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Commit 3ef0eb0d authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by David S. Miller
Browse files

net: frag, move LRU list maintenance outside of rwlock 



Updating the fragmentation queues LRU (Least-Recently-Used) list,
required taking the hash writer lock.  However, the LRU list isn't
tied to the hash at all, so we can use a separate lock for it.

Original-idea-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6d7b857d

include/net/inet_frag.h

+22 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
struct netns_frags {

	int			nqueues;

	struct list_head	lru_list;

	spinlock_t		lru_lock;



	/* The percpu_counter "mem" need to be cacheline aligned.

	 *  mem.count must not share cacheline with other writers
@@ -116,4 +117,25 @@ static inline int sum_frag_mem_limit(struct netns_frags *nf) 
	return percpu_counter_sum_positive(&nf->mem);

}



static inline void inet_frag_lru_move(struct inet_frag_queue *q)

{

	spin_lock(&q->net->lru_lock);

	list_move_tail(&q->lru_list, &q->net->lru_list);

	spin_unlock(&q->net->lru_lock);

}



static inline void inet_frag_lru_del(struct inet_frag_queue *q)

{

	spin_lock(&q->net->lru_lock);

	list_del(&q->lru_list);

	spin_unlock(&q->net->lru_lock);

}



static inline void inet_frag_lru_add(struct netns_frags *nf,

				     struct inet_frag_queue *q)

{

	spin_lock(&nf->lru_lock);

	list_add_tail(&q->lru_list, &nf->lru_list);

	spin_unlock(&nf->lru_lock);

}

#endif

net/ipv4/inet_fragment.c

+7 −5
Original line number Diff line number Diff line
@@ -75,6 +75,7 @@ void inet_frags_init_net(struct netns_frags *nf) 
	nf->nqueues = 0;

	init_frag_mem_limit(nf);

	INIT_LIST_HEAD(&nf->lru_list);

	spin_lock_init(&nf->lru_lock);

}

EXPORT_SYMBOL(inet_frags_init_net);
@@ -100,9 +101,9 @@ static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f) 
{

	write_lock(&f->lock);

	hlist_del(&fq->list);

	list_del(&fq->lru_list);

	fq->net->nqueues--;

	write_unlock(&f->lock);

	inet_frag_lru_del(fq);

}



void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)
@@ -170,16 +171,17 @@ int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force) 


	work = frag_mem_limit(nf) - nf->low_thresh;

	while (work > 0) {

		read_lock(&f->lock);

		spin_lock(&nf->lru_lock);



		if (list_empty(&nf->lru_list)) {

			read_unlock(&f->lock);

			spin_unlock(&nf->lru_lock);

			break;

		}



		q = list_first_entry(&nf->lru_list,

				struct inet_frag_queue, lru_list);

		atomic_inc(&q->refcnt);

		read_unlock(&f->lock);

		spin_unlock(&nf->lru_lock);



		spin_lock(&q->lock);

		if (!(q->last_in & INET_FRAG_COMPLETE))
@@ -233,9 +235,9 @@ 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, &nf->lru_list);

	nf->nqueues++;

	write_unlock(&f->lock);

	inet_frag_lru_add(nf, qp);

	return qp;

}

net/ipv4/ip_fragment.c

+1 −3
Original line number Diff line number Diff line
@@ -529,9 +529,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) 
	    qp->q.meat == qp->q.len)

		return ip_frag_reasm(qp, prev, dev);



	write_lock(&ip4_frags.lock);

	list_move_tail(&qp->q.lru_list, &qp->q.net->lru_list);

	write_unlock(&ip4_frags.lock);

	inet_frag_lru_move(&qp->q);

	return -EINPROGRESS;



err:

net/ipv6/netfilter/nf_conntrack_reasm.c

+2 −3
Original line number Diff line number Diff line
@@ -328,9 +328,8 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, 
		fq->nhoffset = nhoff;

		fq->q.last_in |= INET_FRAG_FIRST_IN;

	}

	write_lock(&nf_frags.lock);

	list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);

	write_unlock(&nf_frags.lock);



	inet_frag_lru_move(&fq->q);

	return 0;



discard_fq:

net/ipv6/reassembly.c

+1 −3
Original line number Diff line number Diff line
@@ -341,9 +341,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 
	    fq->q.meat == fq->q.len)

		return ip6_frag_reasm(fq, prev, dev);



	write_lock(&ip6_frags.lock);

	list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);

	write_unlock(&ip6_frags.lock);

	inet_frag_lru_move(&fq->q);

	return -1;



discard_fq: