From: David Howells Date: Mon, 4 Sep 2017 14:28:28 +0000 (+0100) Subject: rxrpc: Make service connection lookup always check for retry X-Git-Tag: v4.14-rc1~130^2~8 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=fdade4f69e4ca29753963f858dc42c5f8faf1d0b;p=platform%2Fkernel%2Flinux-rpi.git rxrpc: Make service connection lookup always check for retry When an RxRPC service packet comes in, the target connection is looked up by an rb-tree search under RCU and a read-locked seqlock; the seqlock retry check is, however, currently skipped if we got a match, but probably shouldn't be in case the connection we found gets replaced whilst we're doing a search. Make the lookup procedure always go through need_seqretry(), even if the lookup was successful. This makes sure we always pick up on a write-lock event. On the other hand, since we don't take a ref on the object, but rely on RCU to prevent its destruction after dropping the seqlock, I'm not sure this is necessary. Signed-off-by: David Howells Signed-off-by: David S. Miller --- diff --git a/net/rxrpc/conn_service.c b/net/rxrpc/conn_service.c index e60fcd2..f6fcdb3 100644 --- a/net/rxrpc/conn_service.c +++ b/net/rxrpc/conn_service.c @@ -50,12 +50,11 @@ struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *peer, else if (conn->proto.index_key > k.index_key) p = rcu_dereference_raw(p->rb_right); else - goto done; + break; conn = NULL; } } while (need_seqretry(&peer->service_conn_lock, seq)); -done: done_seqretry(&peer->service_conn_lock, seq); _leave(" = %d", conn ? conn->debug_id : -1); return conn;