-hash-locks' 

Kuniyuki Iwashima says:

====================
af_unix: Replace unix_table_lock with per-hash locks.

The hash table of AF_UNIX sockets is protected by a single big lock,
unix_table_lock.  This series replaces it with small per-hash locks.

1st -  2nd : Misc refactoring
3rd -  8th : Separate BSD/abstract address logics
9th - 11th : Prep to save a hash in each socket
12th       : Replace the big lock
13th       : Speed up autobind()

Note to maintainers:
The 12th patch adds two kinds of Sparse warnings on patchwork:

  about unix_table_double_lock/unlock()
    We can avoid this by adding two apparent acquires/releases annotations,
    but there are the same kinds of warnings about unix_state_double_lock().

  about unix_next_socket() and unix_seq_stop() (/proc/net/unix)
    This is because Sparse does not understand logic in unix_next_socket(),
    which leaves a spin lock held until it returns NULL.
    Also, tcp_seq_stop() causes a warning for the same reason.

These warnings seem reasonable, but let me know if there is any better way.
Please see [0] for details.

[0]: https://lore.kernel.org/netdev/20211117001611.74123-1-kuniyu@amazon.co.jp/
====================

Link: https://lore.kernel.org/r/20211124021431.48956-1-kuniyu@amazon.co.jp


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 442b03c3 9acbc584

include/net/af_unix.h

+1 −2
Original line number Diff line number Diff line
@@ -20,13 +20,12 @@ struct sock *unix_peer_get(struct sock *sk); 
#define UNIX_HASH_BITS	8



extern unsigned int unix_tot_inflight;

extern spinlock_t unix_table_lock;

extern spinlock_t unix_table_locks[2 * UNIX_HASH_SIZE];

extern struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];



struct unix_address {

	refcount_t	refcnt;

	int		len;

	unsigned int	hash;

	struct sockaddr_un name[];

};

net/unix/af_unix.c

+331 −236

File changed.

Preview size limit exceeded, changes collapsed.

net/unix/diag.c

+12 −11
Original line number Diff line number Diff line
@@ -13,13 +13,14 @@ 


static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb)

{

	/* might or might not have unix_table_lock */

	/* might or might not have unix_table_locks */

	struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);



	if (!addr)

		return 0;



	return nla_put(nlskb, UNIX_DIAG_NAME, addr->len - sizeof(short),

	return nla_put(nlskb, UNIX_DIAG_NAME,

		       addr->len - offsetof(struct sockaddr_un, sun_path),

		       addr->name->sun_path);

}
@@ -203,13 +204,13 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb) 
	s_slot = cb->args[0];

	num = s_num = cb->args[1];



	spin_lock(&unix_table_lock);

	for (slot = s_slot;

	     slot < ARRAY_SIZE(unix_socket_table);

	     s_num = 0, slot++) {

		struct sock *sk;



		num = 0;

		spin_lock(&unix_table_locks[slot]);

		sk_for_each(sk, &unix_socket_table[slot]) {

			if (!net_eq(sock_net(sk), net))

				continue;
@@ -220,14 +221,16 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb) 
			if (sk_diag_dump(sk, skb, req,

					 NETLINK_CB(cb->skb).portid,

					 cb->nlh->nlmsg_seq,

					 NLM_F_MULTI) < 0)

					 NLM_F_MULTI) < 0) {

				spin_unlock(&unix_table_locks[slot]);

				goto done;

			}

next:

			num++;

		}

		spin_unlock(&unix_table_locks[slot]);

	}

done:

	spin_unlock(&unix_table_lock);

	cb->args[0] = slot;

	cb->args[1] = num;
@@ -236,21 +239,19 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb) 


static struct sock *unix_lookup_by_ino(unsigned int ino)

{

	int i;

	struct sock *sk;

	int i;



	spin_lock(&unix_table_lock);

	for (i = 0; i < ARRAY_SIZE(unix_socket_table); i++) {

		spin_lock(&unix_table_locks[i]);

		sk_for_each(sk, &unix_socket_table[i])

			if (ino == sock_i_ino(sk)) {

				sock_hold(sk);

				spin_unlock(&unix_table_lock);



				spin_unlock(&unix_table_locks[i]);

				return sk;

			}

		spin_unlock(&unix_table_locks[i]);

	}



	spin_unlock(&unix_table_lock);

	return NULL;

}

tools/testing/selftests/bpf/progs/bpf_iter_unix.c

+1 −1
Original line number Diff line number Diff line
@@ -49,7 +49,7 @@ int dump_unix(struct bpf_iter__unix *ctx) 
		       sock_i_ino(sk));



	if (unix_sk->addr) {

		if (!UNIX_ABSTRACT(unix_sk)) {

		if (unix_sk->addr->name->sun_path[0]) {

			BPF_SEQ_PRINTF(seq, " %s", unix_sk->addr->name->sun_path);

		} else {

			/* The name of the abstract UNIX domain socket starts

tools/testing/selftests/bpf/progs/bpf_tracing_net.h

+0 −2

File changed.

Preview size limit exceeded, changes collapsed.