1 files changed, 186 insertions, 183 deletions

diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c
index 0b54cda3d8e5..7fc50dc7d333 100644
--- a/net/rxrpc/peer_object.c
+++ b/net/rxrpc/peer_object.c
@@ -1,6 +1,6 @@
-/* RxRPC remote transport endpoint management
+/* RxRPC remote transport endpoint record management
  *
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * This program is free software; you can redistribute it and/or
@@ -16,20 +16,132 @@
 #include <linux/skbuff.h>
 #include <linux/udp.h>
 #include <linux/in.h>
-#include <linux/in6.h>
-#include <linux/icmp.h>
 #include <linux/slab.h>
+#include <linux/hashtable.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include <net/ip.h>
 #include <net/route.h>
 #include "ar-internal.h"
 
-static LIST_HEAD(rxrpc_peers);
-static DEFINE_RWLOCK(rxrpc_peer_lock);
-static DECLARE_WAIT_QUEUE_HEAD(rxrpc_peer_wq);
+static DEFINE_HASHTABLE(rxrpc_peer_hash, 10);
+static DEFINE_SPINLOCK(rxrpc_peer_hash_lock);
 
-static void rxrpc_destroy_peer(struct work_struct *work);
+/*
+ * Hash a peer key.
+ */
+static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
+					 const struct sockaddr_rxrpc *srx)
+{
+	const u16 *p;
+	unsigned int i, size;
+	unsigned long hash_key;
+
+	_enter("");
+
+	hash_key = (unsigned long)local / __alignof__(*local);
+	hash_key += srx->transport_type;
+	hash_key += srx->transport_len;
+	hash_key += srx->transport.family;
+
+	switch (srx->transport.family) {
+	case AF_INET:
+		hash_key += (u16 __force)srx->transport.sin.sin_port;
+		size = sizeof(srx->transport.sin.sin_addr);
+		p = (u16 *)&srx->transport.sin.sin_addr;
+		break;
+	}
+
+	/* Step through the peer address in 16-bit portions for speed */
+	for (i = 0; i < size; i += sizeof(*p), p++)
+		hash_key += *p;
+
+	_leave(" 0x%lx", hash_key);
+	return hash_key;
+}
+
+/*
+ * Compare a peer to a key.  Return -ve, 0 or +ve to indicate less than, same
+ * or greater than.
+ *
+ * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
+ * buckets and mid-bucket insertion, so we don't make full use of this
+ * information at this point.
+ */
+static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
+			       struct rxrpc_local *local,
+			       const struct sockaddr_rxrpc *srx,
+			       unsigned long hash_key)
+{
+	long diff;
+
+	diff = ((peer->hash_key - hash_key) ?:
+		((unsigned long)peer->local - (unsigned long)local) ?:
+		(peer->srx.transport_type - srx->transport_type) ?:
+		(peer->srx.transport_len - srx->transport_len) ?:
+		(peer->srx.transport.family - srx->transport.family));
+	if (diff != 0)
+		return diff;
+
+	switch (srx->transport.family) {
+	case AF_INET:
+		return ((u16 __force)peer->srx.transport.sin.sin_port -
+			(u16 __force)srx->transport.sin.sin_port) ?:
+			memcmp(&peer->srx.transport.sin.sin_addr,
+			       &srx->transport.sin.sin_addr,
+			       sizeof(struct in_addr));
+	default:
+		BUG();
+	}
+}
+
+/*
+ * Look up a remote transport endpoint for the specified address using RCU.
+ */
+static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
+	struct rxrpc_local *local,
+	const struct sockaddr_rxrpc *srx,
+	unsigned long hash_key)
+{
+	struct rxrpc_peer *peer;
+
+	hash_for_each_possible_rcu(rxrpc_peer_hash, peer, hash_link, hash_key) {
+		if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0) {
+			if (atomic_read(&peer->usage) == 0)
+				return NULL;
+			return peer;
+		}
+	}
+
+	return NULL;
+}
+
+/*
+ * Look up a remote transport endpoint for the specified address using RCU.
+ */
+struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
+					 const struct sockaddr_rxrpc *srx)
+{
+	struct rxrpc_peer *peer;
+	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
+
+	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
+	if (peer) {
+		switch (srx->transport.family) {
+		case AF_INET:
+			_net("PEER %d {%d,%u,%pI4+%hu}",
+			     peer->debug_id,
+			     peer->srx.transport_type,
+			     peer->srx.transport.family,
+			     &peer->srx.transport.sin.sin_addr,
+			     ntohs(peer->srx.transport.sin.sin_port));
+			break;
+		}
+
+		_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
+	}
+	return peer;
+}
 
 /*
  * assess the MTU size for the network interface through which this peer is
@@ -58,10 +170,9 @@ static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
 }
 
 /*
- * allocate a new peer
+ * Allocate a peer.
  */
-static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx,
-					   gfp_t gfp)
+struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
 {
 	struct rxrpc_peer *peer;
 
