Re: [PATCH 27/33] sctp: export sctp_setsockopt_bindx

From: Marcelo Ricardo Leitner
Date: Wed May 13 2020 - 14:01:06 EST


On Wed, May 13, 2020 at 08:26:42AM +0200, Christoph Hellwig wrote:
> And call it directly from dlm instead of going through kernel_setsockopt.

The advantage on using kernel_setsockopt here is that sctp module will
only be loaded if dlm actually creates a SCTP socket. With this
change, sctp will be loaded on setups that may not be actually using
it. It's a quite big module and might expose the system.

I'm okay with the SCTP changes, but I'll defer to DLM folks to whether
that's too bad or what for DLM.

>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/dlm/lowcomms.c | 13 ++++++++-----
> include/net/sctp/sctp.h | 3 +++
> net/sctp/socket.c | 5 +++--
> 3 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
> index b722a09a7ca05..e4939d770df53 100644
> --- a/fs/dlm/lowcomms.c
> +++ b/fs/dlm/lowcomms.c
> @@ -1005,14 +1005,17 @@ static int sctp_bind_addrs(struct connection *con, uint16_t port)
> memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
> make_sockaddr(&localaddr, port, &addr_len);
>
> - if (!i)
> + if (!i) {
> result = kernel_bind(con->sock,
> (struct sockaddr *)&localaddr,
> addr_len);
> - else
> - result = kernel_setsockopt(con->sock, SOL_SCTP,
> - SCTP_SOCKOPT_BINDX_ADD,
> - (char *)&localaddr, addr_len);
> + } else {
> + lock_sock(con->sock->sk);
> + result = sctp_setsockopt_bindx(con->sock->sk,
> + (struct sockaddr *)&localaddr, addr_len,
> + SCTP_BINDX_ADD_ADDR);
> + release_sock(con->sock->sk);
> + }
>
> if (result < 0) {
> log_print("Can't bind to %d addr number %d, %d.\n",
> diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
> index 3ab5c6bbb90bd..f702b14d768ba 100644
> --- a/include/net/sctp/sctp.h
> +++ b/include/net/sctp/sctp.h
> @@ -615,4 +615,7 @@ static inline bool sctp_newsk_ready(const struct sock *sk)
> return sock_flag(sk, SOCK_DEAD) || sk->sk_socket;
> }
>
> +int sctp_setsockopt_bindx(struct sock *sk, struct sockaddr *kaddrs,
> + int addrs_size, int op);
> +
> #endif /* __net_sctp_h__ */
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 1c96b52c4aa28..30c981d9f6158 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -979,8 +979,8 @@ int sctp_asconf_mgmt(struct sctp_sock *sp, struct sctp_sockaddr_entry *addrw)
> *
> * Returns 0 if ok, <0 errno code on error.
> */
> -static int sctp_setsockopt_bindx(struct sock *sk, struct sockaddr *kaddrs,
> - int addrs_size, int op)
> +int sctp_setsockopt_bindx(struct sock *sk, struct sockaddr *kaddrs,
> + int addrs_size, int op)
> {
> int err;
> int addrcnt = 0;
> @@ -1032,6 +1032,7 @@ static int sctp_setsockopt_bindx(struct sock *sk, struct sockaddr *kaddrs,
> return -EINVAL;
> }
> }
> +EXPORT_SYMBOL(sctp_setsockopt_bindx);
>
> static int sctp_connect_new_asoc(struct sctp_endpoint *ep,
> const union sctp_addr *daddr,
> --
> 2.26.2
>