tree e91d28ce1852c8a7016065ee2184dd2531d56892
parent 1716a96101c49186bb0b8491922fd3e69030235f
author David Woodhouse <dwmw2@infradead.org> 1333879304 +0000
committer David S. Miller <davem@davemloft.net> 1334336807 -0400

ppp: Fix race condition with queue start/stop

Commit e675f0cc9a872fd152edc0c77acfed19bf28b81e ("ppp: Don't stop and
restart queue on every TX packet") introduced a race condition which
could leave the net queue stopped even when the channel is no longer
busy. By calling netif_stop_queue() from ppp_start_xmit(), based on the
return value from ppp_xmit_process() but *after* all the locks have been
dropped, we could potentially do so *after* the channel has actually
finished transmitting and attempted to re-wake the queue.

Fix this by moving the netif_stop_queue() into ppp_xmit_process() under
the xmit lock. I hadn't done this previously, because it gets called
from other places than ppp_start_xmit(). But I now think it's the better
option. The net queue *should* be stopped if the channel becomes
congested due to writes from pppd, anyway.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>