mac80211: fix skb buffering issue (and fixes to that)

mac80211: fix skb buffering issue (and fixes to that)

This is a backport of the mainline patches

 cf0277e714a0db302a8f80e1b85fd61c32cf00b3
 045cfb71a3901005bf6dcedae98cecb3360a0bfc
 b49bb574e44226b332c28439999d196ddec2f643

Here is the description of the first of
those patches (the other two just fixed
bugs added by that patch):

Since I removed the master netdev, we've been
keeping internal queues only, and even before
that we never told the networking stack above
the virtual interfaces about congestion. This
means that packets are queued in mac80211 and
the upper layers never know, possibly leading
to memory exhaustion and other problems.

This patch makes all interfaces multiqueue and
uses ndo_select_queue to put the packets into
queues per AC. Additionally, when the driver
stops a queue, we now stop all corresponding
queues for the virtual interfaces as well.

The injection case will use VO by default for
non-data frames, and BE for data frames, but
downgrade any data frames according to ACM. It
needs to be fleshed out in the future to allow
chosing the queue/AC in radiotap.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>