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Date: Tue, 23 Aug 2016 16:29:15 +0100
From: David Howells <dhowells@...hat.com>
To: netdev@...r.kernel.org
Cc: dhowells@...hat.com, linux-afs@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: [PATCH net-next 3/3] rxrpc: Perform terminal call ACK/ABORT
retransmission from conn processor
Perform terminal call ACK/ABORT retransmission in the connection processor
rather than in the call processor. With this change, once last_call is
set, no more incoming packets will be routed to the corresponding call or
any earlier calls on that channel (call IDs must only increase on a channel
on a connection).
Further, if a packet's callNumber is before the last_call ID or a packet is
aimed at successfully completed service call then that packet is discarded
and ignored.
Signed-off-by: David Howells <dhowells@...hat.com>
---
net/rxrpc/ar-internal.h | 7 ++-
net/rxrpc/conn_event.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++
net/rxrpc/conn_object.c | 10 ++++
net/rxrpc/input.c | 31 ++++++++++++-
4 files changed, 157 insertions(+), 4 deletions(-)
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index c779b50135f6..7296039c537a 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -295,7 +295,12 @@ struct rxrpc_connection {
u32 call_id; /* ID of current call */
u32 call_counter; /* Call ID counter */
u32 last_call; /* ID of last call */
- u32 last_result; /* Result of last call (0/abort) */
+ u8 last_type; /* Type of last packet */
+ u16 last_service_id;
+ union {
+ u32 last_seq;
+ u32 last_abort;
+ };
} channels[RXRPC_MAXCALLS];
wait_queue_head_t channel_wq; /* queue to wait for channel to become available */
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index c631d926f4db..c1c6b7f305d1 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -25,6 +25,113 @@
#include "ar-internal.h"
/*
+ * Retransmit terminal ACK or ABORT of the previous call.
+ */
+static void rxrpc_conn_retransmit(struct rxrpc_connection *conn,
+ struct sk_buff *skb)
+{
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rxrpc_channel *chan;
+ struct msghdr msg;
+ struct kvec iov;
+ struct {
+ struct rxrpc_wire_header whdr;
+ union {
+ struct {
+ __be32 code;
+ } abort;
+ struct {
+ struct rxrpc_ackpacket ack;
+ struct rxrpc_ackinfo info;
+ };
+ };
+ } __attribute__((packed)) pkt;
+ size_t len;
+ u32 serial, mtu, call_id;
+
+ _enter("%d", conn->debug_id);
+
+ chan = &conn->channels[sp->hdr.cid & RXRPC_CHANNELMASK];
+
+ /* If the last call got moved on whilst we were waiting to run, just
+ * ignore this packet.
+ */
+ call_id = READ_ONCE(chan->last_call);
+ /* Sync with __rxrpc_disconnect_call() */
+ smp_rmb();
+ if (call_id != sp->hdr.callNumber)
+ return;
+
+ msg.msg_name = &conn->params.peer->srx.transport;
+ msg.msg_namelen = conn->params.peer->srx.transport_len;
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_flags = 0;
+
+ pkt.whdr.epoch = htonl(sp->hdr.epoch);
+ pkt.whdr.cid = htonl(sp->hdr.cid);
+ pkt.whdr.callNumber = htonl(sp->hdr.callNumber);
+ pkt.whdr.seq = 0;
+ pkt.whdr.type = chan->last_type;
+ pkt.whdr.flags = conn->out_clientflag;
+ pkt.whdr.userStatus = 0;
+ pkt.whdr.securityIndex = conn->security_ix;
+ pkt.whdr._rsvd = 0;
+ pkt.whdr.serviceId = htons(chan->last_service_id);
+
+ len = sizeof(pkt.whdr);
+ switch (chan->last_type) {
+ case RXRPC_PACKET_TYPE_ABORT:
+ pkt.abort.code = htonl(chan->last_abort);
+ len += sizeof(pkt.abort);
+ break;
+
+ case RXRPC_PACKET_TYPE_ACK:
+ mtu = conn->params.peer->if_mtu;
+ mtu -= conn->params.peer->hdrsize;
+ pkt.ack.bufferSpace = 0;
+ pkt.ack.maxSkew = htons(skb->priority);
+ pkt.ack.firstPacket = htonl(chan->last_seq);
+ pkt.ack.previousPacket = htonl(chan->last_seq - 1);
+ pkt.ack.serial = htonl(sp->hdr.serial);
+ pkt.ack.reason = RXRPC_ACK_DUPLICATE;
+ pkt.ack.nAcks = 0;
+ pkt.info.rxMTU = htonl(rxrpc_rx_mtu);
+ pkt.info.maxMTU = htonl(mtu);
+ pkt.info.rwind = htonl(rxrpc_rx_window_size);
+ pkt.info.jumbo_max = htonl(rxrpc_rx_jumbo_max);
+ len += sizeof(pkt.ack) + sizeof(pkt.info);
+ break;
+ }
+
+ /* Resync with __rxrpc_disconnect_call() and check that the last call
+ * didn't get advanced whilst we were filling out the packets.
