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

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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: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2010-12-05 01:23:53 +00:00
committed by David S. Miller
parent a2d4b65d47
commit 941666c2e3
5 changed files with 27 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/ipv4/arp.c
+9 -8
View File
@@ -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;
return 0;
}
if (__in_dev_get_rtnl(dev)) {
IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
if (__in_dev_get_rcu(dev)) {
IN_DEV_CONF_SET(__in_dev_get_rcu(dev), PROXY_ARP, on);
return 0;
}
return -ENXIO;
}
/* must be called with rcu_read_lock() */
static int arp_req_set_public(struct net *net, struct arpreq *r,
struct net_device *dev)
{
@@ -1033,7 +1034,7 @@ static int arp_req_set_public(struct net *net, struct arpreq *r,
if (mask && mask != htonl(0xFFFFFFFF))
return -EINVAL;
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);
if (!dev)
return -ENODEV;
@@ -1225,10 +1226,10 @@ int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
if (!(r.arp_flags & ATF_NETMASK))
((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
htonl(0xFFFFFFFFUL);
rtnl_lock();
rcu_read_lock();
if (r.arp_dev[0]) {
err = -ENODEV;
dev = __dev_get_by_name(net, r.arp_dev);
dev = dev_get_by_name_rcu(net, r.arp_dev);
if (dev == NULL)
goto out;
@@ -1252,12 +1253,12 @@ int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
break;
case SIOCGARP:
err = arp_req_get(&r, dev);
if (!err && copy_to_user(arg, &r, sizeof(r)))
err = -EFAULT;
break;
}
out:
rtnl_unlock();
rcu_read_unlock();
if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
err = -EFAULT;
return err;
}