From: Alistair Popple <redacted>
Date: Thu, 24 Oct 2013 14:36:20 +1100

This patch fixes a bug which would trigger the BUG_ON() at
net/core/dev.c:4156. It was found that this was due to napi_complete
being called even when the corresponding call to napi_reschedule had
failed.

This patch ensures that we only contine processing rotting packets in
the current mal_poll call if we are not already on the polling list.
It also adds locking calls to protect the read-write-modify of the
MAL_CFG DCR.

Signed-off-by: Alistair Popple <redacted>

The mistaken napi_complete() call and the locking change are two different
bugs, fix them in two different patches.