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/llc/af_llc.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'net/llc') diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index 582612998211..dfd3a648a551 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -316,9 +316,9 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen) if (unlikely(addr->sllc_family != AF_LLC)) goto out; rc = -ENODEV; - rtnl_lock(); + rcu_read_lock(); 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 (!addr->sllc_arphrd) addr->sllc_arphrd = llc->dev->type; @@ -329,14 +329,15 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen) !llc_mac_match(addr->sllc_mac, llc->dev->dev_addr)) { rc = -EINVAL; - dev_put(llc->dev); llc->dev = NULL; } } } else - llc->dev = dev_getbyhwaddr(&init_net, addr->sllc_arphrd, + llc->dev = dev_getbyhwaddr_rcu(&init_net, addr->sllc_arphrd, addr->sllc_mac); - rtnl_unlock(); + if (llc->dev) + dev_hold(llc->dev); + rcu_read_unlock(); if (!llc->dev) goto out; if (!addr->sllc_sap) { -- cgit v1.2.3