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authorDavid S. Miller <davem@davemloft.net>2009-10-27 01:03:26 -0700
committerDavid S. Miller <davem@davemloft.net>2009-10-27 01:03:26 -0700
commitcfadf853f6cd9689f79a63ca960c6f9d6665314f (patch)
tree35418e342d9783f0974ea33ef03875aa21d2362a /drivers/net/pppoe.c
parentvlan: allow null VLAN ID to be used (diff)
parentsh_eth: Add asm/cacheflush.h (diff)
downloadlinux-dev-cfadf853f6cd9689f79a63ca960c6f9d6665314f.tar.xz
linux-dev-cfadf853f6cd9689f79a63ca960c6f9d6665314f.zip
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts: drivers/net/sh_eth.c
Diffstat (limited to 'drivers/net/pppoe.c')
-rw-r--r--drivers/net/pppoe.c129
1 files changed, 68 insertions, 61 deletions
diff --git a/drivers/net/pppoe.c b/drivers/net/pppoe.c
index 7cbf6f9b51de..2559991eea6a 100644
--- a/drivers/net/pppoe.c
+++ b/drivers/net/pppoe.c
@@ -111,9 +111,6 @@ struct pppoe_net {
rwlock_t hash_lock;
};
-/* to eliminate a race btw pppoe_flush_dev and pppoe_release */
-static DEFINE_SPINLOCK(flush_lock);
-
/*
* PPPoE could be in the following stages:
* 1) Discovery stage (to obtain remote MAC and Session ID)
@@ -303,45 +300,48 @@ static void pppoe_flush_dev(struct net_device *dev)
write_lock_bh(&pn->hash_lock);
for (i = 0; i < PPPOE_HASH_SIZE; i++) {
struct pppox_sock *po = pn->hash_table[i];
+ struct sock *sk;
- while (po != NULL) {
- struct sock *sk;
- if (po->pppoe_dev != dev) {
+ while (po) {
+ while (po && po->pppoe_dev != dev) {
po = po->next;
- continue;
}
+
+ if (!po)
+ break;
+
sk = sk_pppox(po);
- spin_lock(&flush_lock);
- po->pppoe_dev = NULL;
- spin_unlock(&flush_lock);
- dev_put(dev);
/* We always grab the socket lock, followed by the
- * hash_lock, in that order. Since we should
- * hold the sock lock while doing any unbinding,
- * we need to release the lock we're holding.
- * Hold a reference to the sock so it doesn't disappear
- * as we're jumping between locks.
+ * hash_lock, in that order. Since we should hold the
+ * sock lock while doing any unbinding, we need to
+ * release the lock we're holding. Hold a reference to
+ * the sock so it doesn't disappear as we're jumping
+ * between locks.
*/
sock_hold(sk);
-
write_unlock_bh(&pn->hash_lock);
lock_sock(sk);
- if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
+ if (po->pppoe_dev == dev
+ && sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
pppox_unbind_sock(sk);
sk->sk_state = PPPOX_ZOMBIE;
sk->sk_state_change(sk);
+ po->pppoe_dev = NULL;
+ dev_put(dev);
}
release_sock(sk);
sock_put(sk);
- /* Restart scan at the beginning of this hash chain.
- * While the lock was dropped the chain contents may
- * have changed.
+ /* Restart the process from the start of the current
+ * hash chain. We dropped locks so the world may have
+ * change from underneath us.
*/
+
+ BUG_ON(pppoe_pernet(dev_net(dev)) == NULL);
write_lock_bh(&pn->hash_lock);
po = pn->hash_table[i];
}
@@ -388,11 +388,16 @@ static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
struct pppox_sock *po = pppox_sk(sk);
struct pppox_sock *relay_po;
+ /* Backlog receive. Semantics of backlog rcv preclude any code from
+ * executing in lock_sock()/release_sock() bounds; meaning sk->sk_state
+ * can't change.
+ */
+
if (sk->sk_state & PPPOX_BOUND) {
ppp_input(&po->chan, skb);
} else if (sk->sk_state & PPPOX_RELAY) {
- relay_po = get_item_by_addr(dev_net(po->pppoe_dev),
- &po->pppoe_relay);
+ relay_po = get_item_by_addr(sock_net(sk),
+ &po->pppoe_relay);
if (relay_po == NULL)
goto abort_kfree;
@@ -447,6 +452,10 @@ static int pppoe_rcv(struct sk_buff *skb, struct net_device *dev,
goto drop;
pn = pppoe_pernet(dev_net(dev));
+
+ /* Note that get_item does a sock_hold(), so sk_pppox(po)
+ * is known to be safe.
