[NETNS][FRAGS]: Make the LRU list per namespace.

The inet_frags.lru_list is used for evicting only, so we have
to make it per-namespace, to evict only those fragments, who's
namespace exceeded its high threshold, but not the whole hash.
Besides, this helps to avoid long loops  in evictor.

The spinlock is not per-namespace because it protects the
hash table as well, which is global.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/inet_frag.h

@@ -4,6 +4,7 @@
 struct netns_frags {
 	int			nqueues;
 	atomic_t		mem;
+	struct list_head	lru_list;
 
 	/* sysctls */
 	int			timeout;
@@ -32,7 +33,6 @@ struct inet_frag_queue {
 #define INETFRAGS_HASHSZ		64
 
 struct inet_frags {
-	struct list_head	lru_list;
 	struct hlist_head	hash[INETFRAGS_HASHSZ];
 	rwlock_t		lock;
 	u32			rnd;

net/ipv4/inet_fragment.c

@@ -57,7 +57,6 @@ void inet_frags_init(struct inet_frags *f)
 	for (i = 0; i < INETFRAGS_HASHSZ; i++)
 		INIT_HLIST_HEAD(&f->hash[i]);
 
-	INIT_LIST_HEAD(&f->lru_list);
 	rwlock_init(&f->lock);
 
 	f->rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
@@ -74,6 +73,7 @@ void inet_frags_init_net(struct netns_frags *nf)
 {
 	nf->nqueues = 0;
 	atomic_set(&nf->mem, 0);
+	INIT_LIST_HEAD(&nf->lru_list);
 }
 EXPORT_SYMBOL(inet_frags_init_net);
 
@@ -156,12 +156,12 @@ int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f)
 	work = atomic_read(&nf->mem) - nf->low_thresh;
 	while (work > 0) {
 		read_lock(&f->lock);
-		if (list_empty(&f->lru_list)) {
+		if (list_empty(&nf->lru_list)) {
 			read_unlock(&f->lock);
 			break;
 		}
 
-		q = list_first_entry(&f->lru_list,
+		q = list_first_entry(&nf->lru_list,
 				struct inet_frag_queue, lru_list);
 		atomic_inc(&q->refcnt);
 		read_unlock(&f->lock);
@@ -211,7 +211,7 @@ static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf,
 
 	atomic_inc(&qp->refcnt);
 	hlist_add_head(&qp->list, &f->hash[hash]);
-	list_add_tail(&qp->lru_list, &f->lru_list);
+	list_add_tail(&qp->lru_list, &nf->lru_list);
 	nf->nqueues++;
 	write_unlock(&f->lock);
 	return qp;

net/ipv4/ip_fragment.c

@@ -441,7 +441,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 		return ip_frag_reasm(qp, prev, dev);
 
 	write_lock(&ip4_frags.lock);
-	list_move_tail(&qp->q.lru_list, &ip4_frags.lru_list);
+	list_move_tail(&qp->q.lru_list, &qp->q.net->lru_list);
 	write_unlock(&ip4_frags.lock);
 	return -EINPROGRESS;
 

net/ipv6/netfilter/nf_conntrack_reasm.c

@@ -385,7 +385,7 @@ static int nf_ct_frag6_queue(struct nf_ct_frag6_queue *fq, struct sk_buff *skb,
 		fq->q.last_in |= FIRST_IN;
 	}
 	write_lock(&nf_frags.lock);
-	list_move_tail(&fq->q.lru_list, &nf_frags.lru_list);
+	list_move_tail(&fq->q.lru_list, &nf_init_frags.lru_list);
 	write_unlock(&nf_frags.lock);
 	return 0;
 

net/ipv6/reassembly.c

@@ -424,7 +424,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 		return ip6_frag_reasm(fq, prev, dev);
 
 	write_lock(&ip6_frags.lock);
-	list_move_tail(&fq->q.lru_list, &ip6_frags.lru_list);
+	list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
 	write_unlock(&ip6_frags.lock);
 	return -1;