rxrpc: Move usage count getting into rxrpc_queue_conn()

Rather than calling rxrpc_get_connection() manually before calling
rxrpc_queue_conn(), do it inside the queue wrapper.

This allows us to do some important fixes:

 (1) If the usage count is 0, do nothing.  This prevents connections from
     being reanimated once they're dead.

 (2) If rxrpc_queue_work() fails because the work item is already queued,
     retract the usage count increment which would otherwise be lost.

 (3) Don't take a ref on the connection in the work function.  By passing
     the ref through the work item, this is unnecessary.  Doing it in the
     work function is too late anyway.  Previously, connection-directed
     packets held a ref on the connection, but that's not really the best
     idea.

And another useful changes:

 (*) Don't need to take a refcount on the connection in the data_ready
     handler unless we invoke the connection's work item.  We're using RCU
     there so that's otherwise redundant.

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

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 6583a8399c893ca332c9d004b6f8dd3a1d38580f..9fc89cdc6ae3e283d51ecda13ad83fe2240504fb 100644 (file)
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -584,10 +584,17 @@ static inline void rxrpc_get_connection(struct rxrpc_connection *conn)
        atomic_inc(&conn->usage);
 }
 
+static inline
+struct rxrpc_connection *rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
+{
+       return atomic_inc_not_zero(&conn->usage) ? conn : NULL;
+}
 
 static inline void rxrpc_queue_conn(struct rxrpc_connection *conn)
 {
-       rxrpc_queue_work(&conn->processor);
+       if (rxrpc_get_connection_maybe(conn) &&
+           !rxrpc_queue_work(&conn->processor))
+               rxrpc_put_connection(conn);
 }
 
 /*

diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index 1c0860df150e4c710d75b29155a1a657223e388d..5367dbe9b96f1783d910378b5cf9eaba52872285 100644 (file)
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -132,7 +132,6 @@ static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
                        _debug("await conn sec");
                        list_add_tail(&call->accept_link, &rx->secureq);
                        call->conn->state = RXRPC_CONN_SERVICE_CHALLENGING;
-                       rxrpc_get_connection(call->conn);
                        set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events);
                        rxrpc_queue_conn(call->conn);
                } else {

diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index b9c39b83eddbd547026b4bdff30133b8d5010a27..9ceddd3fd5dbe30fb826ffa94ae558e8103fa0d1 100644 (file)
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -266,12 +266,8 @@ void rxrpc_process_connection(struct work_struct *work)
 
        _enter("{%d}", conn->debug_id);
 
-       rxrpc_get_connection(conn);
-
-       if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events)) {
+       if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events))
                rxrpc_secure_connection(conn);
-               rxrpc_put_connection(conn);
-       }
 
        /* go through the conn-level event packets, releasing the ref on this
         * connection that each one has when we've finished with it */
@@ -286,7 +282,6 @@ void rxrpc_process_connection(struct work_struct *work)
                        goto requeue_and_leave;
                case -ECONNABORTED:
                default:
-                       rxrpc_put_connection(conn);
                        rxrpc_free_skb(skb);
                        break;
                }
@@ -304,7 +299,6 @@ requeue_and_leave:
 protocol_error:
        if (rxrpc_abort_connection(conn, -ret, abort_code) < 0)
                goto requeue_and_leave;
-       rxrpc_put_connection(conn);
        rxrpc_free_skb(skb);
        _leave(" [EPROTO]");
        goto out;

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index fe7ff339d7e500321a8a7d04aab006127990c461..b993f2dc5a09c736eaa48c2568769f2ce7290022 100644 (file)
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -580,7 +580,6 @@ static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 {
        _enter("%p,%p", conn, skb);
 
-       rxrpc_get_connection(conn);
        skb_queue_tail(&conn->rx_queue, skb);
        rxrpc_queue_conn(conn);
 }