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authorDavid Howells <dhowells@redhat.com>2018-09-27 15:13:09 +0100
committerDavid Howells <dhowells@redhat.com>2018-09-28 10:33:17 +0100
commitf334430316e7fd37c4821ebec627e27714bb5d76 (patch)
treea8e7fb558d409f5a36ba8104975272ed91b5ab9a /net/rxrpc
parent37a675e768d7606fe8a53e0c459c9b53e121ac20 (diff)
downloadlinux-stericsson-f334430316e7fd37c4821ebec627e27714bb5d76.tar.gz
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>
Diffstat (limited to 'net/rxrpc')
-rw-r--r--net/rxrpc/ar-internal.h5
-rw-r--r--net/rxrpc/call_object.c2
-rw-r--r--net/rxrpc/conn_client.c4
-rw-r--r--net/rxrpc/conn_object.c2
-rw-r--r--net/rxrpc/peer_event.c46
-rw-r--r--net/rxrpc/peer_object.c17
6 files changed, 15 insertions, 61 deletions
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index c72686193d83..ef9554131434 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -288,7 +288,6 @@ struct rxrpc_peer {
struct hlist_node hash_link;
struct rxrpc_local *local;
struct hlist_head error_targets; /* targets for net error distribution */
- struct work_struct error_distributor;
struct rb_root service_conns; /* Service connections */
struct list_head keepalive_link; /* Link in net->peer_keepalive[] */
time64_t last_tx_at; /* Last time packet sent here */
@@ -299,8 +298,6 @@ struct rxrpc_peer {
unsigned int maxdata; /* data size (MTU - hdrsize) */
unsigned short hdrsize; /* header size (IP + UDP + RxRPC) */
int debug_id; /* debug ID for printks */
- int error_report; /* Net (+0) or local (+1000000) to distribute */
-#define RXRPC_LOCAL_ERROR_OFFSET 1000000
struct sockaddr_rxrpc srx; /* remote address */
/* calculated RTT cache */
@@ -1039,7 +1036,6 @@ void rxrpc_send_keepalive(struct rxrpc_peer *);
* peer_event.c
*/
void rxrpc_error_report(struct sock *);
-void rxrpc_peer_error_distributor(struct work_struct *);
void rxrpc_peer_add_rtt(struct rxrpc_call *, enum rxrpc_rtt_rx_trace,
rxrpc_serial_t, rxrpc_serial_t, ktime_t, ktime_t);
void rxrpc_peer_keepalive_worker(struct work_struct *);
@@ -1057,7 +1053,6 @@ void rxrpc_destroy_all_peers(struct rxrpc_net *);
struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *);
struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *);
void rxrpc_put_peer(struct rxrpc_peer *);
-void __rxrpc_queue_peer_error(struct rxrpc_peer *);
/*
* proc.c
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index 9486293fef5c..799f75b6900d 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -400,7 +400,7 @@ void rxrpc_incoming_call(struct rxrpc_sock *rx,
rcu_assign_pointer(conn->channels[chan].call, call);
spin_lock(&conn->params.peer->lock);
- hlist_add_head(&call->error_link, &conn->params.peer->error_targets);
+ hlist_add_head_rcu(&call->error_link, &conn->params.peer->error_targets);
spin_unlock(&conn->params.peer->lock);
_net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id);
diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c
index f8f37188a932..8acf74fe24c0 100644
--- a/net/rxrpc/conn_client.c
+++ b/net/rxrpc/conn_client.c
@@ -710,8 +710,8 @@ int rxrpc_connect_call(struct rxrpc_call *call,
}
spin_lock_bh(&call->conn->params.peer->lock);
- hlist_add_head(&call->error_link,
- &call->conn->params.peer->error_targets);
+ hlist_add_head_rcu(&call->error_link,
+ &call->conn->params.peer->error_targets);
spin_unlock_bh(&call->conn->params.peer->lock);
out:
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index b4438f98dc5c..885dae829f4a 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -216,7 +216,7 @@ void rxrpc_disconnect_call(struct rxrpc_call *call)
call->peer->cong_cwnd = call->cong_cwnd;
spin_lock_bh(&conn->params.peer->lock);
- hlist_del_init(&call->error_link);
+ hlist_del_rcu(&call->error_link);
spin_unlock_bh(&conn->params.peer->lock);
if (rxrpc_is_client_call(call))
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("");
}
/*
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)