@@ -178,21 +178,22 @@ static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf,
}
static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf,
- void *arg)
+ void *arg,
+ struct inet_frag_queue **prev)
{
struct inet_frags *f = nf->f;
struct inet_frag_queue *q;
- int err;
q = inet_frag_alloc(nf, f, arg);
- if (!q)
+ if (!q) {
+ *prev = ERR_PTR(-ENOMEM);
return NULL;
-
+ }
mod_timer(&q->timer, jiffies + nf->timeout);
- err = rhashtable_insert_fast(&nf->rhashtable, &q->node,
- f->rhash_params);
- if (err < 0) {
+ *prev = rhashtable_lookup_get_insert_key(&nf->rhashtable, &q->key,
+ &q->node, f->rhash_params);
+ if (*prev) {
q->flags |= INET_FRAG_COMPLETE;
inet_frag_kill(q);
inet_frag_destroy(q);
@@ -204,22 +205,22 @@ static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf,
/* TODO : call from rcu_read_lock() and no longer use refcount_inc_not_zero() */
struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, void *key)
{
- struct inet_frag_queue *fq;
+ struct inet_frag_queue *fq = NULL, *prev;
if (!nf->high_thresh || frag_mem_limit(nf) > nf->high_thresh)
return NULL;
rcu_read_lock();
- fq = rhashtable_lookup(&nf->rhashtable, key, nf->f->rhash_params);
- if (fq) {
+ prev = rhashtable_lookup(&nf->rhashtable, key, nf->f->rhash_params);
+ if (!prev)
+ fq = inet_frag_create(nf, key, &prev);
+ if (prev && !IS_ERR(prev)) {
+ fq = prev;
if (!refcount_inc_not_zero(&fq->refcnt))
fq = NULL;
- rcu_read_unlock();
- return fq;
}
rcu_read_unlock();
-
- return inet_frag_create(nf, key);
+ return fq;
}
EXPORT_SYMBOL(inet_frag_find);
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: 648700f76b03 ("inet: frags: use rhashtables for reassembly units") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: 배석진 <soukjin.bae@samsung.com> --- net/ipv4/inet_fragment.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-)