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ipv6: per netns fib6 walkers
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The IPv6 FIB data structures are separated per network namespace but
there is still only one global walkers list and one global walker list
lock. This means changes in one namespace unnecessarily interfere with
walkers in other namespaces.

Replace the global list with per-netns lists (and give each its own
lock).

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Michal Kubeček authored and David S. Miller committed Mar 8, 2016
1 parent 3570df9 commit 9a03cd8
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Showing 2 changed files with 38 additions and 32 deletions.
2 changes: 2 additions & 0 deletions include/net/netns/ipv6.h
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,9 @@ struct netns_ipv6 {
struct timer_list ip6_fib_timer;
struct hlist_head *fib_table_hash;
struct fib6_table *fib6_main_tbl;
struct list_head fib6_walkers;
struct dst_ops ip6_dst_ops;
rwlock_t fib6_walker_lock;
unsigned int ip6_rt_gc_expire;
unsigned long ip6_rt_last_gc;
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
Expand Down
68 changes: 36 additions & 32 deletions net/ipv6/ip6_fib.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -55,8 +55,6 @@ struct fib6_cleaner {
void *arg;
};

static DEFINE_RWLOCK(fib6_walker_lock);

#ifdef CONFIG_IPV6_SUBTREES
#define FWS_INIT FWS_S
#else
Expand All @@ -66,7 +64,7 @@ static DEFINE_RWLOCK(fib6_walker_lock);
static void fib6_prune_clones(struct net *net, struct fib6_node *fn);
static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
static int fib6_walk(struct fib6_walker *w);
static int fib6_walk(struct net *net, struct fib6_walker *w);
static int fib6_walk_continue(struct fib6_walker *w);

/*
Expand All @@ -78,21 +76,21 @@ static int fib6_walk_continue(struct fib6_walker *w);

static void fib6_gc_timer_cb(unsigned long arg);

static LIST_HEAD(fib6_walkers);
#define FOR_WALKERS(w) list_for_each_entry(w, &fib6_walkers, lh)
#define FOR_WALKERS(net, w) \
list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh)

static void fib6_walker_link(struct fib6_walker *w)
static void fib6_walker_link(struct net *net, struct fib6_walker *w)
{
write_lock_bh(&fib6_walker_lock);
list_add(&w->lh, &fib6_walkers);
write_unlock_bh(&fib6_walker_lock);
write_lock_bh(&net->ipv6.fib6_walker_lock);
list_add(&w->lh, &net->ipv6.fib6_walkers);
write_unlock_bh(&net->ipv6.fib6_walker_lock);
}

static void fib6_walker_unlink(struct fib6_walker *w)
static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
{
write_lock_bh(&fib6_walker_lock);
write_lock_bh(&net->ipv6.fib6_walker_lock);
list_del(&w->lh);
write_unlock_bh(&fib6_walker_lock);
write_unlock_bh(&net->ipv6.fib6_walker_lock);
}

static int fib6_new_sernum(struct net *net)
Expand Down Expand Up @@ -325,12 +323,13 @@ static int fib6_dump_node(struct fib6_walker *w)

static void fib6_dump_end(struct netlink_callback *cb)
{
struct net *net = sock_net(cb->skb->sk);
struct fib6_walker *w = (void *)cb->args[2];

if (w) {
if (cb->args[4]) {
cb->args[4] = 0;
fib6_walker_unlink(w);
fib6_walker_unlink(net, w);
}
cb->args[2] = 0;
kfree(w);
Expand All @@ -348,6 +347,7 @@ static int fib6_dump_done(struct netlink_callback *cb)
static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
struct fib6_walker *w;
int res;

