Subject: [RFC 1/4] net: pppoe - code cleanup and helpers

From: Cyrill Gorcunov <[email-masked]>
Date: Fri, 09 Jan 2009 22:51:55 +0300

- Introduce PPPOE_HASH_MASK.
- Remove redundant declaration of pppoe_chan_ops.
- Introduce stage_session helper.
- Tabs, space, long-line-split cleanup.

CC: Michal Ostrowski <[email-masked]>
Signed-off-by: Cyrill Gorcunov <[email-masked]>
---
 drivers/net/pppoe.c |  167 ++++++++++++++++++++++++++--------------------------
 1 file changed, 86 insertions(+), 81 deletions(-)

Index: linux-2.6.git/drivers/net/pppoe.c
===================================================================
--- linux-2.6.git.orig/drivers/net/pppoe.c
+++ linux-2.6.git/drivers/net/pppoe.c
@@ -84,32 +84,43 @@
 #include <asm/uaccess.h>
 
 #define PPPOE_HASH_BITS 4
-#define PPPOE_HASH_SIZE (1<<PPPOE_HASH_BITS)
-
-static struct ppp_channel_ops pppoe_chan_ops;
+#define PPPOE_HASH_SIZE (1 << PPPOE_HASH_BITS)
+#define PPPOE_HASH_MASK	(PPPOE_HASH_SIZE - 1)
 
 static int pppoe_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
 static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb);
 static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb);
 
 static const struct proto_ops pppoe_ops;
+static struct ppp_channel_ops pppoe_chan_ops;
 static DEFINE_RWLOCK(pppoe_hash_lock);
 
-static struct ppp_channel_ops pppoe_chan_ops;
+/*
+ * PPPoE could be in the following stages:
+ * 1) Discovery stage (to obtain remote MAC and Session ID)
+ * 2) Session stage (MAC and SID are known)
+ *
+ * Ethernet frames have a special tag for this but
+ * we use simplier approach based on session id
+ */
+static inline bool stage_session(__be16 sid)
+{
+	return sid != 0;
+}
 
 static inline int cmp_2_addr(struct pppoe_addr *a, struct pppoe_addr *b)
 {
-	return (a->sid == b->sid &&
-		(memcmp(a->remote, b->remote, ETH_ALEN) == 0));
+	return a->sid == b->sid &&
+		(memcmp(a->remote, b->remote, ETH_ALEN) == 0);
 }
 
 static inline int cmp_addr(struct pppoe_addr *a, __be16 sid, char *addr)
 {
-	return (a->sid == sid &&
-		(memcmp(a->remote,addr,ETH_ALEN) == 0));
+	return a->sid == sid &&
+		(memcmp(a->remote, addr, ETH_ALEN) == 0);
 }
 
-#if 8%PPPOE_HASH_BITS
+#if 8 % PPPOE_HASH_BITS
 #error 8 must be a multiple of PPPOE_HASH_BITS
 #endif
 
@@ -118,17 +129,14 @@ static int hash_item(__be16 sid, unsigne
 	unsigned char hash = 0;
 	unsigned int i;
 
-	for (i = 0 ; i < ETH_ALEN ; i++) {
+	for (i = 0; i < ETH_ALEN; i++)
 		hash ^= addr[i];
-	}
-	for (i = 0 ; i < sizeof(sid_t)*8 ; i += 8 ){
-		hash ^= (__force __u32)sid>>i;
-	}
-	for (i = 8 ; (i>>=1) >= PPPOE_HASH_BITS ; ) {
-		hash ^= hash>>i;
-	}
+	for (i = 0; i < sizeof(sid_t) * 8; i += 8)
+		hash ^= (__force __u32)sid >> i;
+	for (i = 8; (i >>= 1) >= PPPOE_HASH_BITS;)
+		hash ^= hash >> i;
 
-	return hash & ( PPPOE_HASH_SIZE - 1 );
+	return hash & PPPOE_HASH_MASK;
 }
 
 /* zeroed because its in .bss */
@@ -146,10 +154,15 @@ static struct pppox_sock *__get_item(__b
 
 	ret = item_hash_table[hash];
 
