Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757517AbZDPR70 (ORCPT ); Thu, 16 Apr 2009 13:59:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753781AbZDPR7H (ORCPT ); Thu, 16 Apr 2009 13:59:07 -0400 Received: from e9.ny.us.ibm.com ([32.97.182.139]:43192 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752621AbZDPR7B (ORCPT ); Thu, 16 Apr 2009 13:59:01 -0400 Date: Thu, 16 Apr 2009 10:58:50 -0700 From: "Paul E. McKenney" To: Eric Dumazet Cc: Patrick McHardy , Stephen Hemminger , Linus Torvalds , David Miller , jeff.chua.linux@gmail.com, paulus@samba.org, mingo@elte.hu, laijs@cn.fujitsu.com, jengelh@medozas.de, r000n@r000n.net, linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, netdev@vger.kernel.org, benh@kernel.crashing.org Subject: Re: [PATCH] netfilter: use per-cpu recursive spinlock (v6) Message-ID: <20090416175850.GH6924@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20090415135526.2afc4d18@nehalam> <49E64C91.5020708@cosmosbay.com> <20090415.164811.19905145.davem@davemloft.net> <20090415170111.6e1ca264@nehalam> <20090415174551.529d241c@nehalam> <49E6BBA9.2030701@cosmosbay.com> <49E7384B.5020707@trash.net> <20090416144748.GB6924@linux.vnet.ibm.com> <49E75876.10509@cosmosbay.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <49E75876.10509@cosmosbay.com> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 27946 Lines: 945 On Thu, Apr 16, 2009 at 06:10:30PM +0200, Eric Dumazet wrote: > Paul E. McKenney a ?crit : > > > Well, we don't really need an rwlock, especially given that we really > > don't want two "readers" incrementing the same counter concurrently. > > > > A safer approach would be to maintain a flag in the task structure > > tracking which (if any) of the per-CPU locks you hold. Also maintain > > a recursion-depth counter. If the flag says you don't already hold > > the lock, set it and acquire the lock. Either way, increment the > > recursion-depth counter: > > > > if (current->netfilter_lock_held != cur_cpu) { > > BUG_ON(current->netfilter_lock_held != CPU_NONE); > > spin_lock(per_cpu(..., cur_cpu)); > > current->netfilter_lock_held = cur_cpu; > > } > > current->netfilter_lock_nesting++; > > > > And reverse the process to unlock: > > > > if (--current->netfilter_lock_nesting == 0) { > > spin_unlock(per_cpu(..., cur_cpu)); > > current->netfilter_lock_held = CPU_NONE; > > } > > > > Yes, you are right, we can avoid rwlock, but use a 'recursive' lock > or spin_trylock() > > We can use one counter close to the spinlock, > no need to add one or two fields to every "thread_info" > > struct rec_lock { > spinlock_t lock; > int count; > }; > static DEFINE_PER_CPU(struct rec_lock, ip_tables_lock); Yep, much better approach! > I also considered using regular spinlocks and spin_trylock() to "detect" > the recurse case without a global counter. > > lock : > local_bh_disable(); > int locked = spin_trylock(&__get_cpu_var(arp_tables_lock); Hmmm... What happens if some other CPU is actually holding the lock? For example, the updater? > unlock: > > if (likely(locked)) > spin_unlock(&__get_cpu_var(arp_tables_lock)); > local_bh_enable(); > > But we would lose some runtime features, I dont feel comfortable about > this trylock version. What others people think ? I do not believe that it actually works. I much prefer your earlier idea of associating a counter with the lock. But an owner field is also required, please see below. Or please let me know what I am missing. Thanx, Paul > Here