[PATCH net 06/17] netfilter: ipset: mark the rcu locked areas properly

[Florian Westphal <fw@strlen.de>]

From: Jozsef Kadlecsik <kadlec@netfilter.org>

When we bump the uref counter, there's no need to keep
the rcu lock because the referred hash table can't
disappear. Also, from the same reason in mtype_gc we
need the rcu lock and not a spinlock.

Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/ipset/ip_set_hash_gen.h | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h
index dedf59b661dd..c9a071766243 100644
--- a/net/netfilter/ipset/ip_set_hash_gen.h
+++ b/net/netfilter/ipset/ip_set_hash_gen.h
@@ -569,9 +569,10 @@ mtype_gc(struct work_struct *work)
 	set = gc->set;
 	h = set->data;
 
-	spin_lock_bh(&set->lock);
-	t = ipset_dereference_set(h->table, set);
+	rcu_read_lock_bh();
+	t = rcu_dereference_bh(h->table);
 	atomic_inc(&t->uref);
+	rcu_read_unlock_bh();
 	numof_locks = ahash_numof_locks(t->htable_bits);
 	r = gc->region++;
 	if (r >= numof_locks) {
@@ -580,7 +581,6 @@ mtype_gc(struct work_struct *work)
 	next_run = (IPSET_GC_PERIOD(set->timeout) * HZ) / numof_locks;
 	if (next_run < HZ/10)
 		next_run = HZ/10;
-	spin_unlock_bh(&set->lock);
 
 	mtype_gc_do(set, h, t, r);
 
@@ -860,15 +860,13 @@ mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
 	key = HKEY(value, h->initval, t->htable_bits);
 	r = ahash_region(key);
 	atomic_inc(&t->uref);
+	rcu_read_unlock_bh();
 	elements = t->hregion[r].elements;
 	maxelem = t->maxelem;
 	if (elements >= maxelem) {
 		u32 e;
-		if (SET_WITH_TIMEOUT(set)) {
-			rcu_read_unlock_bh();
+		if (SET_WITH_TIMEOUT(set))
 			mtype_gc_do(set, h, t, r);
-			rcu_read_lock_bh();
-		}
 		maxelem = h->maxelem;
 		elements = 0;
 		for (e = 0; e < ahash_numof_locks(t->htable_bits); e++)
@@ -876,7 +874,6 @@ mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
 		if (elements >= maxelem && SET_WITH_FORCEADD(set))
 			forceadd = true;
 	}
-	rcu_read_unlock_bh();
 
 	spin_lock_bh(&t->hregion[r].lock);
 	n = rcu_dereference_bh(hbucket(t, key));
-- 
2.54.0