-	while (ret && !(cmp_addr(&ret->pppoe_pa, sid, addr) && ret->pppoe_ifindex == ifindex))
+	while (ret) {
+		if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
+		    ret->pppoe_ifindex == ifindex)
+			return ret;
+
 		ret = ret->next;
+	}
 
-	return ret;
+	return NULL;
 }
 
 static int __set_item(struct pppox_sock *po)
@@ -159,7 +172,8 @@ static int __set_item(struct pppox_sock 
 
 	ret = item_hash_table[hash];
 	while (ret) {
-		if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) && ret->pppoe_ifindex == po->pppoe_ifindex)
+		if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) &&
+		    ret->pppoe_ifindex == po->pppoe_ifindex)
 			return -EALREADY;
 
 		ret = ret->next;
@@ -180,7 +194,8 @@ static struct pppox_sock *__delete_item(
 	src = &item_hash_table[hash];
 
 	while (ret) {
-		if (cmp_addr(&ret->pppoe_pa, sid, addr) && ret->pppoe_ifindex == ifindex) {
+		if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
+		    ret->pppoe_ifindex == ifindex) {
 			*src = ret->next;
 			break;
 		}
@@ -217,7 +232,7 @@ static inline struct pppox_sock *get_ite
 	int ifindex;
 
 	dev = dev_get_by_name(&init_net, sp->sa_addr.pppoe.dev);
-	if(!dev)
+	if (!dev)
 		return NULL;
 	ifindex = dev->ifindex;
 	dev_put(dev);
@@ -329,7 +344,6 @@ static struct notifier_block pppoe_notif
 	.notifier_call = pppoe_device_event,
 };
 
-
 /************************************************************************
  *
  * Do the real work of receiving a PPPoE Session frame.
@@ -383,7 +397,8 @@ static int pppoe_rcv(struct sk_buff *skb
 	struct pppox_sock *po;
 	int len;
 
-	if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
 		goto out;
 
 	if (dev_net(dev) != &init_net)
@@ -432,7 +447,8 @@ static int pppoe_disc_rcv(struct sk_buff
 	if (dev_net(dev) != &init_net)
 		goto abort;
 
-	if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
 		goto out;
 
 	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
@@ -493,12 +509,11 @@ static struct proto pppoe_sk_proto = {
  **********************************************************************/
 static int pppoe_create(struct net *net, struct socket *sock)
 {
-	int error = -ENOMEM;
 	struct sock *sk;
 
 	sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppoe_sk_proto);
 	if (!sk)
-		goto out;
+		return -ENOMEM;
 
 	sock_init_data(sock, sk);
 
@@ -511,8 +526,7 @@ static int pppoe_create(struct net *net,
 	sk->sk_family	   = PF_PPPOX;
 	sk->sk_protocol	   = PX_PROTO_OE;
 
-	error = 0;
-out:	return error;
+	return 0;
 }
 
 static int pppoe_release(struct socket *sock)
@@ -524,7 +538,7 @@ static int pppoe_release(struct socket *
 		return 0;
 
 	lock_sock(sk);
-	if (sock_flag(sk, SOCK_DEAD)){
+	if (sock_flag(sk, SOCK_DEAD)) {
 		release_sock(sk);
 		return -EBADF;
 	}
@@ -542,7 +556,7 @@ static int pppoe_release(struct socket *
 	write_lock_bh(&pppoe_hash_lock);
 
 	po = pppox_sk(sk);
-	if (po->pppoe_pa.sid) {
+	if (stage_session(po->pppoe_pa.sid)) {
 		__delete_item(po->pppoe_pa.sid,
 			      po->pppoe_pa.remote, po->pppoe_ifindex);
 	}
@@ -564,7 +578,6 @@ static int pppoe_release(struct socket *
 	return 0;
 }
 
-
 static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
 		  int sockaddr_len, int flags)
 {
@@ -582,32 +595,31 @@ static int pppoe_connect(struct socket *
 
