anycast: Some RCU conversions
- dev_get_by_flags() changed to dev_get_by_flags_rcu()
- ipv6_sock_ac_join() dont touch dev & idev refcounts
- ipv6_sock_ac_drop() dont touch dev & idev refcounts
- ipv6_sock_ac_close() dont touch dev & idev refcounts
- ipv6_dev_ac_dec() dount touch idev refcount
- ipv6_chk_acast_addr() dont touch idev refcount
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 5156b80..c319f28 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1271,8 +1271,8 @@
extern void dev_remove_pack(struct packet_type *pt);
extern void __dev_remove_pack(struct packet_type *pt);
-extern struct net_device *dev_get_by_flags(struct net *net, unsigned short flags,
- unsigned short mask);
+extern struct net_device *dev_get_by_flags_rcu(struct net *net, unsigned short flags,
+ unsigned short mask);
extern struct net_device *dev_get_by_name(struct net *net, const char *name);
extern struct net_device *dev_get_by_name_rcu(struct net *net, const char *name);
extern struct net_device *__dev_get_by_name(struct net *net, const char *name);
diff --git a/net/core/dev.c b/net/core/dev.c
index c8d1277..6f330ce 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -803,35 +803,31 @@
EXPORT_SYMBOL(dev_getfirstbyhwtype);
/**
- * dev_get_by_flags - find any device with given flags
+ * dev_get_by_flags_rcu - find any device with given flags
* @net: the applicable net namespace
* @if_flags: IFF_* values
* @mask: bitmask of bits in if_flags to check
*
* Search for any interface with the given flags. Returns NULL if a device
- * is not found or a pointer to the device. The device returned has
- * had a reference added and the pointer is safe until the user calls
- * dev_put to indicate they have finished with it.
+ * is not found or a pointer to the device. Must be called inside
+ * rcu_read_lock(), and result refcount is unchanged.
*/
-struct net_device *dev_get_by_flags(struct net *net, unsigned short if_flags,
+struct net_device *dev_get_by_flags_rcu(struct net *net, unsigned short if_flags,
unsigned short mask)
{
struct net_device *dev, *ret;
ret = NULL;
- rcu_read_lock();
for_each_netdev_rcu(net, dev) {
if (((dev->flags ^ if_flags) & mask) == 0) {
- dev_hold(dev);
ret = dev;
break;
}
}
- rcu_read_unlock();
return ret;
}
-EXPORT_SYMBOL(dev_get_by_flags);
+EXPORT_SYMBOL(dev_get_by_flags_rcu);
/**
* dev_valid_name - check if name is okay for network device
diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index b5b0705..f058fbd 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -77,41 +77,40 @@
pac->acl_next = NULL;
ipv6_addr_copy(&pac->acl_addr, addr);
+ rcu_read_lock();
if (ifindex == 0) {
struct rt6_info *rt;
rt = rt6_lookup(net, addr, NULL, 0, 0);
if (rt) {
dev = rt->rt6i_dev;
- dev_hold(dev);
dst_release(&rt->u.dst);
} else if (ishost) {
err = -EADDRNOTAVAIL;
- goto out_free_pac;
+ goto error;
} else {
/* router, no matching interface: just pick one */
-
- dev = dev_get_by_flags(net, IFF_UP, IFF_UP|IFF_LOOPBACK);
+ dev = dev_get_by_flags_rcu(net, IFF_UP,
+ IFF_UP | IFF_LOOPBACK);
}
} else
- dev = dev_get_by_index(net, ifindex);
+ dev = dev_get_by_index_rcu(net, ifindex);
if (dev == NULL) {
err = -ENODEV;
- goto out_free_pac;
+ goto error;
}
- idev = in6_dev_get(dev);
+ idev = __in6_dev_get(dev);
if (!idev) {
if (ifindex)
err = -ENODEV;
else
err = -EADDRNOTAVAIL;
- goto out_dev_put;
+ goto error;
}
/* reset ishost, now that we have a specific device */
ishost = !idev->cnf.forwarding;
- in6_dev_put(idev);
pac->acl_ifindex = dev->ifindex;
@@ -124,26 +123,22 @@
if (ishost)
err = -EADDRNOTAVAIL;
if (err)
- goto out_dev_put;
+ goto error;
}
err = ipv6_dev_ac_inc(dev, addr);
- if (err)
- goto out_dev_put;
+ if (!err) {
+ write_lock_bh(&ipv6_sk_ac_lock);
+ pac->acl_next = np->ipv6_ac_list;
+ np->ipv6_ac_list = pac;
+ write_unlock_bh(&ipv6_sk_ac_lock);
+ pac = NULL;
+ }
- write_lock_bh(&ipv6_sk_ac_lock);
- pac->acl_next = np->ipv6_ac_list;
- np->ipv6_ac_list = pac;
- write_unlock_bh(&ipv6_sk_ac_lock);
-
- dev_put(dev);
-
- return 0;
-
-out_dev_put:
- dev_put(dev);
-out_free_pac:
- sock_kfree_s(sk, pac, sizeof(*pac));
+error:
+ rcu_read_unlock();
+ if (pac)
+ sock_kfree_s(sk, pac, sizeof(*pac));
return err;
}
@@ -176,11 +171,12 @@
write_unlock_bh(&ipv6_sk_ac_lock);
- dev = dev_get_by_index(net, pac->acl_ifindex);
- if (dev) {
+ rcu_read_lock();
+ dev = dev_get_by_index_rcu(net, pac->acl_ifindex);
+ if (dev)
ipv6_dev_ac_dec(dev, &pac->acl_addr);
- dev_put(dev);
- }
+ rcu_read_unlock();
+
sock_kfree_s(sk, pac, sizeof(*pac));
return 0;
}
@@ -199,13 +195,12 @@
write_unlock_bh(&ipv6_sk_ac_lock);
prev_index = 0;
+ rcu_read_lock();
while (pac) {
struct ipv6_ac_socklist *next = pac->acl_next;
if (pac->acl_ifindex != prev_index) {
- if (dev)
- dev_put(dev);
- dev = dev_get_by_index(net, pac->acl_ifindex);
+ dev = dev_get_by_index_rcu(net, pac->acl_ifindex);
prev_index = pac->acl_ifindex;
}
if (dev)
@@ -213,8 +208,7 @@
sock_kfree_s(sk, pac, sizeof(*pac));
pac = next;
}
- if (dev)
- dev_put(dev);
+ rcu_read_unlock();
}
#if 0
@@ -363,33 +357,32 @@
return 0;
}
+/* called with rcu_read_lock() */
static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr)
{
- int ret;
- struct inet6_dev *idev = in6_dev_get(dev);
+ struct inet6_dev *idev = __in6_dev_get(dev);
+
if (idev == NULL)
return -ENODEV;
- ret = __ipv6_dev_ac_dec(idev, addr);
- in6_dev_put(idev);
- return ret;
+ return __ipv6_dev_ac_dec(idev, addr);
}
/*
* check if the interface has this anycast address
+ * called with rcu_read_lock()
*/
static int ipv6_chk_acast_dev(struct net_device *dev, struct in6_addr *addr)
{
struct inet6_dev *idev;
struct ifacaddr6 *aca;
- idev = in6_dev_get(dev);
+ idev = __in6_dev_get(dev);
if (idev) {
read_lock_bh(&idev->lock);
for (aca = idev->ac_list; aca; aca = aca->aca_next)
if (ipv6_addr_equal(&aca->aca_addr, addr))
break;
read_unlock_bh(&idev->lock);
- in6_dev_put(idev);
return aca != NULL;
}
return 0;
@@ -403,14 +396,15 @@
{
int found = 0;
- if (dev)
- return ipv6_chk_acast_dev(dev, addr);
rcu_read_lock();
- for_each_netdev_rcu(net, dev)
- if (ipv6_chk_acast_dev(dev, addr)) {
- found = 1;
- break;
- }
+ if (dev)
+ found = ipv6_chk_acast_dev(dev, addr);
+ else
+ for_each_netdev_rcu(net, dev)
+ if (ipv6_chk_acast_dev(dev, addr)) {
+ found = 1;
+ break;
+ }
rcu_read_unlock();
return found;
}