decnet: RCU conversion and get rid of dev_base_lock
While tracking dev_base_lock users, I found decnet used it in
dnet_select_source(), but for a wrong purpose:
Writers only hold RTNL, not dev_base_lock, so readers must use RCU if
they cannot use RTNL.
Adds an rcu_head in struct dn_ifaddr and handle proper RCU management.
Adds __rcu annotation in dn_route as well.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/decnet/dn_dev.c b/net/decnet/dn_dev.c
index 4c409b4..0ba1563 100644
--- a/net/decnet/dn_dev.c
+++ b/net/decnet/dn_dev.c
@@ -267,7 +267,7 @@
if (table->extra1 == NULL)
return -EINVAL;
- dn_db = dev->dn_ptr;
+ dn_db = rcu_dereference_raw(dev->dn_ptr);
old = dn_db->parms.forwarding;
err = proc_dointvec(table, write, buffer, lenp, ppos);
@@ -332,14 +332,19 @@
return ifa;
}
-static __inline__ void dn_dev_free_ifa(struct dn_ifaddr *ifa)
+static void dn_dev_free_ifa_rcu(struct rcu_head *head)
{
- kfree(ifa);
+ kfree(container_of(head, struct dn_ifaddr, rcu));
}
-static void dn_dev_del_ifa(struct dn_dev *dn_db, struct dn_ifaddr **ifap, int destroy)
+static void dn_dev_free_ifa(struct dn_ifaddr *ifa)
{
- struct dn_ifaddr *ifa1 = *ifap;
+ call_rcu(&ifa->rcu, dn_dev_free_ifa_rcu);
+}
+
+static void dn_dev_del_ifa(struct dn_dev *dn_db, struct dn_ifaddr __rcu **ifap, int destroy)
+{
+ struct dn_ifaddr *ifa1 = rtnl_dereference(*ifap);
unsigned char mac_addr[6];
struct net_device *dev = dn_db->dev;
@@ -373,7 +378,9 @@
ASSERT_RTNL();
/* Check for duplicates */
- for(ifa1 = dn_db->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
+ for (ifa1 = rtnl_dereference(dn_db->ifa_list);
+ ifa1 != NULL;
+ ifa1 = rtnl_dereference(ifa1->ifa_next)) {
if (ifa1->ifa_local == ifa->ifa_local)
return -EEXIST;
}
@@ -386,7 +393,7 @@
}
ifa->ifa_next = dn_db->ifa_list;
- dn_db->ifa_list = ifa;
+ rcu_assign_pointer(dn_db->ifa_list, ifa);
dn_ifaddr_notify(RTM_NEWADDR, ifa);
blocking_notifier_call_chain(&dnaddr_chain, NETDEV_UP, ifa);
@@ -396,7 +403,7 @@
static int dn_dev_set_ifa(struct net_device *dev, struct dn_ifaddr *ifa)
{
- struct dn_dev *dn_db = dev->dn_ptr;
+ struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);
int rv;
if (dn_db == NULL) {
@@ -425,7 +432,8 @@
struct sockaddr_dn *sdn = (struct sockaddr_dn *)&ifr->ifr_addr;
struct dn_dev *dn_db;
struct net_device *dev;
- struct dn_ifaddr *ifa = NULL, **ifap = NULL;
+ struct dn_ifaddr *ifa = NULL;
+ struct dn_ifaddr __rcu **ifap = NULL;
int ret = 0;
if (copy_from_user(ifr, arg, DN_IFREQ_SIZE))
@@ -454,8 +462,10 @@
goto done;
}
- if ((dn_db = dev->dn_ptr) != NULL) {
- for (ifap = &dn_db->ifa_list; (ifa=*ifap) != NULL; ifap = &ifa->ifa_next)
+ if ((dn_db = rtnl_dereference(dev->dn_ptr)) != NULL) {
+ for (ifap = &dn_db->ifa_list;
+ (ifa = rtnl_dereference(*ifap)) != NULL;
+ ifap = &ifa->ifa_next)
if (strcmp(ifr->ifr_name, ifa->ifa_label) == 0)
break;
}
@@ -558,7 +568,7 @@
dev = __dev_get_by_index(&init_net, ifindex);
if (dev)
- dn_dev = dev->dn_ptr;
