Commit 68399ac3 authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by David S. Miller
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net: frag, avoid several CPUs grabbing same frag queue during LRU evictor loop

The LRU list is protected by its own lock, since commit 3ef0eb0d


(net: frag, move LRU list maintenance outside of rwlock), and
no-longer by a read_lock.

This makes it possible, to remove the inet_frag_queue, which is about
to be "evicted", from the LRU list head.  This avoids the problem, of
several CPUs grabbing the same frag queue.

Note, cannot remove the inet_frag_lru_del() call in fq_unlink()
called by inet_frag_kill(), because inet_frag_kill() is also used in
other situations.  Thus, we use list_del_init() to allow this
double list_del to work.
Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 167bfa71
......@@ -204,6 +204,9 @@ int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force)
q = list_first_entry(&nf->lru_list,
struct inet_frag_queue, lru_list);
atomic_inc(&q->refcnt);
/* Remove q from list to avoid several CPUs grabbing it */
list_del_init(&q->lru_list);
spin_unlock(&nf->lru_lock);
spin_lock(&q->lock);
......
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