From f334430316e7fd37c4821ebec627e27714bb5d76 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 27 Sep 2018 15:13:09 +0100 Subject: rxrpc: Fix error distribution Fix error distribution by immediately delivering the errors to all the affected calls rather than deferring them to a worker thread. The problem with the latter is that retries and things can happen in the meantime when we want to stop that sooner. To this end: (1) Stop the error distributor from removing calls from the error_targets list so that peer->lock isn't needed to synchronise against other adds and removals. (2) Require the peer's error_targets list to be accessed with RCU, thereby avoiding the need to take peer->lock over distribution. (3) Don't attempt to affect a call's state if it is already marked complete. Signed-off-by: David Howells --- net/rxrpc/peer_event.c | 46 +++++++++++----------------------------------- 1 file changed, 11 insertions(+), 35 deletions(-) (limited to 'net/rxrpc/peer_event.c') diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c index 4f9da2f51c69..f3e6fc670da2 100644 --- a/net/rxrpc/peer_event.c +++ b/net/rxrpc/peer_event.c @@ -23,6 +23,8 @@ #include "ar-internal.h" static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *); +static void rxrpc_distribute_error(struct rxrpc_peer *, int, + enum rxrpc_call_completion); /* * Find the peer associated with an ICMP packet. @@ -194,8 +196,6 @@ void rxrpc_error_report(struct sock *sk) rcu_read_unlock(); rxrpc_free_skb(skb, rxrpc_skb_rx_freed); - /* The ref we obtained is passed off to the work item */ - __rxrpc_queue_peer_error(peer); _leave(""); } @@ -205,6 +205,7 @@ void rxrpc_error_report(struct sock *sk) static void rxrpc_store_error(struct rxrpc_peer *peer, struct sock_exterr_skb *serr) { + enum rxrpc_call_completion compl = RXRPC_CALL_NETWORK_ERROR; struct sock_extended_err *ee; int err; @@ -255,7 +256,7 @@ static void rxrpc_store_error(struct rxrpc_peer *peer, case SO_EE_ORIGIN_NONE: case SO_EE_ORIGIN_LOCAL: _proto("Rx Received local error { error=%d }", err); - err += RXRPC_LOCAL_ERROR_OFFSET; + compl = RXRPC_CALL_LOCAL_ERROR; break; case SO_EE_ORIGIN_ICMP6: @@ -264,48 +265,23 @@ static void rxrpc_store_error(struct rxrpc_peer *peer, break; } - peer->error_report = err; + rxrpc_distribute_error(peer, err, compl); } /* - * Distribute an error that occurred on a peer + * Distribute an error that occurred on a peer. */ -void rxrpc_peer_error_distributor(struct work_struct *work) +static void rxrpc_distribute_error(struct rxrpc_peer *peer, int error, + enum rxrpc_call_completion compl) { - struct rxrpc_peer *peer = - container_of(work, struct rxrpc_peer, error_distributor); struct rxrpc_call *call; - enum rxrpc_call_completion compl; - int error; - - _enter(""); - - error = READ_ONCE(peer->error_report); - if (error < RXRPC_LOCAL_ERROR_OFFSET) { - compl = RXRPC_CALL_NETWORK_ERROR; - } else { - compl = RXRPC_CALL_LOCAL_ERROR; - error -= RXRPC_LOCAL_ERROR_OFFSET; - } - _debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error); - - spin_lock_bh(&peer->lock); - - while (!hlist_empty(&peer->error_targets)) { - call = hlist_entry(peer->error_targets.first, - struct rxrpc_call, error_link); - hlist_del_init(&call->error_link); + hlist_for_each_entry_rcu(call, &peer->error_targets, error_link) { rxrpc_see_call(call); - - if (rxrpc_set_call_completion(call, compl, 0, -error)) + if (call->state < RXRPC_CALL_COMPLETE && + rxrpc_set_call_completion(call, compl, 0, -error)) rxrpc_notify_socket(call); } - - spin_unlock_bh(&peer->lock); - - rxrpc_put_peer(peer); - _leave(""); } /* -- cgit v1.2.3