diff options
author | Pablo Neira Ayuso <pablo@netfilter.org> | 2018-12-28 03:24:48 +0300 |
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committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2018-12-29 04:45:22 +0300 |
commit | c80f10bc973af2ace6b1414724eeff61eaa71837 (patch) | |
tree | db8a8a15e3a8c50b8a8a5626e200bf955a0eea89 /net/netfilter/nf_conncount.c | |
parent | 2f971a8f425545da52ca0e6bee81f5b1ea0ccc5f (diff) | |
download | linux-c80f10bc973af2ace6b1414724eeff61eaa71837.tar.xz |
netfilter: nf_conncount: speculative garbage collection on empty lists
Instead of removing a empty list node that might be reintroduced soon
thereafter, tentatively place the empty list node on the list passed to
tree_nodes_free(), then re-check if the list is empty again before erasing
it from the tree.
[ Florian: rebase on top of pending nf_conncount fixes ]
Fixes: 5c789e131cbb9 ("netfilter: nf_conncount: Add list lock and gc worker, and RCU for init tree search")
Reviewed-by: Shawn Bohrer <sbohrer@cloudflare.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter/nf_conncount.c')
-rw-r--r-- | net/netfilter/nf_conncount.c | 47 |
1 files changed, 15 insertions, 32 deletions
diff --git a/net/netfilter/nf_conncount.c b/net/netfilter/nf_conncount.c index d0fd195b19a8..f0b05dfebc6e 100644 --- a/net/netfilter/nf_conncount.c +++ b/net/netfilter/nf_conncount.c @@ -81,27 +81,20 @@ static int key_diff(const u32 *a, const u32 *b, unsigned int klen) return memcmp(a, b, klen * sizeof(u32)); } -static bool conn_free(struct nf_conncount_list *list, +static void conn_free(struct nf_conncount_list *list, struct nf_conncount_tuple *conn) { - bool free_entry = false; - lockdep_assert_held(&list->list_lock); list->count--; list_del(&conn->node); - if (list->count == 0) { - list->dead = true; - free_entry = true; - } kmem_cache_free(conncount_conn_cachep, conn); - return free_entry; } static const struct nf_conntrack_tuple_hash * find_or_evict(struct net *net, struct nf_conncount_list *list, - struct nf_conncount_tuple *conn, bool *free_entry) + struct nf_conncount_tuple *conn) { const struct nf_conntrack_tuple_hash *found; unsigned long a, b; @@ -121,7 +114,7 @@ find_or_evict(struct net *net, struct nf_conncount_list *list, */ age = a - b; if (conn->cpu == cpu || age >= 2) { - *free_entry = conn_free(list, conn); + conn_free(list, conn); return ERR_PTR(-ENOENT); } @@ -137,14 +130,13 @@ static int __nf_conncount_add(struct net *net, struct nf_conncount_tuple *conn, *conn_n; struct nf_conn *found_ct; unsigned int collect = 0; - bool free_entry = false; /* check the saved connections */ list_for_each_entry_safe(conn, conn_n, &list->head, node) { if (collect > CONNCOUNT_GC_MAX_NODES) break; - found = find_or_evict(net, list, conn, &free_entry); + found = find_or_evict(net, list, conn); if (IS_ERR(found)) { /* Not found, but might be about to be confirmed */ if (PTR_ERR(found) == -EAGAIN) { @@ -221,7 +213,6 @@ void nf_conncount_list_init(struct nf_conncount_list *list) spin_lock_init(&list->list_lock); INIT_LIST_HEAD(&list->head); list->count = 0; - list->dead = false; } EXPORT_SYMBOL_GPL(nf_conncount_list_init); @@ -233,7 +224,6 @@ bool nf_conncount_gc_list(struct net *net, struct nf_conncount_tuple *conn, *conn_n; struct nf_conn *found_ct; unsigned int collected = 0; - bool free_entry = false; bool ret = false; /* don't bother if other cpu is already doing GC */ @@ -241,15 +231,10 @@ bool nf_conncount_gc_list(struct net *net, return false; list_for_each_entry_safe(conn, conn_n, &list->head, node) { - found = find_or_evict(net, list, conn, &free_entry); + found = find_or_evict(net, list, conn); if (IS_ERR(found)) { - if (PTR_ERR(found) == -ENOENT) { - if (free_entry) { - spin_unlock(&list->list_lock); - return true; - } + if (PTR_ERR(found) == -ENOENT) collected++; - } continue; } @@ -260,10 +245,7 @@ bool nf_conncount_gc_list(struct net *net, * closed already -> ditch it */ nf_ct_put(found_ct); - if (conn_free(list, conn)) { - spin_unlock(&list->list_lock); - return true; - } + conn_free(list, conn); collected++; continue; } @@ -273,10 +255,8 @@ bool nf_conncount_gc_list(struct net *net, break; } - if (!list->count) { - list->dead = true; + if (!list->count) ret = true; - } spin_unlock(&list->list_lock); return ret; @@ -291,6 +271,7 @@ static void __tree_nodes_free(struct rcu_head *h) kmem_cache_free(conncount_rb_cachep, rbconn); } +/* caller must hold tree nf_conncount_locks[] lock */ static void tree_nodes_free(struct rb_root *root, struct nf_conncount_rb *gc_nodes[], unsigned int gc_count) @@ -300,8 +281,10 @@ static void tree_nodes_free(struct rb_root *root, while (gc_count) { rbconn = gc_nodes[--gc_count]; spin_lock(&rbconn->list.list_lock); - rb_erase(&rbconn->node, root); - call_rcu(&rbconn->rcu_head, __tree_nodes_free); + if (!rbconn->list.count) { + rb_erase(&rbconn->node, root); + call_rcu(&rbconn->rcu_head, __tree_nodes_free); + } spin_unlock(&rbconn->list.list_lock); } } @@ -318,7 +301,6 @@ insert_tree(struct net *net, struct rb_root *root, unsigned int hash, const u32 *key, - u8 keylen, const struct nf_conntrack_tuple *tuple, const struct nf_conntrack_zone *zone) { @@ -327,6 +309,7 @@ insert_tree(struct net *net, struct nf_conncount_rb *rbconn; struct nf_conncount_tuple *conn; unsigned int count = 0, gc_count = 0; + u8 keylen = data->keylen; bool do_gc = true; spin_lock_bh(&nf_conncount_locks[hash]); @@ -454,7 +437,7 @@ count_tree(struct net *net, if (!tuple) return 0; - return insert_tree(net, data, root, hash, key, keylen, tuple, zone); + return insert_tree(net, data, root, hash, key, tuple, zone); } static void tree_gc_worker(struct work_struct *work) |