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decnet: RCU conversion and get rid of dev_base_lock

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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>
This commit is contained in:
Eric Dumazet 2010-10-29 03:09:24 +00:00 • committed by David S. Miller
parent e4a7b93bd5
commit fc766e4c49
8 changed files with 127 additions and 88 deletions
Download patch file Download diff file Expand all files Collapse all files

100
net/decnet/dn_dev.c
View file

@ -267,7 +267,7 @@ static int dn_forwarding_proc(ctl_table *table, int write,
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 @@ static struct dn_ifaddr *dn_dev_alloc_ifa(void)
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 @@ static int dn_dev_insert_ifa(struct dn_dev *dn_db, struct dn_ifaddr *ifa)
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 @@ static int dn_dev_insert_ifa(struct dn_dev *dn_db, struct dn_ifaddr *ifa)
}
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_insert_ifa(struct dn_dev *dn_db, struct dn_ifaddr *ifa)
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 @@ int dn_dev_ioctl(unsigned int cmd, void __user *arg)
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 @@ int dn_dev_ioctl(unsigned int cmd, void __user *arg)
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 @@ static struct dn_dev *dn_dev_by_index(int ifindex)
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 @@ static int dn_nl_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
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 @@ static int dn_nl_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
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 @@ static int dn_nl_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
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 @@ static int dn_nl_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
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 @@ done:
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 @@ static void dn_send_endnode_hello(struct net_device *dev, struct dn_ifaddr *ifa)
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 int dn_am_i_a_router(struct dn_neigh *dn, struct dn_dev *dn_db, struct dn
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_router_hello(struct net_device *dev, struct dn_ifaddr *ifa)
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 void dn_send_ptp_hello(struct net_device *dev, struct dn_ifaddr *ifa)
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 int dn_eth_up(struct net_device *dev)
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_set_timer(struct net_device *dev);
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 @@ static void dn_dev_timer_func(unsigned long arg)
} 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 @@ static struct dn_dev *dn_dev_create(struct net_device *dev, int *err)
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 @@ static struct dn_dev *dn_dev_create(struct net_device *dev, int *err)
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 @@ void dn_dev_up(struct net_device *dev)
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 @@ void dn_dev_up(struct net_device *dev)
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 @@ static void dn_dev_delete(struct net_device *dev)
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 inline int is_dn_dev(struct net_device *dev)
}
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_next(struct seq_file *seq, void *v, loff_t *pos)
}
static void dn_dev_seq_stop(struct seq_file *seq, void *v)
__releases(rcu)
__releases(RCU)
{
rcu_read_unlock();
}
@ -1340,7 +1358,7 @@ static int dn_dev_seq_show(struct seq_file *seq, void *v)
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",