is the resulting patch, based on Stephen v4 > > (Not sure we *need* recursive spinlock for the arp_tables, but it seems > better to have an uniform implementation) > > > [PATCH] netfilter: use per-cpu recursive spinlock (v6) > > Yet another alternative version of ip/ip6/arp tables locking using > per-cpu locks. This avoids the overhead of synchronize_net() during > update but still removes the expensive rwlock in earlier versions. > > The idea for this came from an earlier version done by Eric Dumazet. > Locking is done per-cpu, the fast path locks on the current cpu > and updates counters. The slow case involves acquiring the locks on > all cpu's. > > The mutex that was added for 2.6.30 in xt_table is unnecessary since > there already is a mutex for xt[af].mutex that is held. > > We have to use recursive spinlocks because netfilter can sometimes > nest several calls to ipt_do_table() for a given cpu. > > Signed-off-by: Stephen Hemminger Signed-off-by: Eric Dumazet > --- > include/linux/netfilter/x_tables.h | 5 - > net/ipv4/netfilter/arp_tables.c | 131 +++++++++------------------ > net/ipv4/netfilter/ip_tables.c | 130 +++++++++----------------- > net/ipv6/netfilter/ip6_tables.c | 127 +++++++++----------------- > net/netfilter/x_tables.c | 26 ----- > 5 files changed, 138 insertions(+), 281 deletions(-) > > diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h > index 7b1a652..1ff1a76 100644 > --- a/include/linux/netfilter/x_tables.h > +++ b/include/linux/netfilter/x_tables.h > @@ -354,9 +354,6 @@ struct xt_table > /* What hooks you will enter on */ > unsigned int valid_hooks; > > - /* Lock for the curtain */ > - struct mutex lock; > - > /* Man behind the curtain... */ > struct xt_table_info *private; > > @@ -434,8 +431,6 @@ extern void xt_proto_fini(struct net *net, u_int8_t af); > > extern struct xt_table_info *xt_alloc_table_info(unsigned int size); > extern void xt_free_table_info(struct xt_table_info *info); > -extern void xt_table_entry_swap_rcu(struct xt_table_info *old, > - struct xt_table_info *new); > > /* > * This helper is performance critical and must be inlined > diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c > index 5ba533d..9f935f2 100644 > --- a/net/ipv4/netfilter/arp_tables.c > +++ b/net/ipv4/netfilter/arp_tables.c > @@ -231,6 +231,12 @@ static inline struct arpt_entry *get_entry(void *base, unsigned int offset) > return (struct arpt_entry *)(base + offset); > } > > +struct rec_lock { > + spinlock_t lock; > + int count; /* recursion count */ We also need an owner field: int owner; > +}; > +static DEFINE_PER_CPU(struct rec_lock, arp_tables_lock); > + > unsigned int arpt_do_table(struct sk_buff *skb, > unsigned int hook, > const struct net_device *in, > @@ -246,6 +252,7 @@ unsigned int arpt_do_table(struct sk_buff *skb, > void *table_base; > const struct xt_table_info *private; > struct xt_target_param tgpar; > + struct rec_lock *rl; > > if (!pskb_may_pull(skb, arp_hdr_len(skb->dev))) > return NF_DROP; > @@ -255,7 +262,12 @@ unsigned int arpt_do_table(struct sk_buff *skb, > > rcu_read_lock_bh(); > private = rcu_dereference(table->private); > - table_base = rcu_dereference(private->entries[smp_processor_id()]); > + > + rl = &__get_cpu_var(arp_tables_lock); > + if (likely(rl->count++ == 0)) > + spin_lock(&rl->lock); But if some other CPU holds the lock, this code would fail to wait for that other CPU to release the lock, right? It also might corrupt the rl->count field due to two