tree d90c737e057e2f7ec97a9d12218c646550adc707
parent b1c6a3a46b8b49ea6344264c1a24f1e51196761e
author Michal Kubeček <mkubecek@suse.cz> 1464364432 +0200
committer David S. Miller <davem@davemloft.net> 1465181802 -0400

net: disable fragment reassembly if high_thresh is zero

Before commit 6d7b857d541e ("net: use lib/percpu_counter API for
fragmentation mem accounting"), setting the reassembly high threshold
to 0 prevented fragment reassembly as first fragment would be always
evicted before second could be added to the queue. While inefficient,
some users apparently relied on this method.

Since the commit mentioned above, a percpu counter is used for
reassembly memory accounting and high batch size avoids taking slow path
in most common scenarios. As a result, a whole full sized packet can be
reassembled without the percpu counter's main counter changing its value
so that even with high_thresh set to 0, fragmented packets can be still
reassembled and processed.

Add explicit check preventing reassembly if high threshold is zero.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>