linux-toradex.git/net/mac80211/agg-tx.c, branch v3.14.9

mac80211: fix aggregation state with current drivers

2013-01-24T14:43:51+00:00

For drivers that don't actually flush their queues when
aggregation stop with the IEEE80211_AMPDU_TX_STOP_FLUSH
or IEEE80211_AMPDU_TX_STOP_FLUSH_CONT reasons is done,
like iwlwifi or iwlegacy, mac80211 can then transmit on
a TID that the driver still considers busy. This happens
in the following way:

 - IEEE80211_AMPDU_TX_STOP_FLUSH requested
 - driver marks TID as emptying
 - mac80211 removes tid_tx data, this can copy packets
   to the TX pending queues and also let new packets
   through to the driver
 - driver gets unexpected TX as it wasn't completely
   converted to the new API

In iwlwifi, this lead to the following warning:

WARNING: at drivers/net/wireless/iwlwifi/dvm/tx.c:442 iwlagn_tx_skb+0xc47/0xce0
Tx while agg.state = 4
Modules linked in: [...]
Pid: 0, comm: kworker/0:0 Tainted: G        W   3.1.0 #1
Call Trace:
 [] warn_slowpath_common+0x72/0xa0
 [] warn_slowpath_fmt+0x33/0x40
 [] iwlagn_tx_skb+0xc47/0xce0 [iwldvm]
 [] iwlagn_mac_tx+0x23/0x40 [iwldvm]
 [] __ieee80211_tx+0xf6/0x3c0 [mac80211]
 [] ieee80211_tx+0xd0/0x100 [mac80211]
 [] ieee80211_xmit+0x96/0xe0 [mac80211]
 [] ieee80211_subif_start_xmit+0x348/0xc80 [mac80211]
 [] dev_hard_start_xmit+0x337/0x6d0
 [] sch_direct_xmit+0xa9/0x210
 [] dev_queue_xmit+0x1b0/0x8e0

Fortunately, solving this problem is easy as the station
is being destroyed, so such transmit packets can only
happen due to races. Instead of trying to close the race
just let the race not reach the drivers by making two
changes:
 1) remove the explicit aggregation session teardown in
    the managed mode code, the same thing will be done
    when the station is removed, in __sta_info_destroy.
 2) When aggregation stop with AGG_STOP_DESTROY_STA is
    requested, leave the tid_tx data around as stopped.
    It will be cleared and freed in cleanup_single_sta
    later, but until then any racy packets will be put
    onto the tid_tx pending queue instead of transmitted
    which is fine since the station is being removed.

Signed-off-by: Johannes Berg

mac80211: improve aggregation debug messages

2013-01-18T20:55:15+00:00

A lot of the aggregation messages don't indicate the
station so they're hard to understand if there are
multiple sessions in progress. Make that easier by
adding the MAC address to most messages. Also add
the TID if it wasn't already there.

Signed-off-by: Johannes Berg

mac80211: split TX aggregation stop action

2013-01-03T12:01:42+00:00

When TX aggregation is stopped, there are a few
different cases:
 - connection with the peer was dropped
 - session stop was requested locally
 - session stop was requested by the peer
 - connection was dropped while a session is stopping

The behaviour in these cases should be different, if
the connection is dropped then the driver should drop
all frames, otherwise the frames may continue to be
transmitted, aggregated in the case of a locally
requested session stop or unaggregated in the case of
the peer requesting session stop.

Split these different cases so that the driver can
act accordingly; however, treat local and remote stop
the same way and ask the driver to not send frames as
aggregated packets any more.

In the case of connection drop, the stop callback the
driver is otherwise supposed to call is no longer
required.

Signed-off-by: Johannes Berg

mac80211: move ieee80211_remove_tid_tx function

2013-01-03T12:01:42+00:00

To call it from ___ieee80211_stop_tx_ba_session,
move the function and dependencies up.

Signed-off-by: Johannes Berg

mac80211: split out aggregation TX removal

2013-01-03T12:01:41+00:00

Create the function ieee80211_remove_tid_tx to call
it from ___ieee80211_stop_tx_ba_session later.

Signed-off-by: Johannes Berg

mac80211: split aggregation stop by reason

2013-01-03T12:01:41+00:00

The initiator/tx doesn't really identify why an
aggregation session is stopped, give a reason
for stopping that more clearly identifies what's
going on. This will help tell the driver clearly
what is expected of it.

Signed-off-by: Johannes Berg

mac80211: warn only once if ampdu_action isn't assigned

2012-12-07T08:12:50+00:00

New drivers that might not support ampdu_action yet while in
development cause a lot of warnings, use WARN_ON_ONCE instead.

Signed-off-by: T Krushna Chaitanya 
Signed-off-by: Johannes Berg

mac80211: introduce IEEE80211_NUM_TIDS and use it

2012-11-19T14:44:00+00:00

Introduce IEEE80211_NUM_TIDS in the generic 802.11
header file and use it in place of STA_TID_NUM and
NUM_RX_DATA_QUEUES which are both really the number
of TIDs.

Signed-off-by: Johannes Berg

mac80211: don't send delBA on addBA failure

2012-09-21T14:14:14+00:00

There's no reason to send a delBA when the
peer refused our addBA, so change that.

Signed-off-by: Johannes Berg

mac80211: request TX status for BlockAck Requests

2012-07-07T19:35:42+00:00

Because ieee80211_tx_status in status.c checks if
outgoing BlockAck requests have been acked, it is
necessary to tell the driver that tx feedback for
this sort of frame is important.

Otherwise, the stack will continue to send the same
BlockAck request over and over, which can cause
the receiver to flush or clean its reorder buffer
over and over.

Signed-off-by: Christian Lamparter 
Signed-off-by: Johannes Berg