CPUs accessing it concurrently non-atomically. I suggest the following, preferably in a function or macro or something: cur_cpu = smp_processor_id(); if (likely(rl->owner != cur_cpu) { spin_lock(&rl->lock); rl->owner = smp_processor_id(); rl->count = 1; } else { rl->count++; } And the inverse for unlock. Or am I missing something subtle? > + > + table_base = private->entries[smp_processor_id()]; > > e = get_entry(table_base, private->hook_entry[hook]); > back = get_entry(table_base, private->underflow[hook]); > @@ -273,6 +285,7 @@ unsigned int arpt_do_table(struct sk_buff *skb, > > hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) + > (2 * skb->dev->addr_len); > + > ADD_COUNTER(e->counters, hdr_len, 1); > > t = arpt_get_target(e); > @@ -328,7 +341,8 @@ unsigned int arpt_do_table(struct sk_buff *skb, > e = (void *)e + e->next_offset; > } > } while (!hotdrop); > - > + if (likely(--rl->count == 0)) > + spin_unlock(&rl->lock); > rcu_read_unlock_bh(); > > if (hotdrop) > @@ -716,74 +730,25 @@ static void get_counters(const struct xt_table_info *t, > curcpu = raw_smp_processor_id(); > > i = 0; > + spin_lock_bh(&per_cpu(arp_tables_lock, curcpu).lock); > ARPT_ENTRY_ITERATE(t->entries[curcpu], > t->size, > set_entry_to_counter, > counters, > &i); > + spin_unlock_bh(&per_cpu(arp_tables_lock, curcpu).lock); > > for_each_possible_cpu(cpu) { > if (cpu == curcpu) > continue; > i = 0; > + spin_lock_bh(&per_cpu(arp_tables_lock, cpu).lock); > ARPT_ENTRY_ITERATE(t->entries[cpu], > t->size, > add_entry_to_counter, > counters, > &i); > - } > -} > - > - > -/* We're lazy, and add to the first CPU; overflow works its fey magic > - * and everything is OK. */ > -static int > -add_counter_to_entry(struct arpt_entry *e, > - const struct xt_counters addme[], > - unsigned int *i) > -{ > - ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt); > - > - (*i)++; > - return 0; > -} > - > -/* Take values from counters and add them back onto the current cpu */ > -static void put_counters(struct xt_table_info *t, > - const struct xt_counters counters[]) > -{ > - unsigned int i, cpu; > - > - local_bh_disable(); > - cpu = smp_processor_id(); > - i = 0; > - ARPT_ENTRY_ITERATE(t->entries[cpu], > - t->size, > - add_counter_to_entry, > - counters, > - &i); > - local_bh_enable(); > -} > - > -static inline int > -zero_entry_counter(struct arpt_entry *e, void *arg) > -{ > - e->counters.bcnt = 0; > - e->counters.pcnt = 0; > - return 0; > -} > - > -static void > -clone_counters(struct xt_table_info *newinfo, const struct xt_table_info *info) > -{ > - unsigned int cpu; > - const void *loc_cpu_entry = info->entries[raw_smp_processor_id()]; > - > - memcpy(newinfo, info, offsetof(struct xt_table_info, entries)); > - for_each_possible_cpu(cpu) { > - memcpy(newinfo->entries[cpu], loc_cpu_entry, info->size); > - ARPT_ENTRY_ITERATE(newinfo->entries[cpu], newinfo->size, > - zero_entry_counter, NULL); > + spin_unlock_bh(&per_cpu(arp_tables_lock, cpu).lock); > } > } > > @@ -792,7 +757,6 @@ static struct xt_counters *alloc_counters(struct xt_table *table) > unsigned int countersize; > struct xt_counters *counters; > struct xt_table_info *private = table->private; > - struct xt_table_info *info; > > /* We need atomic snapshot of counters: rest doesn't change > * (other than comefrom, which userspace doesn't care > @@ -802,30 +766,11 @@ static struct xt_counters *alloc_counters(struct xt_table *table) > counters = vmalloc_node(countersize, numa_node_id()); > > if (counters == NULL) > - goto nomem; > - > - info = xt_alloc_table_info(private->size); > - if (!info) > - goto free_counters; > - > - clone_counters(info, private); > + return ERR_PTR(-ENOMEM); > > - mutex_lock(&table->lock); > - xt_table_entry_swap_rcu(private, info); > - synchronize_net(); /* Wait until smoke has cleared */ > - > - get_counters(info, counters); > - put_counters(private, counters); > - mutex_unlock(&table->lock); > - > - xt_free_table_info(info); > + get_counters(private, counters); > > return counters; > - > - free_counters: > - vfree(counters); > - nomem: > - return ERR_PTR(-ENOMEM); > } > > static int copy_entries_to_user(unsigned int total_size, > @@ -1165,6 +1110,19 @@ static int do_replace(struct net *net, void __user *user, unsigned int len) > return ret; > } > > +/* We're lazy, and add to the first CPU; overflow works its fey magic > + * and everything is OK. */ > +static int > +add_counter_to_entry(struct arpt_entry *e, > + const struct xt_counters addme[], > + unsigned int *i) > +{ > + ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt); > + > + (*i)++; > + return 0; > +} > + > static int do_add_counters(struct net *net, void __user *user, unsigned int len, > int compat) > { > @@ -1173,7 +1131,7 @@ static int do_add_counters(struct net *net, void __user *user, unsigned int len, > struct xt_counters *paddc; > unsigned int num_counters; > const char *name; > - int size; > + int cpu, size; > void *ptmp; > struct xt_table *t; > const struct xt_table_info *private; > @@ -1224,25 +1182,25 @@ static int do_add_counters(struct net *net, void __user *user, unsigned int len, > goto free; > } > > - mutex_lock(&t->lock); > private = t->private; > if (private->number != num_counters) { > ret = -EINVAL; > goto unlock_up_free; > } > > - preempt_disable(); > - i = 0; > /* Choose the copy that is on our node */ > - loc_cpu_entry = private->entries[smp_processor_id()]; > + cpu = raw_smp_processor_id(); > + spin_lock_bh(&per_cpu(arp_tables_lock, cpu).lock); > + loc_cpu_entry = private->entries[cpu]; > + i = 0; > ARPT_ENTRY_ITERATE(loc_cpu_entry, > private->size, > add_counter_to_entry, > paddc, > &i); > - preempt_enable(); > + spin_unlock_bh(&per_cpu(arp_tables_lock, cpu).lock); > + > unlock_up_free: > - mutex_unlock(&t->lock); > > xt_table_unlock(t); > module_put(t->me); > @@ -1923,7 +1881,10 @@ static struct pernet_operations arp_tables_net_ops = { > > static int __init arp_tables_init(void) > { > - int ret; > + int cpu, ret; > + > + for_each_possible_cpu(cpu) > + spin_lock_init(&per_cpu(arp_tables_lock, cpu).lock); > > ret = register_pernet_subsys(&arp_tables_net_ops); > if (ret < 0) > diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c > index 810c0b6..1368b6d 100644 > --- a/net/ipv4/netfilter/ip_tables.c > +++ b/net/ipv4/netfilter/ip_tables.c > @@ -297,6 +297,12 @@ static void trace_packet(struct sk_buff *skb, > } > #endif > > +struct rec_lock { > + spinlock_t lock; > + int count; /* recursion count */ > +}; > +static DEFINE_PER_CPU(struct rec_lock, ip_tables_lock); > + > /* Returns one of the generic firewall policies, like NF_ACCEPT. */ > unsigned int > ipt_do_table(struct sk_buff *skb, > @@ -317,6 +323,7 @@ ipt_do_table(struct sk_buff *skb, > struct xt_table_info *private; > struct xt_match_param mtpar; > struct xt_target_param tgpar; > + struct rec_lock *rl; > > /* Initialization */ > ip = ip_hdr(skb); > @@ -341,7 +348,12 @@ ipt_do_table(struct sk_buff *skb, > > rcu_read_lock_bh(); > private = rcu_dereference(table->private); > - table_base = rcu_dereference(private->entries[smp_processor_id()]); > + > + rl = &__get_cpu_var(ip_tables_lock); > + if (likely(rl->count++ == 0)) > + spin_lock(&rl->lock); > + > + table_base = private->entries[smp_processor_id()]; > > e = get_entry(table_base, private->hook_entry[hook]); > > @@ -436,7 +448,8 @@ ipt_do_table(struct sk_buff *skb, > e = (void *)e + e->next_offset; > } > } while (!hotdrop); > - > + if (likely(--rl->count == 0)) > + spin_unlock(&rl->lock); > rcu_read_unlock_bh(); > > #ifdef DEBUG_ALLOW_ALL > @@ -902,75 +915,25 @@ get_counters(const struct xt_table_info *t, > curcpu = raw_smp_processor_id(); > > i = 0; > + spin_lock_bh(&per_cpu(ip_tables_lock, curcpu).lock); > IPT_ENTRY_ITERATE(t->entries[curcpu], > t->size, > set_entry_to_counter, > counters, > &i); > + spin_unlock_bh(&per_cpu(ip_tables_lock, curcpu).lock); > > for_each_possible_cpu(cpu) { > if (cpu == curcpu) > continue; > i = 0; > + spin_lock_bh(&per_cpu(ip_tables_lock, cpu).lock); > IPT_ENTRY_ITERATE(t->entries[cpu], > t->size, > add_entry_to_counter, > counters, > &i); > - } > - > -} > - > -/* We're lazy, and add to the first CPU; overflow works its fey magic > - * and everything is OK. */ > -static int > -add_counter_to_entry(struct ipt_entry *e, > - const struct xt_counters addme[], > - unsigned int *i) > -{ > - ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt); > - > - (*i)++; > - return 0; > -} > - > -/* Take values from counters and add them back onto the current cpu */ > -static void put_counters(struct xt_table_info *t, > - const struct xt_counters counters[]) > -{ > - unsigned int i, cpu; > - > - local_bh_disable(); > - cpu = smp_processor_id(); > - i = 0; > - IPT_ENTRY_ITERATE(t->entries[cpu], > - t->size, > - add_counter_to_entry, > - counters, > - &i); > - local_bh_enable(); > -} > - > - > -static inline int > -zero_entry_counter(struct ipt_entry *e, void *arg) > -{ > - e->counters.bcnt = 0; > - e->counters.pcnt = 0; > - return 0; > -} > - > -static void > -clone_counters(struct xt_table_info *newinfo, const struct xt_table_info *info) > -{ > - unsigned int cpu; > - const void *loc_cpu_entry = info->entries[raw_smp_processor_id()]; > - > - memcpy(newinfo, info, offsetof(struct xt_table_info, entries)); > - for_each_possible_cpu(cpu) { > - memcpy(newinfo->entries[cpu], loc_cpu_entry, info->size); > - IPT_ENTRY_ITERATE(newinfo->entries[cpu], newinfo->size, > - zero_entry_counter, NULL); > + spin_unlock_bh(&per_cpu(ip_tables_lock, cpu).lock); > } > } > > @@ -979,7 +942,6 @@ static struct xt_counters * alloc_counters(struct xt_table *table) > unsigned int countersize; > struct xt_counters *counters; > struct xt_table_info *private = table->private; > - struct xt_table_info *info; > > /* We need atomic snapshot of counters: rest doesn't change > (other than comefrom, which userspace doesn't care > @@ -988,30 +950,11 @@ static struct xt_counters * alloc_counters(struct xt_table *table) > counters = vmalloc_node(countersize, numa_node_id()); > > if (counters == NULL) > - goto nomem; > - > - info = xt_alloc_table_info(private->size); > - if (!info) > - goto free_counters; > - > - clone_counters(info, private); > - > - mutex_lock(&table->lock); > - xt_table_entry_swap_rcu(private, info); > - synchronize_net(); /* Wait until smoke has cleared */ > + return ERR_PTR(-ENOMEM); > > - get_counters(info, counters); > - put_counters(private, counters); > - mutex_unlock(&table->lock); > - > - xt_free_table_info(info); > + get_counters(private, counters); > > return