@@ -69,12 +180,32 @@ static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx,
 
 	peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
 	if (peer) {
-		INIT_WORK(&peer->destroyer, &rxrpc_destroy_peer);
-		INIT_LIST_HEAD(&peer->link);
+		atomic_set(&peer->usage, 1);
+		peer->local = local;
 		INIT_LIST_HEAD(&peer->error_targets);
 		spin_lock_init(&peer->lock);
-		atomic_set(&peer->usage, 1);
 		peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
+	}
+
+	_leave(" = %p", peer);
+	return peer;
+}
+
+/*
+ * Set up a new peer.
+ */
+static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
+					    struct sockaddr_rxrpc *srx,
+					    unsigned long hash_key,
+					    gfp_t gfp)
+{
+	struct rxrpc_peer *peer;
+
+	_enter("");
+
+	peer = rxrpc_alloc_peer(local, gfp);
+	if (peer) {
+		peer->hash_key = hash_key;
 		memcpy(&peer->srx, srx, sizeof(*srx));
 
 		rxrpc_assess_MTU_size(peer);
@@ -105,11 +236,11 @@ static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx,
 /*
  * obtain a remote transport endpoint for the specified address
  */
-struct rxrpc_peer *rxrpc_get_peer(struct sockaddr_rxrpc *srx, gfp_t gfp)
+struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
+				     struct sockaddr_rxrpc *srx, gfp_t gfp)
 {
 	struct rxrpc_peer *peer, *candidate;
-	const char *new = "old";
-	int usage;
+	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 
 	_enter("{%d,%d,%pI4+%hu}",
 	       srx->transport_type,
@@ -118,188 +249,60 @@ struct rxrpc_peer *rxrpc_get_peer(struct sockaddr_rxrpc *srx, gfp_t gfp)
 	       ntohs(srx->transport.sin.sin_port));
 
 	/* search the peer list first */
-	read_lock_bh(&rxrpc_peer_lock);
-	list_for_each_entry(peer, &rxrpc_peers, link) {
-		_debug("check PEER %d { u=%d t=%d l=%d }",
-		       peer->debug_id,
-		       atomic_read(&peer->usage),
-		       peer->srx.transport_type,
-		       peer->srx.transport_len);
-
-		if (atomic_read(&peer->usage) > 0 &&
-		    peer->srx.transport_type == srx->transport_type &&
-		    peer->srx.transport_len == srx->transport_len &&
-		    memcmp(&peer->srx.transport,
-			   &srx->transport,
-			   srx->transport_len) == 0)
-			goto found_extant_peer;
-	}
-	read_unlock_bh(&rxrpc_peer_lock);
-
-	/* not yet present - create a candidate for a new record and then
-	 * redo the search */
-	candidate = rxrpc_alloc_peer(srx, gfp);
-	if (!candidate) {
-		_leave(" = -ENOMEM");
-		return ERR_PTR(-ENOMEM);
-	}
+	rcu_read_lock();
+	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
+	if (peer && !rxrpc_get_peer_maybe(peer))
+		peer = NULL;
+	rcu_read_unlock();
+
+	if (!peer) {
+		/* The peer is not yet present in hash - create a candidate
+		 * for a new record and then redo the search.
+		 */
+		candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
+		if (!candidate) {
+			_leave(" = NULL [nomem]");
+			return NULL;
+		}
 
-	write_lock_bh(&rxrpc_peer_lock);
+		spin_lock(&rxrpc_peer_hash_lock);
 
-	list_for_each_entry(peer, &rxrpc_peers, link) {
-		if (atomic_read(&peer->usage) > 0 &&
-		    peer->srx.transport_type == srx->transport_type &&
-		    peer->srx.transport_len == srx->transport_len &&
-		    memcmp(&peer->srx.transport,
-			   &srx->transport,
-			   srx->transport_len) == 0)
-			goto found_extant_second;
-	}
+		/* Need to check that we aren't racing with someone else */
+		peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
+		if (peer && !rxrpc_get_peer_maybe(peer))
+			peer = NULL;
+		if (!peer)
+			hash_add_rcu(rxrpc_peer_hash,
+				     &candidate->hash_link, hash_key);
 
-	/* we can now add the new candidate to the list */
-	peer = candidate;
-	candidate = NULL;
-	usage = atomic_read(&peer->usage);
+		spin_unlock(&rxrpc_peer_hash_lock);
 
-	list_add_tail(&peer->link, &rxrpc_peers);
-	write_unlock_bh(&rxrpc_peer_lock);
-	new = "new";
+		if (peer)
+			kfree(candidate);
+		else
+			peer = candidate;
+	}
 
-success:
-	_net("PEER %s %d {%d,%u,%pI4+%hu}",
-	     new,
+	_net("PEER %d {%d,%pI4+%hu}",
 	     peer->debug_id,
 	     peer->srx.transport_type,
-	     peer->srx.transport.family,
 	     &peer->srx.transport.sin.sin_addr,
 	     ntohs(peer->srx.transport.sin.sin_port));
 
-	_leave(" = %p {u=%d}", peer, usage);
-	return peer;
-
-	/* we found the peer in the list immediately */
-found_extant_peer:
-	usage = atomic_inc_return(&peer->usage);
-	read_unlock_bh(&rxrpc_peer_lock);
-	goto success;
-
-	/* we found the peer on the second time through the list */
-found_extant_second:
-	usage = atomic_inc_return(&peer->usage);
-	write_unlock_bh(&rxrpc_peer_lock);
-	kfree(candidate);
-	goto success;
-}
-
-/*
- * find the peer associated with a packet
- */
-struct rxrpc_peer *rxrpc_find_peer(struct rxrpc_local *local,
-				   __be32 addr, __be16 port)
-{
-	struct rxrpc_peer *peer;
-
-	_enter("");
-
-	/* search the peer list */
-	read_lock_bh(&rxrpc_peer_lock);
-
-	if (local->srx.transport.family == AF_INET &&
-	    local->srx.transport_type == SOCK_DGRAM
-	    ) {
-		list_for_each_entry(peer, &rxrpc_peers, link) {
-			if (atomic_read(&peer->usage) > 0 &&
-			    peer->srx.transport_type == SOCK_DGRAM &&
-			    peer->srx.transport.family == AF_INET &&
-			    peer->srx.transport.sin.sin_port == port &&
-			    peer->srx.transport.sin.sin_addr.s_addr == addr)
-				goto found_UDP_peer;
-		}
-
-		goto new_UDP_peer;
-	}
-
-	read_unlock_bh(&rxrpc_peer_lock);
-	_leave(" = -EAFNOSUPPORT");
-	return ERR_PTR(-EAFNOSUPPORT);
-
-found_UDP_peer:
-	_net("Rx UDP DGRAM from peer %d", peer->debug_id);
-	atomic_inc(&peer->usage);
-	read_unlock_bh(&rxrpc_peer_lock);
-	_leave(" = %p", peer);
+	_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
 	return peer;
-
-new_UDP_peer:
-	_net("Rx UDP DGRAM from NEW peer");
-	read_unlock_bh(&rxrpc_peer_lock);
-	_leave(" = -EBUSY [new]");
-	return ERR_PTR(-EBUSY);
 }
 
 /*
- * release a remote transport endpoint
+ * Discard a ref on a remote peer record.
  */
-void rxrpc_put_peer(struct rxrpc_peer *peer)
+void __rxrpc_put_peer(struct rxrpc_peer *peer)
 {
-	_enter("%p{u=%d}", peer, atomic_read(&peer->usage));
+	ASSERT(list_empty(&peer->error_targets));
 
-	ASSERTCMP(atomic_read(&peer->usage), >, 0);
-
-	if (likely(!atomic_dec_and_test(&peer->usage))) {
-		_leave(" [in use]");
-		return;
-	}
-
-	rxrpc_queue_work(&peer->destroyer);
-	_leave("");
-}
-
-/*
- * destroy a remote transport endpoint
- */
-static void rxrpc_destroy_peer(struct work_struct *work)
-{
-	struct rxrpc_peer *peer =
-		container_of(work, struct rxrpc_peer, destroyer);
-
-	_enter("%p{%d}", peer, atomic_read(&peer->usage));
-
-	write_lock_bh(&rxrpc_peer_lock);
-	list_del(&peer->link);
-	write_unlock_bh(&rxrpc_peer_lock);
-
-	_net("DESTROY PEER %d", peer->debug_id);
-	kfree(peer);
-
-	if (list_empty(&rxrpc_peers))
-		wake_up_all(&rxrpc_peer_wq);
-	_leave("");
-}
-
-/*
- * preemptively destroy all the peer records from a transport endpoint rather
- * than waiting for them to time out
- */
-void __exit rxrpc_destroy_all_peers(void)
-{
-	DECLARE_WAITQUEUE(myself,current);
-
-	_enter("");
-
-	/* we simply have to wait for them to go away */
-	if (!list_empty(&rxrpc_peers)) {
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		add_wait_queue(&rxrpc_peer_wq, &myself);
-
-		while (!list_empty(&rxrpc_peers)) {
-			schedule();
-			set_current_state(TASK_UNINTERRUPTIBLE);
-		}
-
-		remove_wait_queue(&rxrpc_peer_wq, &myself);
-		set_current_state(TASK_RUNNING);
-	}
+	spin_lock(&rxrpc_peer_hash_lock);
+	hash_del_rcu(&peer->hash_link);
+	spin_unlock(&rxrpc_peer_hash_lock);
 
-	_leave("");
+	kfree_rcu(peer, rcu);
 }