af_rxrpc: Keep rxrpc_call pointers in a hashtable

Keep track of rxrpc_call structures in a hashtable so they can be
found directly from the network parameters which define the call.

This allows incoming packets to be routed directly to a call without walking
through hierarchy of peer -> transport -> connection -> call and all the
spinlocks that that entailed.

Signed-off-by: Tim Smith <tim@electronghost.co.uk>
Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 73 insertions, 104 deletions

diff --git a/net/rxrpc/ar-input.c b/net/rxrpc/ar-input.c
index e449c675c36a..73742647c135 100644
--- a/net/rxrpc/ar-input.c
+++ b/net/rxrpc/ar-input.c
@@ -523,36 +523,38 @@ protocol_error:
  * post an incoming packet to the appropriate call/socket to deal with
  * - must get rid of the sk_buff, either by freeing it or by queuing it
  */
-static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
+static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
 				      struct sk_buff *skb)
 {
 	struct rxrpc_skb_priv *sp;
-	struct rxrpc_call *call;
-	struct rb_node *p;
-	__be32 call_id;
 
-	_enter("%p,%p", conn, skb);
-
-	read_lock_bh(&conn->lock);
+	_enter("%p,%p", call, skb);
 
 	sp = rxrpc_skb(skb);
 
-	/* look at extant calls by channel number first */
-	call = conn->channels[ntohl(sp->hdr.cid) & RXRPC_CHANNELMASK];
-	if (!call || call->call_id != sp->hdr.callNumber)
-		goto call_not_extant;
-
 	_debug("extant call [%d]", call->state);
-	ASSERTCMP(call->conn, ==, conn);
 
 	read_lock(&call->state_lock);
 	switch (call->state) {
 	case RXRPC_CALL_LOCALLY_ABORTED:
-		if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
+		if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events)) {
 			rxrpc_queue_call(call);
+			goto free_unlock;
+		}
 	case RXRPC_CALL_REMOTELY_ABORTED:
 	case RXRPC_CALL_NETWORK_ERROR:
 	case RXRPC_CALL_DEAD:
+		goto dead_call;
+	case RXRPC_CALL_COMPLETE:
+	case RXRPC_CALL_CLIENT_FINAL_ACK:
+		/* complete server call */
+		if (call->conn->in_clientflag)
+			goto dead_call;
+		/* resend last packet of a completed call */
+		_debug("final ack again");
+		rxrpc_get_call(call);
+		set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
+		rxrpc_queue_call(call);
 		goto free_unlock;
 	default:
 		break;
@@ -560,7 +562,6 @@ static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
 
 	read_unlock(&call->state_lock);
 	rxrpc_get_call(call);
-	read_unlock_bh(&conn->lock);
 
 	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 	    sp->hdr.flags & RXRPC_JUMBO_PACKET)
@@ -571,80 +572,16 @@ static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
 	rxrpc_put_call(call);
 	goto done;
 
-call_not_extant:
-	/* search the completed calls in case what we're dealing with is
-	 * there */
-	_debug("call not extant");
-
-	call_id = sp->hdr.callNumber;
-	p = conn->calls.rb_node;
-	while (p) {
-		call = rb_entry(p, struct rxrpc_call, conn_node);
-
-		if (call_id < call->call_id)
-			p = p->rb_left;
-		else if (call_id > call->call_id)
-			p = p->rb_right;
-		else
-			goto found_completed_call;
-	}
-
 dead_call:
-	/* it's a either a really old call that we no longer remember or its a
-	 * new incoming call */
-	read_unlock_bh(&conn->lock);
-
-	if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
-	    sp->hdr.seq == cpu_to_be32(1)) {
-		_debug("incoming call");
-		skb_queue_tail(&conn->trans->local->accept_queue, skb);
-		rxrpc_queue_work(&conn->trans->local->acceptor);
-		goto done;
-	}
-
-	_debug("dead call");
 	if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 		skb->priority = RX_CALL_DEAD;
-		rxrpc_reject_packet(conn->trans->local, skb);
-	}
-	goto done;
-
-	/* resend last packet of a completed call
-	 * - client calls may have been aborted or ACK'd
-	 * - server calls may have been aborted
-	 */
-found_completed_call:
-	_debug("completed call");
-
-	if (atomic_read(&call->usage) == 0)
-		goto dead_call;
-
-	/* synchronise any state changes */
-	read_lock(&call->state_lock);
-	ASSERTIFCMP(call->state != RXRPC_CALL_CLIENT_FINAL_ACK,
-		    call->state, >=, RXRPC_CALL_COMPLETE);
-
-	if (call->state == RXRPC_CALL_LOCALLY_ABORTED ||
-	    call->state == RXRPC_CALL_REMOTELY_ABORTED ||
-	    call->state == RXRPC_CALL_DEAD) {
-		read_unlock(&call->state_lock);
-		goto dead_call;
+		rxrpc_reject_packet(call->conn->trans->local, skb);
+		goto unlock;
 	}
-
-	if (call->conn->in_clientflag) {
-		read_unlock(&call->state_lock);
-		goto dead_call; /* complete server call */
-	}
-
-	_debug("final ack again");
-	rxrpc_get_call(call);
-	set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
-	rxrpc_queue_call(call);
-
 free_unlock:
-	read_unlock(&call->state_lock);
-	read_unlock_bh(&conn->lock);
 	rxrpc_free_skb(skb);
+unlock:
+	read_unlock(&call->state_lock);
 done:
 	_leave("");
 }
@@ -663,17 +600,42 @@ static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 	rxrpc_queue_conn(conn);
 }
 
+static struct rxrpc_connection *rxrpc_conn_from_local(struct rxrpc_local *local,
+					       struct sk_buff *skb,
+					       struct rxrpc_skb_priv *sp)
+{
+	struct rxrpc_peer *peer;
+	struct rxrpc_transport *trans;
+	struct rxrpc_connection *conn;
+
+	peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr,
+				udp_hdr(skb)->source);
+	if (IS_ERR(peer))
+		goto cant_find_conn;
+
+	trans = rxrpc_find_transport(local, peer);
+	rxrpc_put_peer(peer);
+	if (!trans)
+		goto cant_find_conn;
+
+	conn = rxrpc_find_connection(trans, &sp->hdr);
+	rxrpc_put_transport(trans);
+	if (!conn)
+		goto cant_find_conn;
+
+	return conn;
+cant_find_conn:
+	return NULL;
+}
+
 /*
  * handle data received on the local endpoint
  * - may be called in interrupt context
  */
 void rxrpc_data_ready(struct sock *sk, int count)
 {
-	struct rxrpc_connection *conn;
-	struct rxrpc_transport *trans;
 	struct rxrpc_skb_priv *sp;
 	struct rxrpc_local *local;
-	struct rxrpc_peer *peer;
 	struct sk_buff *skb;
 	int ret;
 
@@ -748,27 +710,34 @@ void rxrpc_data_ready(struct sock *sk, int count)
 	    (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
 		goto bad_message;
 
-	peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr, udp_hdr(skb)->source);
-	if (IS_ERR(peer))
-		goto cant_route_call;
-
-	trans = rxrpc_find_transport(local, peer);
-	rxrpc_put_peer(peer);
-	if (!trans)
-		goto cant_route_call;
-
-	conn = rxrpc_find_connection(trans, &sp->hdr);
-	rxrpc_put_transport(trans);
-	if (!conn)
-		goto cant_route_call;
+	if (sp->hdr.callNumber == 0) {
+		/* This is a connection-level packet. These should be
+		 * fairly rare, so the extra overhead of looking them up the
+		 * old-fashioned way doesn't really hurt */
+		struct rxrpc_connection *conn;
 
-	_debug("CONN %p {%d}", conn, conn->debug_id);
+		conn = rxrpc_conn_from_local(local, skb, sp);
+		if (!conn)
+			goto cant_route_call;
 
-	if (sp->hdr.callNumber == 0)
+		_debug("CONN %p {%d}", conn, conn->debug_id);
 		rxrpc_post_packet_to_conn(conn, skb);
-	else
-		rxrpc_post_packet_to_call(conn, skb);
-	rxrpc_put_connection(conn);
+		rxrpc_put_connection(conn);
+	} else {
+		struct rxrpc_call *call;
+		u8 in_clientflag = 0;
+
+		if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
+			in_clientflag = RXRPC_CLIENT_INITIATED;
+		call = rxrpc_find_call_hash(in_clientflag, sp->hdr.cid,
+					    sp->hdr.callNumber, sp->hdr.epoch,
+					    sp->hdr.serviceId, local, AF_INET,
+					    (u8 *)&ip_hdr(skb)->saddr);
+		if (call)
+			rxrpc_post_packet_to_call(call, skb);
+		else
+			goto cant_route_call;
+	}
 	rxrpc_put_local(local);
 	return;