counters; > - > - free_counters: > - vfree(counters); > - nomem: > - return ERR_PTR(-ENOMEM); > } > > static int > @@ -1377,6 +1320,18 @@ do_replace(struct net *net, void __user *user, unsigned int len) > return ret; > } > > +/* We're lazy, and add to the first CPU; overflow works its fey magic > + * and everything is OK. */ > +static int > +add_counter_to_entry(struct ipt_entry *e, > + const struct xt_counters addme[], > + unsigned int *i) > +{ > + ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt); > + > + (*i)++; > + return 0; > +} > > static int > do_add_counters(struct net *net, void __user *user, unsigned int len, int compat) > @@ -1386,7 +1341,7 @@ do_add_counters(struct net *net, void __user *user, unsigned int len, int compat > struct xt_counters *paddc; > unsigned int num_counters; > const char *name; > - int size; > + int cpu, size; > void *ptmp; > struct xt_table *t; > const struct xt_table_info *private; > @@ -1437,25 +1392,25 @@ do_add_counters(struct net *net, void __user *user, unsigned int len, int compat > goto free; > } > > - mutex_lock(&t->lock); > private = t->private; > if (private->number != num_counters) { > ret = -EINVAL; > goto unlock_up_free; > } > > - preempt_disable(); > - i = 0; > /* Choose the copy that is on our node */ > - loc_cpu_entry = private->entries[raw_smp_processor_id()]; > + cpu = raw_smp_processor_id(); > + spin_lock_bh(&per_cpu(ip_tables_lock, cpu).lock); > + loc_cpu_entry = private->entries[cpu]; > + i = 0; > IPT_ENTRY_ITERATE(loc_cpu_entry, > private->size, > add_counter_to_entry, > paddc, > &i); > - preempt_enable(); > + spin_unlock_bh(&per_cpu(ip_tables_lock, cpu).lock); > + > unlock_up_free: > - mutex_unlock(&t->lock); > xt_table_unlock(t); > module_put(t->me); > free: > @@ -2272,7 +2227,10 @@ static struct pernet_operations ip_tables_net_ops = { > > static int __init ip_tables_init(void) > { > - int ret; > + int cpu, ret; > + > + for_each_possible_cpu(cpu) > + spin_lock_init(&per_cpu(ip_tables_lock, cpu).lock); > > ret = register_pernet_subsys(&ip_tables_net_ops); > if (ret < 0) > diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c > index 800ae85..5b03479 100644 > --- a/net/ipv6/netfilter/ip6_tables.c > +++ b/net/ipv6/netfilter/ip6_tables.c > @@ -329,6 +329,12 @@ static void trace_packet(struct sk_buff *skb, > } > #endif > > +struct rec_lock { > + spinlock_t lock; > + int count; /* recursion count */ > +}; > +static DEFINE_PER_CPU(struct rec_lock, ip6_tables_lock); > + > /* Returns one of the generic firewall policies, like NF_ACCEPT. */ > unsigned int > ip6t_do_table(struct sk_buff *skb, > @@ -347,6 +353,7 @@ ip6t_do_table(struct sk_buff *skb, > struct xt_table_info *private; > struct xt_match_param mtpar; > struct xt_target_param tgpar; > + struct rec_lock *rl; > > /* Initialization */ > indev = in ? in->name : nulldevname; > @@ -367,7 +374,12 @@ ip6t_do_table(struct sk_buff *skb, > > rcu_read_lock_bh(); > private = rcu_dereference(table->private); > - table_base = rcu_dereference(private->entries[smp_processor_id()]); > + > + rl = &__get_cpu_var(ip_tables_lock); > + if (likely(rl->count++ == 0)) > + spin_lock(&rl->lock); > + > + table_base = private->entries[smp_processor_id()]; > > e = get_entry(table_base, private->hook_entry[hook]); > > @@ -467,6 +479,8 @@ ip6t_do_table(struct sk_buff *skb, > ((struct ip6t_entry *)table_base)->comefrom = NETFILTER_LINK_POISON; > #endif > rcu_read_unlock_bh(); > + if (likely(--rl->count == 0)) > + spin_unlock(&rl->lock); > > #ifdef DEBUG_ALLOW_ALL > return NF_ACCEPT; > @@ -931,73 +945,25 @@ get_counters(const struct xt_table_info *t, > curcpu = raw_smp_processor_id(); > > i = 0; > + spin_lock_bh(&per_cpu(ip6_tables_lock, curcpu).lock); > IP6T_ENTRY_ITERATE(t->entries[curcpu], > t->size, > set_entry_to_counter, > counters, > &i); > + spin_unlock_bh(&per_cpu(ip6_tables_lock, curcpu).lock); > > for_each_possible_cpu(cpu) { > if (cpu == curcpu) > continue; > i = 0; > + spin_lock_bh(&per_cpu(ip6_tables_lock, cpu).lock); > IP6T_ENTRY_ITERATE(t->entries[cpu], > t->size, > add_entry_to_counter, > counters, > &i); > - } > -} > - > -/* We're lazy, and add to the first CPU; overflow works its fey magic > - * and everything is OK. */ > -static int > -add_counter_to_entry(struct ip6t_entry *e, > - const struct xt_counters addme[], > - unsigned int *i) > -{ > - ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt); > - > - (*i)++; > - return 0; > -} > - > -/* Take values from counters and add them back onto the current cpu */ > -static void put_counters(struct xt_table_info *t, > - const struct xt_counters counters[]) > -{ > - unsigned int i, cpu; > - > - local_bh_disable(); > - cpu = smp_processor_id(); > - i = 0; > - IP6T_ENTRY_ITERATE(t->entries[cpu], > - t->size, > - add_counter_to_entry, > - counters, > - &i); > - local_bh_enable(); > -} > - > -static inline int > -zero_entry_counter(struct ip6t_entry *e, void *arg) > -{ > - e->counters.bcnt = 0; > - e->counters.pcnt = 0; > - return 0; > -} > - > -static void > -clone_counters(struct xt_table_info *newinfo, const struct xt_table_info *info) > -{ > - unsigned int cpu; > - const void *loc_cpu_entry = info->entries[raw_smp_processor_id()]; > - > - memcpy(newinfo, info, offsetof(struct xt_table_info, entries)); > - for_each_possible_cpu(cpu) { > - memcpy(newinfo->entries[cpu], loc_cpu_entry, info->size); > - IP6T_ENTRY_ITERATE(newinfo->entries[cpu], newinfo->size, > - zero_entry_counter, NULL); > + spin_unlock_bh(&per_cpu(ip6_tables_lock, cpu).lock); > } > } > > @@ -1006,7 +972,6 @@ static struct xt_counters *alloc_counters(struct xt_table *table) > unsigned int countersize; > struct xt_counters *counters; > struct xt_table_info *private = table->private; > - struct xt_table_info *info; > > /* We need atomic snapshot of counters: rest doesn't change > (other than comefrom, which userspace doesn't care > @@ -1015,30 +980,11 @@ static struct xt_counters *alloc_counters(struct xt_table *table) > counters = vmalloc_node(countersize, numa_node_id()); > > if (counters == NULL) > - goto nomem; > - > - info = xt_alloc_table_info(private->size); > - if (!info) > - goto free_counters; > - > - clone_counters(info, private); > - > - mutex_lock(&table->lock); > - xt_table_entry_swap_rcu(private, info); > - synchronize_net(); /* Wait until smoke has cleared */ > + return ERR_PTR(-ENOMEM); > > - get_counters(info, counters); > - put_counters(private, counters); > - mutex_unlock(&table->lock); > - > - xt_free_table_info(info); > + get_counters(private, counters); > > return counters; > - > - free_counters: > - vfree(counters); > - nomem: > - return ERR_PTR(-ENOMEM); > } > > static int > @@ -1405,6 +1351,19 @@ do_replace(struct net *net, void __user *user, unsigned int len) > return ret; > } > > +/* We're lazy, and add to the first CPU; overflow works its fey magic > + * and everything is OK. */ > +static int > +add_counter_to_entry(struct ip6t_entry *e, > + const struct xt_counters addme[], > + unsigned int *i) > +{ > + ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt); > + > + (*i)++; > + return 0; > +} > + > static int > do_add_counters(struct net *net, void __user *user, unsigned int len, > int compat) > @@ -1465,25 +1424,26 @@ do_add_counters(struct net *net, void __user *user, unsigned int len, > goto free; > } > > - mutex_lock(&t->lock); > private = t->private; > if (private->number != num_counters) { > ret = -EINVAL; > goto unlock_up_free; > } > > - preempt_disable(); > - i = 0; > + local_bh_disable(); > /* Choose the copy that is on our node */ > - loc_cpu_entry = private->entries[raw_smp_processor_id()]; > + spin_lock(&__get_cpu_var(ip6_tables_lock).lock); > + loc_cpu_entry = private->entries[smp_processor_id()]; > + i = 0; > IP6T_ENTRY_ITERATE(loc_cpu_entry, > private->size, > add_counter_to_entry, > paddc, > &i); > - preempt_enable(); > + spin_unlock(&__get_cpu_var(ip6_tables_lock).lock); > + local_bh_enable(); > + > unlock_up_free: > - mutex_unlock(&t->lock); > xt_table_unlock(t); > module_put(t->me); > free: > @@ -2298,7 +2258,10 @@ static struct pernet_operations ip6_tables_net_ops = { > > static int __init ip6_tables_init(void) > { > - int ret; > + int cpu, ret; > + > + for_each_possible_cpu(cpu) > + spin_lock_init(&per_cpu(ip6_tables_lock, cpu).lock); > > ret = register_pernet_subsys(&ip6_tables_net_ops); > if (ret < 0) > diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c > index 509a956..adc1b11 100644 > --- a/net/netfilter/x_tables.c > +++ b/net/netfilter/x_tables.c > @@ -625,20 +625,6 @@ void xt_free_table_info(struct xt_table_info *info) > } > EXPORT_SYMBOL(xt_free_table_info); > > -void xt_table_entry_swap_rcu(struct xt_table_info *oldinfo, > - struct xt_table_info *newinfo) > -{ > - unsigned int cpu; > - > - for_each_possible_cpu(cpu) { > - void *p = oldinfo->entries[cpu]; > - rcu_assign_pointer(oldinfo->entries[cpu], newinfo->entries[cpu]); > - newinfo->entries[cpu] = p; > - } > - > -} > -EXPORT_SYMBOL_GPL(xt_table_entry_swap_rcu); > - > /* Find table by name, grabs mutex & ref. Returns ERR_PTR() on error. */ > struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af, > const char *name) > @@ -682,26 +668,21 @@ xt_replace_table(struct xt_table *table, > struct xt_table_info *newinfo, > int *error) > { > - struct xt_table_info *oldinfo, *private; > + struct xt_table_info *private; > > /* Do the substitution. */ > - mutex_lock(&table->lock); > private = table->private; > /* Check inside lock: is the old number correct? */ > if (num_counters != private->number) { > duprintf("num_counters != table->private->number (%u/%u)\n", > num_counters, private->number); > - mutex_unlock(&table->lock); > *error = -EAGAIN; > return NULL; > } > - oldinfo = private; > rcu_assign_pointer(table->private, newinfo); > - newinfo->initial_entries = oldinfo->initial_entries; > - mutex_unlock(&table->lock); > + newinfo->initial_entries = private->initial_entries; > > - synchronize_net(); > - return oldinfo; > + return private; > } > EXPORT_SYMBOL_GPL(xt_replace_table); > > @@ -734,7 +715,6 @@ struct xt_table *xt_register_table(struct net *net, struct xt_table *table, > > /* Simplifies replace_table code. */ > table->private = bootstrap; > - mutex_init(&table->lock); > > if (!xt_replace_table(table, 0, newinfo, &ret)) > goto unlock; > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/