Expand All @@ -359,7 +359,7 @@ static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
w->skip = 0;

read_lock_bh(&table->tb6_lock);
res = fib6_walk(w);
res = fib6_walk(net, w);
read_unlock_bh(&table->tb6_lock);
if (res > 0) {
cb->args[4] = 1;
Expand All @@ -379,7 +379,7 @@ static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
res = fib6_walk_continue(w);
read_unlock_bh(&table->tb6_lock);
if (res <= 0) {
fib6_walker_unlink(w);
fib6_walker_unlink(net, w);
cb->args[4] = 0;
}
}
Expand Down Expand Up @@ -1340,8 +1340,8 @@ static struct fib6_node *fib6_repair_tree(struct net *net,
}
#endif

read_lock(&fib6_walker_lock);
FOR_WALKERS(w) {
read_lock(&net->ipv6.fib6_walker_lock);
FOR_WALKERS(net, w) {
if (!child) {
if (w->root == fn) {
w->root = w->node = NULL;
Expand All @@ -1368,7 +1368,7 @@ static struct fib6_node *fib6_repair_tree(struct net *net,
}
}
}
read_unlock(&fib6_walker_lock);
read_unlock(&net->ipv6.fib6_walker_lock);

node_free(fn);
if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
Expand Down Expand Up @@ -1411,16 +1411,16 @@ static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
}

/* Adjust walkers */
read_lock(&fib6_walker_lock);
FOR_WALKERS(w) {
read_lock(&net->ipv6.fib6_walker_lock);
FOR_WALKERS(net, w) {
if (w->state == FWS_C && w->leaf == rt) {
RT6_TRACE("walker %p adjusted by delroute\n", w);
w->leaf = rt->dst.rt6_next;
if (!w->leaf)
w->state = FWS_U;
}
}
read_unlock(&fib6_walker_lock);
read_unlock(&net->ipv6.fib6_walker_lock);

rt->dst.rt6_next = NULL;

Expand Down Expand Up @@ -1588,17 +1588,17 @@ static int fib6_walk_continue(struct fib6_walker *w)
}
}

static int fib6_walk(struct fib6_walker *w)
static int fib6_walk(struct net *net, struct fib6_walker *w)
{
int res;

w->state = FWS_INIT;
w->node = w->root;

fib6_walker_link(w);
fib6_walker_link(net, w);
res = fib6_walk_continue(w);
if (res <= 0)
fib6_walker_unlink(w);
fib6_walker_unlink(net, w);
return res;
}

Expand Down Expand Up @@ -1668,7 +1668,7 @@ static void fib6_clean_tree(struct net *net, struct fib6_node *root,
c.arg = arg;
c.net = net;

fib6_walk(&c.w);
fib6_walk(net, &c.w);
}

static void __fib6_clean_all(struct net *net,
Expand Down Expand Up @@ -1816,6 +1816,8 @@ static int __net_init fib6_net_init(struct net *net)
{
size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;

rwlock_init(&net->ipv6.fib6_walker_lock);
INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);

net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
Expand Down Expand Up @@ -1976,7 +1978,8 @@ static int ipv6_route_yield(struct fib6_walker *w)
return 0;
}

static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter)
static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
struct net *net)
{
memset(&iter->w, 0, sizeof(iter->w));
iter->w.func = ipv6_route_yield;
Expand All @@ -1986,7 +1989,7 @@ static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter)
iter->w.args = iter;
iter->sernum = iter->w.root->fn_sernum;
INIT_LIST_HEAD(&iter->w.lh);
fib6_walker_link(&iter->w);
fib6_walker_link(net, &iter->w);
}

static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
Expand Down Expand Up @@ -2047,16 +2050,16 @@ static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
++*pos;
return iter->w.leaf;
} else if (r < 0) {
fib6_walker_unlink(&iter->w);
fib6_walker_unlink(net, &iter->w);
return NULL;
}
fib6_walker_unlink(&iter->w);
fib6_walker_unlink(net, &iter->w);

iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
if (!iter->tbl)
return NULL;

ipv6_route_seq_setup_walk(iter);
ipv6_route_seq_setup_walk(iter, net);
goto iter_table;
}

Expand All @@ -2071,7 +2074,7 @@ static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
iter->skip = *pos;

if (iter->tbl) {
ipv6_route_seq_setup_walk(iter);
ipv6_route_seq_setup_walk(iter, net);
return ipv6_route_seq_next(seq, NULL, pos);
} else {
return NULL;
Expand All @@ -2087,10 +2090,11 @@ static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
__releases(RCU_BH)
{
struct net *net = seq_file_net(seq);
struct ipv6_route_iter *iter = seq->private;

if (ipv6_route_iter_active(iter))
fib6_walker_unlink(&iter->w);
fib6_walker_unlink(net, &iter->w);

rcu_read_unlock_bh();
}
Expand Down

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