+ */
po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
if (!po)
goto drop;
@@ -561,6 +570,7 @@ static int pppoe_release(struct socket *sock)
struct sock *sk = sock->sk;
struct pppox_sock *po;
struct pppoe_net *pn;
+ struct net *net = NULL;
if (!sk)
return 0;
@@ -571,44 +581,28 @@ static int pppoe_release(struct socket *sock)
return -EBADF;
}
+ po = pppox_sk(sk);
+
+ if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
+ dev_put(po->pppoe_dev);
+ po->pppoe_dev = NULL;
+ }
+
pppox_unbind_sock(sk);
/* Signal the death of the socket. */
sk->sk_state = PPPOX_DEAD;
- /*
- * pppoe_flush_dev could lead to a race with
- * this routine so we use flush_lock to eliminate
- * such a case (we only need per-net specific data)
- */
- spin_lock(&flush_lock);
- po = pppox_sk(sk);
- if (!po->pppoe_dev) {
- spin_unlock(&flush_lock);
- goto out;
- }
- pn = pppoe_pernet(dev_net(po->pppoe_dev));
- spin_unlock(&flush_lock);
+ net = sock_net(sk);
+ pn = pppoe_pernet(net);
/*
* protect "po" from concurrent updates
* on pppoe_flush_dev
*/
- write_lock_bh(&pn->hash_lock);
+ delete_item(pn, po->pppoe_pa.sid, po->pppoe_pa.remote,
+ po->pppoe_ifindex);
- po = pppox_sk(sk);
- if (stage_session(po->pppoe_pa.sid))
- __delete_item(pn, po->pppoe_pa.sid, po->pppoe_pa.remote,
- po->pppoe_ifindex);
-
- if (po->pppoe_dev) {
- dev_put(po->pppoe_dev);
- po->pppoe_dev = NULL;
- }
-
- write_unlock_bh(&pn->hash_lock);
-
-out:
sock_orphan(sk);
sock->sk = NULL;
@@ -625,8 +619,9 @@ static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
struct sock *sk = sock->sk;
struct sockaddr_pppox *sp = (struct sockaddr_pppox *)uservaddr;
struct pppox_sock *po = pppox_sk(sk);
- struct net_device *dev;
+ struct net_device *dev = NULL;
struct pppoe_net *pn;
+ struct net *net = NULL;
int error;
lock_sock(sk);
@@ -652,12 +647,14 @@ static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
/* Delete the old binding */
if (stage_session(po->pppoe_pa.sid)) {
pppox_unbind_sock(sk);
+ pn = pppoe_pernet(sock_net(sk));
+ delete_item(pn, po->pppoe_pa.sid,
+ po->pppoe_pa.remote, po->pppoe_ifindex);
if (po->pppoe_dev) {
- pn = pppoe_pernet(dev_net(po->pppoe_dev));
- delete_item(pn, po->pppoe_pa.sid,
- po->pppoe_pa.remote, po->pppoe_ifindex);
dev_put(po->pppoe_dev);
+ po->pppoe_dev = NULL;
}
+
memset(sk_pppox(po) + 1, 0,
sizeof(struct pppox_sock) - sizeof(struct sock));
sk->sk_state = PPPOX_NONE;
@@ -666,16 +663,15 @@ static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
/* Re-bind in session stage only */
if (stage_session(sp->sa_addr.pppoe.sid)) {
error = -ENODEV;
- dev = dev_get_by_name(sock_net(sk), sp->sa_addr.pppoe.dev);
+ net = sock_net(sk);
+ dev = dev_get_by_name(net, sp->sa_addr.pppoe.dev);
if (!dev)
- goto end;
+ goto err_put;
po->pppoe_dev = dev;
po->pppoe_ifindex = dev->ifindex;
- pn = pppoe_pernet(dev_net(dev));
- write_lock_bh(&pn->hash_lock);
+ pn = pppoe_pernet(net);
if (!(dev->flags & IFF_UP)) {
- write_unlock_bh(&pn->hash_lock);
goto err_put;
}
@@ -683,6 +679,7 @@ static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
&sp->sa_addr.pppoe,
sizeof(struct pppoe_addr));
+ write_lock_bh(&pn->hash_lock);
error = __set_item(pn, po);
write_unlock_bh(&pn->hash_lock);
if (error < 0)
@@ -696,8 +693,11 @@ static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
po->chan.ops = &pppoe_chan_ops;
error = ppp_register_net_channel(dev_net(dev), &po->chan);
- if (error)
+ if (error) {
+ delete_item(pn, po->pppoe_pa.sid,
+ po->pppoe_pa.remote, po->pppoe_ifindex);
goto err_put;
+ }
sk->sk_state = PPPOX_CONNECTED;
}
@@ -915,6 +915,14 @@ static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
struct pppoe_hdr *ph;
int data_len = skb->len;
+ /* The higher-level PPP code (ppp_unregister_channel()) ensures the PPP
+ * xmit operations conclude prior to an unregistration call. Thus
+ * sk->sk_state cannot change, so we don't need to do lock_sock().
+ * But, we also can't do a lock_sock since that introduces a potential
+ * deadlock as we'd reverse the lock ordering used when calling
+ * ppp_unregister_channel().
+ */
+
if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
goto abort;
@@ -944,7 +952,6 @@ static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
po->pppoe_pa.remote, NULL, data_len);
dev_queue_xmit(skb);
-
return 1;
abort: