Commit 941666c2 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

net: RCU conversion of dev_getbyhwaddr() and arp_ioctl()

Le dimanche 05 décembre 2010 à 09:19 +0100, Eric Dumazet a écrit :

> Hmm..
>
> If somebody can explain why RTNL is held in arp_ioctl() (and therefore
> in arp_req_delete()), we might first remove RTNL use in arp_ioctl() so
> that your patch can be applied.
>
> Right now it is not good, because RTNL wont be necessarly held when you
> are going to call arp_invalidate() ?

While doing this analysis, I found a refcount bug in llc, I'll send a
patch for net-2.6

Meanwhile, here is the patch for net-next-2.6

Your patch then can be applied after mine.

Thanks

[PATCH] net: RCU conversion of dev_getbyhwaddr() and arp_ioctl()

dev_getbyhwaddr() was called under RTNL.

Rename it to dev_getbyhwaddr_rcu() and change all its caller to now use
RCU locking instead of RTNL.

Change arp_ioctl() to use RCU instead of RTNL locking.

Note: this fix a dev refcount bug in llc
Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a2d4b65d
...@@ -1360,7 +1360,8 @@ static inline struct net_device *first_net_device(struct net *net) ...@@ -1360,7 +1360,8 @@ static inline struct net_device *first_net_device(struct net *net)
extern int netdev_boot_setup_check(struct net_device *dev); extern int netdev_boot_setup_check(struct net_device *dev);
extern unsigned long netdev_boot_base(const char *prefix, int unit); extern unsigned long netdev_boot_base(const char *prefix, int unit);
extern struct net_device *dev_getbyhwaddr(struct net *net, unsigned short type, char *hwaddr); extern struct net_device *dev_getbyhwaddr_rcu(struct net *net, unsigned short type,
const char *hwaddr);
extern struct net_device *dev_getfirstbyhwtype(struct net *net, unsigned short type); extern struct net_device *dev_getfirstbyhwtype(struct net *net, unsigned short type);
extern struct net_device *__dev_getfirstbyhwtype(struct net *net, unsigned short type); extern struct net_device *__dev_getfirstbyhwtype(struct net *net, unsigned short type);
extern void dev_add_pack(struct packet_type *pt); extern void dev_add_pack(struct packet_type *pt);
......
...@@ -743,34 +743,31 @@ struct net_device *dev_get_by_index(struct net *net, int ifindex) ...@@ -743,34 +743,31 @@ struct net_device *dev_get_by_index(struct net *net, int ifindex)
EXPORT_SYMBOL(dev_get_by_index); EXPORT_SYMBOL(dev_get_by_index);
/** /**
* dev_getbyhwaddr - find a device by its hardware address * dev_getbyhwaddr_rcu - find a device by its hardware address
* @net: the applicable net namespace * @net: the applicable net namespace
* @type: media type of device * @type: media type of device
* @ha: hardware address * @ha: hardware address
* *
* Search for an interface by MAC address. Returns NULL if the device * Search for an interface by MAC address. Returns NULL if the device
* is not found or a pointer to the device. The caller must hold the * is not found or a pointer to the device. The caller must hold RCU
* rtnl semaphore. The returned device has not had its ref count increased * The returned device has not had its ref count increased
* and the caller must therefore be careful about locking * and the caller must therefore be careful about locking
* *
* BUGS:
* If the API was consistent this would be __dev_get_by_hwaddr
*/ */
struct net_device *dev_getbyhwaddr(struct net *net, unsigned short type, char *ha) struct net_device *dev_getbyhwaddr_rcu(struct net *net, unsigned short type,
const char *ha)
{ {
struct net_device *dev; struct net_device *dev;
ASSERT_RTNL(); for_each_netdev_rcu(net, dev)
for_each_netdev(net, dev)
if (dev->type == type && if (dev->type == type &&
!memcmp(dev->dev_addr, ha, dev->addr_len)) !memcmp(dev->dev_addr, ha, dev->addr_len))
return dev; return dev;
return NULL; return NULL;
} }
EXPORT_SYMBOL(dev_getbyhwaddr); EXPORT_SYMBOL(dev_getbyhwaddr_rcu);
struct net_device *__dev_getfirstbyhwtype(struct net *net, unsigned short type) struct net_device *__dev_getfirstbyhwtype(struct net *net, unsigned short type)
{ {
......
...@@ -52,11 +52,11 @@ struct net_device *ieee802154_get_dev(struct net *net, ...@@ -52,11 +52,11 @@ struct net_device *ieee802154_get_dev(struct net *net,
switch (addr->addr_type) { switch (addr->addr_type) {
case IEEE802154_ADDR_LONG: case IEEE802154_ADDR_LONG:
rtnl_lock(); rcu_read_lock();
dev = dev_getbyhwaddr(net, ARPHRD_IEEE802154, addr->hwaddr); dev = dev_getbyhwaddr_rcu(net, ARPHRD_IEEE802154, addr->hwaddr);
if (dev) if (dev)
dev_hold(dev); dev_hold(dev);
rtnl_unlock(); rcu_read_unlock();
break; break;
case IEEE802154_ADDR_SHORT: case IEEE802154_ADDR_SHORT:
if (addr->pan_id == 0xffff || if (addr->pan_id == 0xffff ||
......
...@@ -1017,13 +1017,14 @@ static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) ...@@ -1017,13 +1017,14 @@ static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
return 0; return 0;
} }
if (__in_dev_get_rtnl(dev)) { if (__in_dev_get_rcu(dev)) {
IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); IN_DEV_CONF_SET(__in_dev_get_rcu(dev), PROXY_ARP, on);
return 0; return 0;
} }
return -ENXIO; return -ENXIO;
} }
/* must be called with rcu_read_lock() */
static int arp_req_set_public(struct net *net, struct arpreq *r, static int arp_req_set_public(struct net *net, struct arpreq *r,
struct net_device *dev) struct net_device *dev)
{ {
...@@ -1033,7 +1034,7 @@ static int arp_req_set_public(struct net *net, struct arpreq *r, ...@@ -1033,7 +1034,7 @@ static int arp_req_set_public(struct net *net, struct arpreq *r,
if (mask && mask != htonl(0xFFFFFFFF)) if (mask && mask != htonl(0xFFFFFFFF))
return -EINVAL; return -EINVAL;
if (!dev && (r->arp_flags & ATF_COM)) { if (!dev && (r->arp_flags & ATF_COM)) {
dev = dev_getbyhwaddr(net, r->arp_ha.sa_family, dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
r->arp_ha.sa_data); r->arp_ha.sa_data);
if (!dev) if (!dev)
return -ENODEV; return -ENODEV;
...@@ -1225,10 +1226,10 @@ int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) ...@@ -1225,10 +1226,10 @@ int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
if (!(r.arp_flags & ATF_NETMASK)) if (!(r.arp_flags & ATF_NETMASK))
((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
htonl(0xFFFFFFFFUL); htonl(0xFFFFFFFFUL);
rtnl_lock(); rcu_read_lock();
if (r.arp_dev[0]) { if (r.arp_dev[0]) {
err = -ENODEV; err = -ENODEV;
dev = __dev_get_by_name(net, r.arp_dev); dev = dev_get_by_name_rcu(net, r.arp_dev);
if (dev == NULL) if (dev == NULL)
goto out; goto out;
...@@ -1252,12 +1253,12 @@ int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) ...@@ -1252,12 +1253,12 @@ int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
break; break;
case SIOCGARP: case SIOCGARP:
err = arp_req_get(&r, dev); err = arp_req_get(&r, dev);
if (!err && copy_to_user(arg, &r, sizeof(r)))
err = -EFAULT;
break; break;
} }
out: out:
rtnl_unlock(); rcu_read_unlock();
if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
err = -EFAULT;
return err; return err;
} }
......
...@@ -316,9 +316,9 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen) ...@@ -316,9 +316,9 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
if (unlikely(addr->sllc_family != AF_LLC)) if (unlikely(addr->sllc_family != AF_LLC))
goto out; goto out;
rc = -ENODEV; rc = -ENODEV;
rtnl_lock(); rcu_read_lock();
if (sk->sk_bound_dev_if) { if (sk->sk_bound_dev_if) {
llc->dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if); llc->dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if);
if (llc->dev) { if (llc->dev) {
if (!addr->sllc_arphrd) if (!addr->sllc_arphrd)
addr->sllc_arphrd = llc->dev->type; addr->sllc_arphrd = llc->dev->type;
...@@ -329,14 +329,15 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen) ...@@ -329,14 +329,15 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
!llc_mac_match(addr->sllc_mac, !llc_mac_match(addr->sllc_mac,
llc->dev->dev_addr)) { llc->dev->dev_addr)) {
rc = -EINVAL; rc = -EINVAL;
dev_put(llc->dev);
llc->dev = NULL; llc->dev = NULL;
} }
} }
} else } else
llc->dev = dev_getbyhwaddr(&init_net, addr->sllc_arphrd, llc->dev = dev_getbyhwaddr_rcu(&init_net, addr->sllc_arphrd,
addr->sllc_mac); addr->sllc_mac);
rtnl_unlock(); if (llc->dev)
dev_hold(llc->dev);
rcu_read_unlock();
if (!llc->dev) if (!llc->dev)
goto out; goto out;
if (!addr->sllc_sap) { if (!addr->sllc_sap) {
......
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