tree a0bdd3b62f4f06c2fffc0d62cf7f6c58f286fdb5
parent 991fec091061b901e4fdcc8af4fd25d24a5a7bab
author Johannes Berg <johannes.berg@intel.com> 1366190800 +0200
committer Johannes Berg <johannes.berg@intel.com> 1366191639 +0200

mac80211: fix station entry leak/warning while suspending

Since Stanislaw's patches, when suspending while connected,
cfg80211 will disconnect. This causes the AP station to be
removed, which uses call_rcu() to clean up. Due to needing
process context, this queues a work struct on the mac80211
workqueue. This will warn and fail when already suspended,
which can happen if the rcu call doesn't happen quickly.

To fix this, replace the synchronize_net() which is really
just synchronize_rcu_expedited() with rcu_barrier(), which
unlike synchronize_rcu() waits until RCU callback have run
and thus avoids this issue.

In theory, this can even happen without Stanislaw's change
to disconnect on suspend since userspace might disconnect
just before suspending, though then it's unlikely that the
call_rcu() will be delayed long enough.

Cc: stable@vger.kernel.org [3.7+]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>