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 <dhowells@redhat.com>

1 files changed, 0 insertions, 17 deletions

diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c
index 70083e8fb6e5..01a9febfa367 100644
--- a/net/rxrpc/peer_object.c
+++ b/net/rxrpc/peer_object.c
@@ -220,8 +220,6 @@ struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
 		atomic_set(&peer->usage, 1);
 		peer->local = local;
 		INIT_HLIST_HEAD(&peer->error_targets);
-		INIT_WORK(&peer->error_distributor,
-			  &rxrpc_peer_error_distributor);
 		peer->service_conns = RB_ROOT;
 		seqlock_init(&peer->service_conn_lock);
 		spin_lock_init(&peer->lock);
@@ -403,21 +401,6 @@ struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
 }
 
 /*
- * Queue a peer record.  This passes the caller's ref to the workqueue.
- */
-void __rxrpc_queue_peer_error(struct rxrpc_peer *peer)
-{
-	const void *here = __builtin_return_address(0);
-	int n;
-
-	n = atomic_read(&peer->usage);
-	if (rxrpc_queue_work(&peer->error_distributor))
-		trace_rxrpc_peer(peer, rxrpc_peer_queued_error, n, here);
-	else
-		rxrpc_put_peer(peer);
-}
-
-/*
  * Discard a peer record.
  */
 static void __rxrpc_put_peer(struct rxrpc_peer *peer)