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: Florian Westphal <fw@strlen.de>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 3 deletions

diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 927fe58caf46..1211613c6c34 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -529,9 +529,7 @@ found:
             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: