On Wed, Feb 10, 2016 at 7:55 PM, Bob Peterson <rpete...@redhat.com> wrote:
> This patch adds write_lock_bh locking to several places in the code
> that save and restore the socket callbacks.
>
> Signed-off-by: Bob Peterson <rpete...@redhat.com>
> ---
> fs/dlm/lowcomms.c | 35 ++++++++++++++++++++++++++---------
> 1 file changed, 26 insertions(+), 9 deletions(-)
>
> diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
> index ec5087a..4e82285 100644
> --- a/fs/dlm/lowcomms.c
> +++ b/fs/dlm/lowcomms.c
> @@ -467,10 +467,17 @@ int dlm_lowcomms_connect_node(int nodeid)
>
> static void lowcomms_error_report(struct sock *sk)
> {
> - struct connection *con = sock2con(sk);
> + struct connection *con;
> struct sockaddr_storage saddr;
> int buflen;
> + void (*orig_report)(struct sock *) = NULL;
> +
> + read_lock_bh(&sk->sk_callback_lock);
> + con = sock2con(sk);
> + if (con == NULL)
> + goto out;
>
> + orig_report = con->orig_error_report;
> if (con->sock == NULL ||
> kernel_getpeername(con->sock, (struct sockaddr *)&saddr,
> &buflen)) {
> printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
This doesn't apply cleanly to anymore, but is trivial to adapt.
> @@ -500,22 +507,29 @@ static void lowcomms_error_report(struct sock *sk)
> dlm_config.ci_tcp_port, sk->sk_err,
> sk->sk_err_soft);
> }
> - con->orig_error_report(sk);
> +out:
> + read_unlock_bh(&sk->sk_callback_lock);
> + if (orig_report)
> + orig_report(sk);
> }
>
> /* Make a socket active */
> static void add_sock(struct socket *sock, struct connection *con)
> {
> + struct sock *sk = sock->sk;
> +
> + write_lock_bh(&sk->sk_callback_lock);
> con->sock = sock;
>
> /* Install a data_ready callback */
> - con->sock->sk->sk_data_ready = lowcomms_data_ready;
> - con->sock->sk->sk_write_space = lowcomms_write_space;
> - con->sock->sk->sk_state_change = lowcomms_state_change;
> - con->sock->sk->sk_user_data = con;
> - con->sock->sk->sk_allocation = GFP_NOFS;
> - con->orig_error_report = con->sock->sk->sk_error_report;
> - con->sock->sk->sk_error_report = lowcomms_error_report;
> + sk->sk_data_ready = lowcomms_data_ready;
> + sk->sk_write_space = lowcomms_write_space;
> + sk->sk_state_change = lowcomms_state_change;
> + sk->sk_user_data = con;
> + sk->sk_allocation = GFP_NOFS;
> + con->orig_error_report = sk->sk_error_report;
> + sk->sk_error_report = lowcomms_error_report;
> + write_unlock_bh(&sk->sk_callback_lock);
> }
>
> /* Add the port number to an IPv6 or 4 sockaddr and return the address
> @@ -1274,6 +1288,7 @@ static int sctp_listen_for_all(void)
> if (result < 0)
> log_print("Could not set SCTP NODELAY error %d\n", result);
>
> + write_lock_bh(&sock->sk->sk_callback_lock);
> /* Init con struct */
> sock->sk->sk_user_data = con;
> con->sock = sock;
> @@ -1281,6 +1296,8 @@ static int sctp_listen_for_all(void)
> con->rx_action = sctp_accept_from_sock;
> con->connect_action = sctp_connect_to_sock;
>
> + write_unlock_bh(&sock->sk->sk_callback_lock);
> +
> /* Bind to all addresses. */
> if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))
> goto create_delsock;
> --
> 2.5.0
>
Reviewed-by: Andreas Gruenbacher <agrue...@redhat.com>
