From 8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Sat, 21 Sep 2013 16:55:59 +0200 Subject: [PATCH] ipv6: avoid high order memory allocations for /proc/net/ipv6_route Dumping routes on a system with lots rt6_infos in the fibs causes up to 11-order allocations in seq_file (which fail). While we could switch there to vmalloc we could just implement the streaming interface for /proc/net/ipv6_route. This patch switches /proc/net/ipv6_route from single_open_net to seq_open_net. loff_t *pos tracks dst entries. Also kill never used struct rt6_proc_arg and now unused function fib6_clean_all_ro. Cc: Ben Greear Cc: Patrick McHardy Cc: YOSHIFUJI Hideaki Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- include/net/ip6_fib.h | 6 +- net/ipv6/ip6_fib.c | 191 +++++++++++++++++++++++++++++++++++++----- net/ipv6/route.c | 46 +--------- 3 files changed, 175 insertions(+), 68 deletions(-) diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index eab88f0e2088..6738f3409a6f 100644 --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -280,10 +280,6 @@ struct fib6_node *fib6_locate(struct fib6_node *root, const struct in6_addr *daddr, int dst_len, const struct in6_addr *saddr, int src_len); -void fib6_clean_all_ro(struct net *net, - int (*func)(struct rt6_info *, void *arg), - int prune, void *arg); - void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg), int prune, void *arg); @@ -299,6 +295,8 @@ void fib6_gc_cleanup(void); int fib6_init(void); +int ipv6_route_open(struct inode *inode, struct file *file); + #ifdef CONFIG_IPV6_MULTIPLE_TABLES int fib6_rules_init(void); void fib6_rules_cleanup(void); diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 5bec666aba61..05ffa54fcf21 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -1529,25 +1529,6 @@ static void fib6_clean_tree(struct net *net, struct fib6_node *root, fib6_walk(&c.w); } -void fib6_clean_all_ro(struct net *net, int (*func)(struct rt6_info *, void *arg), - int prune, void *arg) -{ - struct fib6_table *table; - struct hlist_head *head; - unsigned int h; - - rcu_read_lock(); - for (h = 0; h < FIB6_TABLE_HASHSZ; h++) { - head = &net->ipv6.fib_table_hash[h]; - hlist_for_each_entry_rcu(table, head, tb6_hlist) { - read_lock_bh(&table->tb6_lock); - fib6_clean_tree(net, &table->tb6_root, - func, prune, arg); - read_unlock_bh(&table->tb6_lock); - } - } - rcu_read_unlock(); -} void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg), int prune, void *arg) { @@ -1782,3 +1763,175 @@ void fib6_gc_cleanup(void) unregister_pernet_subsys(&fib6_net_ops); kmem_cache_destroy(fib6_node_kmem); } + +#ifdef CONFIG_PROC_FS + +struct ipv6_route_iter { + struct seq_net_private p; + struct fib6_walker_t w; + loff_t skip; + struct fib6_table *tbl; +}; + +static int ipv6_route_seq_show(struct seq_file *seq, void *v) +{ + struct rt6_info *rt = v; + struct ipv6_route_iter *iter = seq->private; + + seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen); + +#ifdef CONFIG_IPV6_SUBTREES + seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen); +#else + seq_puts(seq, "00000000000000000000000000000000 00 "); +#endif + if (rt->rt6i_flags & RTF_GATEWAY) + seq_printf(seq, "%pi6", &rt->rt6i_gateway); + else + seq_puts(seq, "00000000000000000000000000000000"); + + seq_printf(seq, " %08x %08x %08x %08x %8s\n", + rt->rt6i_metric, atomic_read(&rt->dst.__refcnt), + rt->dst.__use, rt->rt6i_flags, + rt->dst.dev ? rt->dst.dev->name : ""); + iter->w.leaf = NULL; + return 0; +} + +static int ipv6_route_yield(struct fib6_walker_t *w) +{ + struct ipv6_route_iter *iter = w->args; + + if (!iter->skip) + return 1; + + do { + iter->w.leaf = iter->w.leaf->dst.rt6_next; + iter->skip--; + if (!iter->skip && iter->w.leaf) + return 1; + } while (iter->w.leaf); + + return 0; +} + +static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter) +{ + memset(&iter->w, 0, sizeof(iter->w)); + iter->w.func = ipv6_route_yield; + iter->w.root = &iter->tbl->tb6_root; + iter->w.state = FWS_INIT; + iter->w.node = iter->w.root; + iter->w.args = iter; + INIT_LIST_HEAD(&iter->w.lh); + fib6_walker_link(&iter->w); +} + +static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl, + struct net *net) +{ + unsigned int h; + struct hlist_node *node; + + if (tbl) { + h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1; + node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist)); + } else { + h = 0; + node = NULL; + } + + while (!node && h < FIB6_TABLE_HASHSZ) { + node = rcu_dereference_bh( + hlist_first_rcu(&net->ipv6.fib_table_hash[h++])); + } + return hlist_entry_safe(node, struct fib6_table, tb6_hlist); +} + +static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + int r; + struct rt6_info *n; + struct net *net = seq_file_net(seq); + struct ipv6_route_iter *iter = seq->private; + + if (!v) + goto iter_table; + + n = ((struct rt6_info *)v)->dst.rt6_next; + if (n) { + ++*pos; + return n; + } + +iter_table: + read_lock(&iter->tbl->tb6_lock); + r = fib6_walk_continue(&iter->w); + read_unlock(&iter->tbl->tb6_lock); + if (r > 0) { + if (v) + ++*pos; + return iter->w.leaf; + } else if (r < 0) { + fib6_walker_unlink(&iter->w); + return NULL; + } + fib6_walker_unlink(&iter->w); + + iter->tbl = ipv6_route_seq_next_table(iter->tbl, net); + if (!iter->tbl) + return NULL; + + ipv6_route_seq_setup_walk(iter); + goto iter_table; +} + +static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos) + __acquires(RCU_BH) +{ + struct net *net = seq_file_net(seq); + struct ipv6_route_iter *iter = seq->private; + + rcu_read_lock_bh(); + iter->tbl = ipv6_route_seq_next_table(NULL, net); + iter->skip = *pos; + + if (iter->tbl) { + ipv6_route_seq_setup_walk(iter); + return ipv6_route_seq_next(seq, NULL, pos); + } else { + return NULL; + } +} + +static bool ipv6_route_iter_active(struct ipv6_route_iter *iter) +{ + struct fib6_walker_t *w = &iter->w; + return w->node && !(w->state == FWS_U && w->node == w->root); +} + +static void ipv6_route_seq_stop(struct seq_file *seq, void *v) + __releases(RCU_BH) +{ + struct ipv6_route_iter *iter = seq->private; + + if (ipv6_route_iter_active(iter)) + fib6_walker_unlink(&iter->w); + + rcu_read_unlock_bh(); +} + +static const struct seq_operations ipv6_route_seq_ops = { + .start = ipv6_route_seq_start, + .next = ipv6_route_seq_next, + .stop = ipv6_route_seq_stop, + .show = ipv6_route_seq_show +}; + +int ipv6_route_open(struct inode *inode, struct file *file) +{ + return seq_open_net(inode, file, &ipv6_route_seq_ops, + sizeof(struct ipv6_route_iter)); +} + +#endif /* CONFIG_PROC_FS */ diff --git a/net/ipv6/route.c b/net/ipv6/route.c index c979dd96d82a..aa901bb60cf2 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2800,56 +2800,12 @@ static int ip6_route_dev_notify(struct notifier_block *this, #ifdef CONFIG_PROC_FS -struct rt6_proc_arg -{ - char *buffer; - int offset; - int length; - int skip; - int len; -}; - -static int rt6_info_route(struct rt6_info *rt, void *p_arg) -{ - struct seq_file *m = p_arg; - - seq_printf(m, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen); - -#ifdef CONFIG_IPV6_SUBTREES - seq_printf(m, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen); -#else - seq_puts(m, "00000000000000000000000000000000 00 "); -#endif - if (rt->rt6i_flags & RTF_GATEWAY) { - seq_printf(m, "%pi6", &rt->rt6i_gateway); - } else { - seq_puts(m, "00000000000000000000000000000000"); - } - seq_printf(m, " %08x %08x %08x %08x %8s\n", - rt->rt6i_metric, atomic_read(&rt->dst.__refcnt), - rt->dst.__use, rt->rt6i_flags, - rt->dst.dev ? rt->dst.dev->name : ""); - return 0; -} - -static int ipv6_route_show(struct seq_file *m, void *v) -{ - struct net *net = (struct net *)m->private; - fib6_clean_all_ro(net, rt6_info_route, 0, m); - return 0; -} - -static int ipv6_route_open(struct inode *inode, struct file *file) -{ - return single_open_net(inode, file, ipv6_route_show); -} - static const struct file_operations ipv6_route_proc_fops = { .owner = THIS_MODULE, .open = ipv6_route_open, .read = seq_read, .llseek = seq_lseek, - .release = single_release_net, + .release = seq_release_net, }; static int rt6_stats_seq_show(struct seq_file *seq, void *v) -- 2.20.1