+ dn_dev = rtnl_dereference(dev->dn_ptr);
return dn_dev;
}
@@ -576,7 +586,8 @@
struct nlattr *tb[IFA_MAX+1];
struct dn_dev *dn_db;
struct ifaddrmsg *ifm;
- struct dn_ifaddr *ifa, **ifap;
+ struct dn_ifaddr *ifa;
+ struct dn_ifaddr __rcu **ifap;
int err = -EINVAL;
if (!net_eq(net, &init_net))
@@ -592,7 +603,9 @@
goto errout;
err = -EADDRNOTAVAIL;
- for (ifap = &dn_db->ifa_list; (ifa = *ifap); ifap = &ifa->ifa_next) {
+ for (ifap = &dn_db->ifa_list;
+ (ifa = rtnl_dereference(*ifap)) != NULL;
+ ifap = &ifa->ifa_next) {
if (tb[IFA_LOCAL] &&
nla_memcmp(tb[IFA_LOCAL], &ifa->ifa_local, 2))
continue;
@@ -632,7 +645,7 @@
if ((dev = __dev_get_by_index(&init_net, ifm->ifa_index)) == NULL)
return -ENODEV;
- if ((dn_db = dev->dn_ptr) == NULL) {
+ if ((dn_db = rtnl_dereference(dev->dn_ptr)) == NULL) {
dn_db = dn_dev_create(dev, &err);
if (!dn_db)
return err;
@@ -748,11 +761,11 @@
skip_naddr = 0;
}
- if ((dn_db = dev->dn_ptr) == NULL)
+ if ((dn_db = rtnl_dereference(dev->dn_ptr)) == NULL)
goto cont;
- for (ifa = dn_db->ifa_list, dn_idx = 0; ifa;
- ifa = ifa->ifa_next, dn_idx++) {
+ for (ifa = rtnl_dereference(dn_db->ifa_list), dn_idx = 0; ifa;
+ ifa = rtnl_dereference(ifa->ifa_next), dn_idx++) {
if (dn_idx < skip_naddr)
continue;
@@ -773,21 +786,22 @@
static int dn_dev_get_first(struct net_device *dev, __le16 *addr)
{
- struct dn_dev *dn_db = (struct dn_dev *)dev->dn_ptr;
+ struct dn_dev *dn_db;
struct dn_ifaddr *ifa;
int rv = -ENODEV;
+ rcu_read_lock();
+ dn_db = rcu_dereference(dev->dn_ptr);
if (dn_db == NULL)
goto out;
- rtnl_lock();
- ifa = dn_db->ifa_list;
+ ifa = rcu_dereference(dn_db->ifa_list);
if (ifa != NULL) {
*addr = ifa->ifa_local;
rv = 0;
}
- rtnl_unlock();
out:
+ rcu_read_unlock();
return rv;
}
@@ -823,7 +837,7 @@
struct endnode_hello_message *msg;
struct sk_buff *skb = NULL;
__le16 *pktlen;
- struct dn_dev *dn_db = (struct dn_dev *)dev->dn_ptr;
+ struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
if ((skb = dn_alloc_skb(NULL, sizeof(*msg), GFP_ATOMIC)) == NULL)
return;
@@ -889,7 +903,7 @@
static void dn_send_router_hello(struct net_device *dev, struct dn_ifaddr *ifa)
{
int n;
- struct dn_dev *dn_db = dev->dn_ptr;
+ struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
struct dn_neigh *dn = (struct dn_neigh *)dn_db->router;
struct sk_buff *skb;
size_t size;
@@ -960,7 +974,7 @@
static void dn_send_brd_hello(struct net_device *dev, struct dn_ifaddr *ifa)
{
- struct dn_dev *dn_db = (struct dn_dev *)dev->dn_ptr;
+ struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
if (dn_db->parms.forwarding == 0)
dn_send_endnode_hello(dev, ifa);
@@ -998,7 +1012,7 @@
static int dn_eth_up(struct net_device *dev)
{
- struct dn_dev *dn_db = dev->dn_ptr;
+ struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
if (dn_db->parms.forwarding == 0)
dev_mc_add(dev, dn_rt_all_end_mcast);
@@ -1012,7 +1026,7 @@
static void dn_eth_down(struct net_device *dev)
{
- struct dn_dev *dn_db = dev->dn_ptr;
+ struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
if (dn_db->parms.forwarding == 0)
dev_mc_del(dev, dn_rt_all_end_mcast);
@@ -1025,12 +1039,16 @@
static void dn_dev_timer_func(unsigned long arg)
{
struct net_device *dev = (struct net_device *)arg;
- struct dn_dev *dn_db = dev->dn_ptr;
+ struct dn_dev *dn_db;
struct dn_ifaddr *ifa;
+ rcu_read_lock();
+ dn_db = rcu_dereference(dev->dn_ptr);
if (dn_db->t3 <= dn_db->parms.t2) {
if (dn_db->parms.timer3) {
- for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
+ for (ifa = rcu_dereference(dn_db->ifa_list);
+ ifa;
+ ifa = rcu_dereference(ifa->ifa_next)) {
if (!(ifa->ifa_flags & IFA_F_SECONDARY))
dn_db->parms.timer3(dev, ifa);
}
@@ -1039,13 +1057,13 @@
} else {
dn_db->t3 -= dn_db->parms.t2;
}
-
+ rcu_read_unlock();
dn_dev_set_timer(dev);
}
static void dn_dev_set_timer(struct net_device *dev)
{
- struct dn_dev *dn_db = dev->dn_ptr;
+ struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
if (dn_db->parms.t2 > dn_db->parms.t3)
dn_db->parms.t2 = dn_db->parms.t3;
@@ -1077,8 +1095,8 @@
return NULL;
memcpy(&dn_db->parms, p, sizeof(struct dn_dev_parms));
- smp_wmb();
- dev->dn_ptr = dn_db;
+
+ rcu_assign_pointer(dev->dn_ptr, dn_db);
dn_db->dev = dev;
init_timer(&dn_db->timer);
@@ -1086,7 +1104,7 @@
dn_db->neigh_parms = neigh_parms_alloc(dev, &dn_neigh_table);
if (!dn_db->neigh_parms) {
- dev->dn_ptr = NULL;
+ rcu_assign_pointer(dev->dn_ptr, NULL);
kfree(dn_db);
return NULL;
}
@@ -1125,7 +1143,7 @@
struct dn_ifaddr *ifa;
__le16 addr = decnet_address;
int maybe_default = 0;
- struct dn_dev *dn_db = (struct dn_dev *)dev->dn_ptr;
+ struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);
if ((dev->type != ARPHRD_ETHER) && (dev->type != ARPHRD_LOOPBACK))
return;
@@ -1176,7 +1194,7 @@
static void dn_dev_delete(struct net_device *dev)
{
- struct dn_dev *dn_db = dev->dn_ptr;
+ struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);
if (dn_db == NULL)
return;
@@ -1204,13 +1222,13 @@
void dn_dev_down(struct net_device *dev)
{
- struct dn_dev *dn_db = dev->dn_ptr;
+ struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);
struct dn_ifaddr *ifa;
if (dn_db == NULL)
return;
- while((ifa = dn_db->ifa_list) != NULL) {
+ while ((ifa = rtnl_dereference(dn_db->ifa_list)) != NULL) {
dn_dev_del_ifa(dn_db, &dn_db->ifa_list, 0);
dn_dev_free_ifa(ifa);
}
@@ -1270,7 +1288,7 @@
}
static void *dn_dev_seq_start(struct seq_file *seq, loff_t *pos)
- __acquires(rcu)
+ __acquires(RCU)
{
int i;
struct net_device *dev;
@@ -1313,7 +1331,7 @@
}
static void dn_dev_seq_stop(struct seq_file *seq, void *v)
- __releases(rcu)
+ __releases(RCU)
{
rcu_read_unlock();
}
@@ -1340,7 +1358,7 @@
struct net_device *dev = v;
char peer_buf[DN_ASCBUF_LEN];
char router_buf[DN_ASCBUF_LEN];
- struct dn_dev *dn_db = dev->dn_ptr;
+ struct dn_dev *dn_db = rcu_dereference(dev->dn_ptr);
seq_printf(seq, "%-8s %1s %04u %04u %04lu %04lu"
" %04hu %03d %02x %-10s %-7s %-7s\n",