 	/* Check for already bound sockets */
 	error = -EBUSY;
-	if ((sk->sk_state & PPPOX_CONNECTED) && sp->sa_addr.pppoe.sid)
+	if ((sk->sk_state & PPPOX_CONNECTED) &&
+	     stage_session(sp->sa_addr.pppoe.sid))
 		goto end;
 
 	/* Check for already disconnected sockets, on attempts to disconnect */
 	error = -EALREADY;
-	if ((sk->sk_state & PPPOX_DEAD) && !sp->sa_addr.pppoe.sid )
+	if ((sk->sk_state & PPPOX_DEAD) &&
+	     !stage_session(sp->sa_addr.pppoe.sid))
 		goto end;
 
 	error = 0;
-	if (po->pppoe_pa.sid) {
-		pppox_unbind_sock(sk);
-
-		/* Delete the old binding */
-		delete_item(po->pppoe_pa.sid,po->pppoe_pa.remote,po->pppoe_ifindex);
 
-		if(po->pppoe_dev)
+	/* Delete the old binding */
+	if (stage_session(po->pppoe_pa.sid)) {
+		pppox_unbind_sock(sk);
+		delete_item(po->pppoe_pa.sid, po->pppoe_pa.remote, po->pppoe_ifindex);
+		if (po->pppoe_dev)
 			dev_put(po->pppoe_dev);
-
 		memset(sk_pppox(po) + 1, 0,
 		       sizeof(struct pppox_sock) - sizeof(struct sock));
-
 		sk->sk_state = PPPOX_NONE;
 	}
 
-	/* Don't re-bind if sid==0 */
-	if (sp->sa_addr.pppoe.sid != 0) {
+	/* Re-bind in session stage only */
+	if (stage_session(sp->sa_addr.pppoe.sid)) {
 		dev = dev_get_by_name(&init_net, sp->sa_addr.pppoe.dev);
 
 		error = -ENODEV;
@@ -618,7 +630,7 @@ static int pppoe_connect(struct socket *
 		po->pppoe_ifindex = dev->ifindex;
 
 		write_lock_bh(&pppoe_hash_lock);
-		if (!(dev->flags & IFF_UP)){
+		if (!(dev->flags & IFF_UP)) {
 			write_unlock_bh(&pppoe_hash_lock);
 			goto err_put;
 		}
@@ -648,7 +660,7 @@ static int pppoe_connect(struct socket *
 
 	po->num = sp->sa_addr.pppoe.sid;
 
- end:
+end:
 	release_sock(sk);
 	return error;
 err_put:
@@ -659,7 +671,6 @@ err_put:
 	goto end;
 }
 
-
 static int pppoe_getname(struct socket *sock, struct sockaddr *uaddr,
 		  int *usockaddr_len, int peer)
 {
@@ -678,7 +689,6 @@ static int pppoe_getname(struct socket *
 	return 0;
 }
 
-
 static int pppoe_ioctl(struct socket *sock, unsigned int cmd,
 		unsigned long arg)
 {
@@ -709,7 +719,7 @@ static int pppoe_ioctl(struct socket *so
 			break;
 
 		err = -EFAULT;
-		if (get_user(val,(int __user *) arg))
+		if (get_user(val, (int __user *)arg))
 			break;
 
 		if (val < (po->pppoe_dev->mtu
@@ -722,7 +732,7 @@ static int pppoe_ioctl(struct socket *so
 
 	case PPPIOCSFLAGS:
 		err = -EFAULT;
-		if (get_user(val, (int __user *) arg))
+		if (get_user(val, (int __user *)arg))
 			break;
 		err = 0;
 		break;
@@ -749,7 +759,7 @@ static int pppoe_ioctl(struct socket *so
 
 		err = -EINVAL;
 		if (po->pppoe_relay.sa_family != AF_PPPOX ||
-		    po->pppoe_relay.sa_protocol!= PX_PROTO_OE)
+		    po->pppoe_relay.sa_protocol != PX_PROTO_OE)
 			break;
 
 		/* Check that the socket referenced by the address
@@ -781,7 +791,6 @@ static int pppoe_ioctl(struct socket *so
 	return err;
 }
 
-
 static int pppoe_sendmsg(struct kiocb *iocb, struct socket *sock,
 		  struct msghdr *m, size_t total_len)
 {
@@ -808,7 +817,7 @@ static int pppoe_sendmsg(struct kiocb *i
 	dev = po->pppoe_dev;
 
 	error = -EMSGSIZE;
- 	if (total_len > (dev->mtu + dev->hard_header_len))
+	if (total_len > (dev->mtu + dev->hard_header_len))
 		goto end;

@@ -853,7 +862,6 @@ end:
 	return error;
 }
 
-
 /************************************************************************
  *
  * xmit function for internal use.
@@ -903,7 +911,6 @@ abort:
 	return 1;
 }
 
-
 /************************************************************************
  *
  * xmit function called by generic PPP driver
@@ -916,7 +923,6 @@ static int pppoe_xmit(struct ppp_channel
 	return __pppoe_xmit(sk, skb);
 }
 
-
 static struct ppp_channel_ops pppoe_chan_ops = {
 	.start_xmit = pppoe_xmit,
 };
@@ -976,9 +982,9 @@ out:
 static __inline__ struct pppox_sock *pppoe_get_idx(loff_t pos)
 {
 	struct pppox_sock *po;
-	int i = 0;
+	int i;
 
-	for (; i < PPPOE_HASH_SIZE; i++) {
+	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
 		po = item_hash_table[i];
 		while (po) {
 			if (!pos--)
@@ -1064,32 +1070,31 @@ static inline int pppoe_proc_init(void) 
 #endif /* CONFIG_PROC_FS */
 
 static const struct proto_ops pppoe_ops = {
-    .family		= AF_PPPOX,
-    .owner		= THIS_MODULE,
-    .release		= pppoe_release,
-    .bind		= sock_no_bind,
-    .connect		= pppoe_connect,
-    .socketpair		= sock_no_socketpair,
-    .accept		= sock_no_accept,
-    .getname		= pppoe_getname,
-    .poll		= datagram_poll,
-    .listen		= sock_no_listen,
-    .shutdown		= sock_no_shutdown,
-    .setsockopt		= sock_no_setsockopt,
-    .getsockopt		= sock_no_getsockopt,
-    .sendmsg		= pppoe_sendmsg,
-    .recvmsg		= pppoe_recvmsg,
-    .mmap		= sock_no_mmap,
-    .ioctl		= pppox_ioctl,
+	.family		= AF_PPPOX,
+	.owner		= THIS_MODULE,
+	.release	= pppoe_release,
+	.bind		= sock_no_bind,
+	.connect	= pppoe_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= sock_no_accept,
+	.getname	= pppoe_getname,
+	.poll		= datagram_poll,
+	.listen		= sock_no_listen,
+	.shutdown	= sock_no_shutdown,
+	.setsockopt	= sock_no_setsockopt,
+	.getsockopt	= sock_no_getsockopt,
+	.sendmsg	= pppoe_sendmsg,
+	.recvmsg	= pppoe_recvmsg,
+	.mmap		= sock_no_mmap,
+	.ioctl		= pppox_ioctl,
 };
 
 static struct pppox_proto pppoe_proto = {
-    .create	= pppoe_create,
-    .ioctl	= pppoe_ioctl,
-    .owner	= THIS_MODULE,
+	.create	= pppoe_create,
+	.ioctl	= pppoe_ioctl,
+	.owner	= THIS_MODULE,
 };
 
-
 static int __init pppoe_init(void)
 {
 	int err = proto_register(&pppoe_sk_proto, 0);
@@ -1097,7 +1102,7 @@ static int __init pppoe_init(void)
 	if (err)
 		goto out;
 
- 	err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
+	err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
 	if (err)
 		goto out_unregister_pppoe_proto;

--