diff options
| author | Paolo Abeni <pabeni@redhat.com> | 2020-02-28 14:45:21 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-28 12:12:53 -0800 |
| commit | 7782040b950b5d0433f734fb2bba8b8b5ed6ce5a (patch) | |
| tree | 70d2549b3467bf6ec5b3e96d7d679e111d1b984c /net/unix | |
| parent | e955376277839db92774ec24d559ab42442b95fc (diff) | |
| download | lwn-7782040b950b5d0433f734fb2bba8b8b5ed6ce5a.tar.gz lwn-7782040b950b5d0433f734fb2bba8b8b5ed6ce5a.zip | |
unix: uses an atomic type for scm files accounting
So the scm_stat_{add,del} helper can be invoked with no
additional lock held.
This clean-up the code a bit and will make the next
patch easier.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/unix')
| -rw-r--r-- | net/unix/af_unix.c | 21 |
1 files changed, 6 insertions, 15 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 9d0518d9bdd4..c46fa271fc4a 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -690,7 +690,8 @@ static void unix_show_fdinfo(struct seq_file *m, struct socket *sock) if (sk) { u = unix_sk(sock->sk); - seq_printf(m, "scm_fds: %u\n", READ_ONCE(u->scm_stat.nr_fds)); + seq_printf(m, "scm_fds: %u\n", + atomic_read(&u->scm_stat.nr_fds)); } } #else @@ -1602,10 +1603,8 @@ static void scm_stat_add(struct sock *sk, struct sk_buff *skb) struct scm_fp_list *fp = UNIXCB(skb).fp; struct unix_sock *u = unix_sk(sk); - lockdep_assert_held(&sk->sk_receive_queue.lock); - if (unlikely(fp && fp->count)) - u->scm_stat.nr_fds += fp->count; + atomic_add(fp->count, &u->scm_stat.nr_fds); } static void scm_stat_del(struct sock *sk, struct sk_buff *skb) @@ -1613,10 +1612,8 @@ static void scm_stat_del(struct sock *sk, struct sk_buff *skb) struct scm_fp_list *fp = UNIXCB(skb).fp; struct unix_sock *u = unix_sk(sk); - lockdep_assert_held(&sk->sk_receive_queue.lock); - if (unlikely(fp && fp->count)) - u->scm_stat.nr_fds -= fp->count; + atomic_sub(fp->count, &u->scm_stat.nr_fds); } /* @@ -1805,10 +1802,8 @@ restart_locked: if (sock_flag(other, SOCK_RCVTSTAMP)) __net_timestamp(skb); maybe_add_creds(skb, sock, other); - spin_lock(&other->sk_receive_queue.lock); scm_stat_add(other, skb); - __skb_queue_tail(&other->sk_receive_queue, skb); - spin_unlock(&other->sk_receive_queue.lock); + skb_queue_tail(&other->sk_receive_queue, skb); unix_state_unlock(other); other->sk_data_ready(other); sock_put(other); @@ -1910,10 +1905,8 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, goto pipe_err_free; maybe_add_creds(skb, sock, other); - spin_lock(&other->sk_receive_queue.lock); scm_stat_add(other, skb); - __skb_queue_tail(&other->sk_receive_queue, skb); - spin_unlock(&other->sk_receive_queue.lock); + skb_queue_tail(&other->sk_receive_queue, skb); unix_state_unlock(other); other->sk_data_ready(other); sent += size; @@ -2409,9 +2402,7 @@ unlock: sk_peek_offset_bwd(sk, chunk); if (UNIXCB(skb).fp) { - spin_lock(&sk->sk_receive_queue.lock); scm_stat_del(sk, skb); - spin_unlock(&sk->sk_receive_queue.lock); unix_detach_fds(&scm, skb); } |