mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-14 17:46:54 +07:00
0d5b9311ba
Multiple cpus might attempt to insert a new fragment in rhashtable,
if for example RPS is buggy, as reported by 배석진 in
https://patchwork.ozlabs.org/patch/994601/
We use rhashtable_lookup_get_insert_key() instead of
rhashtable_insert_fast() to let cpus losing the race
free their own inet_frag_queue and use the one that
was inserted by another cpu.
Fixes: 648700f76b
("inet: frags: use rhashtables for reassembly units")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: 배석진 <soukjin.bae@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
227 lines
5.7 KiB
C
227 lines
5.7 KiB
C
/*
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* inet fragments management
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Pavel Emelyanov <xemul@openvz.org>
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* Started as consolidation of ipv4/ip_fragment.c,
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* ipv6/reassembly. and ipv6 nf conntrack reassembly
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*/
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/module.h>
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#include <linux/timer.h>
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#include <linux/mm.h>
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#include <linux/random.h>
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#include <linux/skbuff.h>
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#include <linux/rtnetlink.h>
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#include <linux/slab.h>
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#include <linux/rhashtable.h>
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#include <net/sock.h>
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#include <net/inet_frag.h>
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#include <net/inet_ecn.h>
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/* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
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* Value : 0xff if frame should be dropped.
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* 0 or INET_ECN_CE value, to be ORed in to final iph->tos field
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*/
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const u8 ip_frag_ecn_table[16] = {
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/* at least one fragment had CE, and others ECT_0 or ECT_1 */
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[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = INET_ECN_CE,
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[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = INET_ECN_CE,
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[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = INET_ECN_CE,
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/* invalid combinations : drop frame */
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
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};
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EXPORT_SYMBOL(ip_frag_ecn_table);
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int inet_frags_init(struct inet_frags *f)
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{
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f->frags_cachep = kmem_cache_create(f->frags_cache_name, f->qsize, 0, 0,
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NULL);
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if (!f->frags_cachep)
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return -ENOMEM;
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return 0;
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}
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EXPORT_SYMBOL(inet_frags_init);
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void inet_frags_fini(struct inet_frags *f)
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{
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/* We must wait that all inet_frag_destroy_rcu() have completed. */
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rcu_barrier();
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kmem_cache_destroy(f->frags_cachep);
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f->frags_cachep = NULL;
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}
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EXPORT_SYMBOL(inet_frags_fini);
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static void inet_frags_free_cb(void *ptr, void *arg)
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{
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struct inet_frag_queue *fq = ptr;
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/* If we can not cancel the timer, it means this frag_queue
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* is already disappearing, we have nothing to do.
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* Otherwise, we own a refcount until the end of this function.
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*/
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if (!del_timer(&fq->timer))
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return;
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spin_lock_bh(&fq->lock);
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if (!(fq->flags & INET_FRAG_COMPLETE)) {
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fq->flags |= INET_FRAG_COMPLETE;
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refcount_dec(&fq->refcnt);
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}
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spin_unlock_bh(&fq->lock);
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inet_frag_put(fq);
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}
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void inet_frags_exit_net(struct netns_frags *nf)
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{
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nf->high_thresh = 0; /* prevent creation of new frags */
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rhashtable_free_and_destroy(&nf->rhashtable, inet_frags_free_cb, NULL);
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}
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EXPORT_SYMBOL(inet_frags_exit_net);
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void inet_frag_kill(struct inet_frag_queue *fq)
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{
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if (del_timer(&fq->timer))
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refcount_dec(&fq->refcnt);
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if (!(fq->flags & INET_FRAG_COMPLETE)) {
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struct netns_frags *nf = fq->net;
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fq->flags |= INET_FRAG_COMPLETE;
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rhashtable_remove_fast(&nf->rhashtable, &fq->node, nf->f->rhash_params);
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refcount_dec(&fq->refcnt);
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}
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}
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EXPORT_SYMBOL(inet_frag_kill);
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static void inet_frag_destroy_rcu(struct rcu_head *head)
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{
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struct inet_frag_queue *q = container_of(head, struct inet_frag_queue,
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rcu);
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struct inet_frags *f = q->net->f;
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if (f->destructor)
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f->destructor(q);
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kmem_cache_free(f->frags_cachep, q);
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}
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void inet_frag_destroy(struct inet_frag_queue *q)
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{
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struct sk_buff *fp;
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struct netns_frags *nf;
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unsigned int sum, sum_truesize = 0;
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struct inet_frags *f;
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WARN_ON(!(q->flags & INET_FRAG_COMPLETE));
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WARN_ON(del_timer(&q->timer) != 0);
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/* Release all fragment data. */
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fp = q->fragments;
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nf = q->net;
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f = nf->f;
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if (fp) {
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do {
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struct sk_buff *xp = fp->next;
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sum_truesize += fp->truesize;
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kfree_skb(fp);
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fp = xp;
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} while (fp);
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} else {
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sum_truesize = inet_frag_rbtree_purge(&q->rb_fragments);
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}
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sum = sum_truesize + f->qsize;
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call_rcu(&q->rcu, inet_frag_destroy_rcu);
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sub_frag_mem_limit(nf, sum);
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}
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EXPORT_SYMBOL(inet_frag_destroy);
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static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf,
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struct inet_frags *f,
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void *arg)
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{
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struct inet_frag_queue *q;
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q = kmem_cache_zalloc(f->frags_cachep, GFP_ATOMIC);
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if (!q)
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return NULL;
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q->net = nf;
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f->constructor(q, arg);
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add_frag_mem_limit(nf, f->qsize);
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timer_setup(&q->timer, f->frag_expire, 0);
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spin_lock_init(&q->lock);
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refcount_set(&q->refcnt, 3);
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return q;
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}
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static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf,
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void *arg,
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struct inet_frag_queue **prev)
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{
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struct inet_frags *f = nf->f;
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struct inet_frag_queue *q;
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q = inet_frag_alloc(nf, f, arg);
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if (!q) {
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*prev = ERR_PTR(-ENOMEM);
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return NULL;
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}
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mod_timer(&q->timer, jiffies + nf->timeout);
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*prev = rhashtable_lookup_get_insert_key(&nf->rhashtable, &q->key,
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&q->node, f->rhash_params);
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if (*prev) {
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q->flags |= INET_FRAG_COMPLETE;
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inet_frag_kill(q);
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inet_frag_destroy(q);
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return NULL;
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}
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return q;
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}
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/* TODO : call from rcu_read_lock() and no longer use refcount_inc_not_zero() */
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struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, void *key)
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{
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struct inet_frag_queue *fq = NULL, *prev;
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if (!nf->high_thresh || frag_mem_limit(nf) > nf->high_thresh)
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return NULL;
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rcu_read_lock();
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prev = rhashtable_lookup(&nf->rhashtable, key, nf->f->rhash_params);
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if (!prev)
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fq = inet_frag_create(nf, key, &prev);
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if (prev && !IS_ERR(prev)) {
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fq = prev;
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if (!refcount_inc_not_zero(&fq->refcnt))
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fq = NULL;
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}
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rcu_read_unlock();
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return fq;
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}
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EXPORT_SYMBOL(inet_frag_find);
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