rxrpc: Allow listen(sock, 0) to be used to disable listening

Allow listen() with a backlog of 0 to be used to disable listening on an
AF_RXRPC socket.  This also releases any preallocation, thereby making it
easier for a kernel service to account for all allocated call structures
when shutting down the service.

The socket cannot thereafter have listening reenabled, but must rather be
closed and reopened.

Signed-off-by: David Howells <dhowells@redhat.com>

diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index 5f63f6d..199b46e 100644 (file)
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -224,6 +224,14 @@ static int rxrpc_listen(struct socket *sock, int backlog)
                else
                        sk->sk_max_ack_backlog = old;
                break;
+       case RXRPC_SERVER_LISTENING:
+               if (backlog == 0) {
+                       rx->sk.sk_state = RXRPC_SERVER_LISTEN_DISABLED;
+                       sk->sk_max_ack_backlog = 0;
+                       rxrpc_discard_prealloc(rx);
+                       ret = 0;
+                       break;
+               }
        default:
                ret = -EBUSY;
                break;

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 84927c7..12be432 100644 (file)
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -60,6 +60,7 @@ enum {
        RXRPC_CLIENT_BOUND,             /* client local address bound */
        RXRPC_SERVER_BOUND,             /* server local address bound */
        RXRPC_SERVER_LISTENING,         /* server listening for connections */
+       RXRPC_SERVER_LISTEN_DISABLED,   /* server listening disabled */
        RXRPC_CLOSE,                    /* socket is being closed */
 };
 

diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index 832d854..7c4c64a 100644 (file)
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -349,7 +349,8 @@ struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
 
 found_service:
        spin_lock(&rx->incoming_lock);
-       if (rx->sk.sk_state == RXRPC_CLOSE) {
+       if (rx->sk.sk_state == RXRPC_SERVER_LISTEN_DISABLED ||
+           rx->sk.sk_state == RXRPC_CLOSE) {
                trace_rxrpc_abort("CLS", sp->hdr.cid, sp->hdr.callNumber,
                                  sp->hdr.seq, RX_INVALID_OPERATION, ESHUTDOWN);
                skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;