+ */
+ smp_rmb();
+ if (READ_ONCE(chan->last_call) != call_id)
+ return;
+
+ iov.iov_base = &pkt;
+ iov.iov_len = len;
+
+ serial = atomic_inc_return(&conn->serial);
+ pkt.whdr.serial = htonl(serial);
+
+ switch (chan->last_type) {
+ case RXRPC_PACKET_TYPE_ABORT:
+ _proto("Tx ABORT %%%u { %d } [re]", serial, conn->local_abort);
+ break;
+ case RXRPC_PACKET_TYPE_ACK:
+ _proto("Tx ACK %%%u [re]", serial);
+ break;
+ }
+
+ kernel_sendmsg(conn->params.local->socket, &msg, &iov, 1, len);
+ _leave("");
+ return;
+}
+
+/*
* pass a connection-level abort onto all calls on that connection
*/
static void rxrpc_abort_calls(struct rxrpc_connection *conn, int state,
@@ -166,6 +273,12 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
_enter("{%d},{%u,%%%u},", conn->debug_id, sp->hdr.type, sp->hdr.serial);
switch (sp->hdr.type) {
+ case RXRPC_PACKET_TYPE_DATA:
+ case RXRPC_PACKET_TYPE_ACK:
+ rxrpc_conn_retransmit(conn, skb);
+ rxrpc_free_skb(skb);
+ return 0;
+
case RXRPC_PACKET_TYPE_ABORT:
if (skb_copy_bits(skb, 0, &wtmp, sizeof(wtmp)) < 0)
return -EPROTO;
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index 743f0bb4aaa8..b4af37ebb112 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -166,7 +166,15 @@ void __rxrpc_disconnect_call(struct rxrpc_call *call)
/* Save the result of the call so that we can repeat it if necessary
* through the channel, whilst disposing of the actual call record.
*/
- chan->last_result = call->local_abort;
+ chan->last_service_id = call->service_id;
+ if (call->local_abort) {
+ chan->last_abort = call->local_abort;
+ chan->last_type = RXRPC_PACKET_TYPE_ABORT;
+ } else {
+ chan->last_seq = call->rx_data_eaten;
+ chan->last_type = RXRPC_PACKET_TYPE_ACK;
+ }
+ /* Sync with rxrpc_conn_retransmit(). */
smp_wmb();
chan->last_call = chan->call_id;
chan->call_id = chan->call_counter;
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 34f7431bf494..66cdeb56f44f 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -566,7 +566,8 @@ done:
/*
* post connection-level events to the connection
- * - this includes challenges, responses and some aborts
+ * - this includes challenges, responses, some aborts and call terminal packet
+ * retransmission.
*/
static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
struct sk_buff *skb)
@@ -716,18 +717,44 @@ void rxrpc_data_ready(struct sock *sk)
/* Connection-level packet */
_debug("CONN %p {%d}", conn, conn->debug_id);
rxrpc_post_packet_to_conn(conn, skb);
+ goto out_unlock;
} else {
/* Call-bound packets are routed by connection channel. */
unsigned int channel = sp->hdr.cid & RXRPC_CHANNELMASK;
struct rxrpc_channel *chan = &conn->channels[channel];
- struct rxrpc_call *call = rcu_dereference(chan->call);
+ struct rxrpc_call *call;
+
+ /* Ignore really old calls */
+ if (sp->hdr.callNumber < chan->last_call)
+ goto discard_unlock;
+
+ if (sp->hdr.callNumber == chan->last_call) {
+ /* For the previous service call, if completed
+ * successfully, we discard all further packets.
+ */
+ if (rxrpc_conn_is_service(call->conn) &&
+ (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
+ sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
+ goto discard_unlock;
+
+ /* But otherwise we need to retransmit the final packet
+ * from data cached in the connection record.
+ */
+ rxrpc_post_packet_to_conn(conn, skb);
+ goto out_unlock;
+ }
+ call = rcu_dereference(chan->call);
if (!call || atomic_read(&call->usage) == 0)
goto cant_route_call;
rxrpc_post_packet_to_call(call, skb);
+ goto out_unlock;
}
+discard_unlock:
+ rxrpc_free_skb(skb);
+out_unlock:
rcu_read_unlock();
out:
return;
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