From 941666c2e3e0f9f6a1cb5808d02352d445bd702c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Dec 2010 01:23:53 +0000 Subject: net: RCU conversion of dev_getbyhwaddr() and arp_ioctl() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: David S. Miller --- net/core/dev.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index ee605c0867e7..822b15b8d11c 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -743,34 +743,31 @@ struct net_device *dev_get_by_index(struct net *net, int ifindex) 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 * @type: media type of device * @ha: hardware address * * 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 - * rtnl semaphore. The returned device has not had its ref count increased + * is not found or a pointer to the device. The caller must hold RCU + * The returned device has not had its ref count increased * 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; - ASSERT_RTNL(); - - for_each_netdev(net, dev) + for_each_netdev_rcu(net, dev) if (dev->type == type && !memcmp(dev->dev_addr, ha, dev->addr_len)) return dev; return NULL; } -EXPORT_SYMBOL(dev_getbyhwaddr); +EXPORT_SYMBOL(dev_getbyhwaddr_rcu); struct net_device *__dev_getfirstbyhwtype(struct net *net, unsigned short type) { -- cgit v1.2.3