From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH] net: don't use INIT_RCU_HEAD Date: Tue, 28 Oct 2008 09:10:17 -0700 Message-ID: <20081028161017.GF6779@linux.vnet.ibm.com> References: <20081028133124.GA3006@x200.localdomain> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, netdev@vger.kernel.org To: Alexey Dobriyan Return-path: Received: from e2.ny.us.ibm.com ([32.97.182.142]:47393 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753862AbYJ1QKT (ORCPT ); Tue, 28 Oct 2008 12:10:19 -0400 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e2.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id m9SGAISK032192 for ; Tue, 28 Oct 2008 12:10:18 -0400 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id m9SGAImp079266 for ; Tue, 28 Oct 2008 12:10:18 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m9SGAHpc004896 for ; Tue, 28 Oct 2008 12:10:18 -0400 Content-Disposition: inline In-Reply-To: <20081028133124.GA3006@x200.localdomain> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Oct 28, 2008 at 04:31:24PM +0300, Alexey Dobriyan wrote: > call_rcu() will unconditionally rewrite RCU head anyway. > Applies to > struct neigh_parms > struct neigh_table > struct net > struct cipso_v4_doi > struct in_ifaddr > struct in_device > rt->u.dst Assuming that no code outside of RCU is testing the rcu_head fields... That would usually be a bad idea in any case, as call_rcu() makes no guarantee about the values of these fields after the callback is invoked. Furthermore, there have been serious proposals that would change the call_rcu() field names and layout. Therefore: Acked-by: Paul E. McKenney > Signed-off-by: Alexey Dobriyan > --- > > net/core/neighbour.c | 2 -- > net/core/net_namespace.c | 2 -- > net/ipv4/cipso_ipv4.c | 1 - > net/ipv4/devinet.c | 9 +-------- > net/ipv4/route.c | 1 - > 5 files changed, 1 insertion(+), 14 deletions(-) > > --- a/net/core/neighbour.c > +++ b/net/core/neighbour.c > @@ -1340,7 +1340,6 @@ struct neigh_parms *neigh_parms_alloc(struct net_device *dev, > if (p) { > p->tbl = tbl; > atomic_set(&p->refcnt, 1); > - INIT_RCU_HEAD(&p->rcu_head); > p->reachable_time = > neigh_rand_reach_time(p->base_reachable_time); > > @@ -1412,7 +1411,6 @@ void neigh_table_init_no_netlink(struct neigh_table *tbl) > tbl->parms.net = &init_net; > #endif > atomic_set(&tbl->parms.refcnt, 1); > - INIT_RCU_HEAD(&tbl->parms.rcu_head); > tbl->parms.reachable_time = > neigh_rand_reach_time(tbl->parms.base_reachable_time); > > --- a/net/core/net_namespace.c > +++ b/net/core/net_namespace.c > @@ -47,7 +47,6 @@ static __net_init int setup_net(struct net *net) > goto out; > > ng->len = INITIAL_NET_GEN_PTRS; > - INIT_RCU_HEAD(&ng->rcu); > rcu_assign_pointer(net->gen, ng); > > error = 0; > @@ -446,7 +445,6 @@ int net_assign_generic(struct net *net, int id, void *data) > */ > > ng->len = id; > - INIT_RCU_HEAD(&ng->rcu); > memcpy(&ng->ptr, &old_ng->ptr, old_ng->len); > > rcu_assign_pointer(net->gen, ng); > --- a/net/ipv4/cipso_ipv4.c > +++ b/net/ipv4/cipso_ipv4.c > @@ -490,7 +490,6 @@ int cipso_v4_doi_add(struct cipso_v4_doi *doi_def) > } > > atomic_set(&doi_def->refcount, 1); > - INIT_RCU_HEAD(&doi_def->rcu); > > spin_lock(&cipso_v4_doi_list_lock); > if (cipso_v4_doi_search(doi_def->doi) != NULL) > --- a/net/ipv4/devinet.c > +++ b/net/ipv4/devinet.c > @@ -112,13 +112,7 @@ static inline void devinet_sysctl_unregister(struct in_device *idev) > > static struct in_ifaddr *inet_alloc_ifa(void) > { > - struct in_ifaddr *ifa = kzalloc(sizeof(*ifa), GFP_KERNEL); > - > - if (ifa) { > - INIT_RCU_HEAD(&ifa->rcu_head); > - } > - > - return ifa; > + return kzalloc(sizeof(struct in_ifaddr), GFP_KERNEL); > } > > static void inet_rcu_free_ifa(struct rcu_head *head) > @@ -161,7 +155,6 @@ static struct in_device *inetdev_init(struct net_device *dev) > in_dev = kzalloc(sizeof(*in_dev), GFP_KERNEL); > if (!in_dev) > goto out; > - INIT_RCU_HEAD(&in_dev->rcu_head); > memcpy(&in_dev->cnf, dev_net(dev)->ipv4.devconf_dflt, > sizeof(in_dev->cnf)); > in_dev->cnf.sysctl = NULL; > --- a/net/ipv4/route.c > +++ b/net/ipv4/route.c > @@ -1386,7 +1386,6 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, > > /* Copy all the information. */ > *rt = *rth; > - INIT_RCU_HEAD(&rt->u.dst.rcu_head); > rt->u.dst.__use = 1; > atomic_set(&rt->u.dst.__refcnt, 1); > rt->u.dst.child = NULL; > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html