Since mac80211 doesn't currently support TSIDs 8-15 which can
only be used after QoS TSPEC negotiation (and not even after
WMM negotiation), reject attempts to set up aggregation
sessions for them, which might confuse drivers. In mac80211
we do correctly handle that, but the TSIDs should never get
used anyway, and drivers might not be able to handle it.
Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211's software queues were designed to work
very closely with device tx queues. They are
required to make use of 802.11 packet aggregation
easily and efficiently.
Due to the way 802.11 aggregation is designed it
only makes sense to keep fair queuing as close to
hardware as possible to reduce induced latency and
inertia and provide the best flow responsiveness.
This change doesn't translate directly to
immediate and significant gains. End result
depends on driver's induced latency. Best results
can be achieved if driver keeps its own tx
queue/fifo fill level to a minimum.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Requires software tx queueing and fast-xmit support. For good
performance, drivers need frag_list support as well. This avoids the
need for copying data of aggregated frames. Running without it is only
supported for debugging purposes.
To avoid performance and packet size issues, the rate control module or
driver needs to limit the maximum A-MSDU size by setting
max_rc_amsdu_len in struct ieee80211_sta.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
[fix locking issue]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Currently mac80211 does not inform the driver of the session
block ack timeout when starting a rx aggregation session.
Drivers that manage the reorder buffer need to know this
parameter.
Seeing that there are now too many arguments for the
drv_ampdu_action() function, wrap them inside a structure.
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Advertising reordering window in ADDBA less than 64 can crash some APs,
an example is LinkSys WRT120N (with FW v1.0.07 build 002 Jun 18 2012).
On the other hand, a driver may need to limit Tx A-MPDU size for its own
reasons, like specific HW limitations.
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Advertise the capability to send A-MSDU within A-MPDU
in the AddBA request sent by mac80211. Let the driver
know about the peer's capabilities.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
As we're running out of hardware capability flags pretty quickly,
convert them to use the regular test_bit() style unsigned long
bitmaps.
This introduces a number of helper functions/macros to set and to
test the bits, along with new debugfs code.
The occurrences of an explicit __clear_bit() are intentional, the
drivers were never supposed to change their supported bits on the
fly. We should investigate changing this to be a per-frame flag.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This allows drivers to request per-vif and per-sta-tid queues from which
they can pull frames. This makes it easier to keep the hardware queues
short, and to improve fairness between clients and vifs.
The task of scheduling packet transmission is left up to the driver -
queueing is controlled by mac80211. Drivers can only dequeue packets by
calling ieee80211_tx_dequeue. This makes it possible to add active queue
management later without changing drivers using this code.
This can also be used as a starting point to implement A-MSDU
aggregation in a way that does not add artificially induced latency.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
[resolved minor context conflict, minor changes, endian annotations]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
If a peer or some local agent (rate control, ...) decides to start
an aggregation session but doesn't support HT (which also implies
QoS), reject it.
This is mostly a corner case as such peers normally won't try to
use block-ack sessions and rate control wouldn't start them, but
technically QoS stations could request it according to the spec.
However, since drivers don't really support such non-HT sessions
it's better to reject them.
Also, while at it, move the tracing for TX sessions earlier so it
captures the error cases as well.
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The rate control locking caused a potential deadlock here due to the
locks being acquired in different orders, so that change cannot yet
be applied. However, there's no fundamental reason for this code to
hold the sta->lock while transmitting frames.
Clearly it's better not to hold the lock for longer periods of time,
which can happen here since we call all the way down to the driver.
Change the code a bit to not hold it while doing that.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
In TDLS (e.g., TDLS off-channel) there is a requirement for
some drivers to supply an unused TID between the AP and the
device to the FW, to allow sending PTI requests and to allow
the FW to aggregate on a specific TID for better throughput.
To ensure that the allocated TID is indeed unused, this patch
introduces an API for blocking the driver from TXing on that
TID.
Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Use the currently existing APIs between mac80211 and the low
level driver to implement WMM admission control.
The low level driver needs to report the media time used by
each transmitted packet in ieee80211_tx_status. Based on that
information, mac80211 will modify the QoS parameters of the
admission controlled Access Category when the limit is
reached. Once the original QoS parameters can be restored,
mac80211 will do so.
One issue with this approach is that management frames will
also erroneously be downgraded, but the upside is that the
implementation is simple. In the future, it can be extended
to driver- or device-based implementations that are better.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Sometimes different vifs may be stopping the queues for the same
reason (e.g. when several interfaces are performing a channel switch).
Instead of using a bitmask for the reasons, use an integer that holds
a refcount instead. In order to keep it backwards compatible,
introduce a boolean in some functions that tell us whether the queue
stopping should be refcounted or not. For now, use not refcounted for
all calls to keep it functionally the same as before.
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
ATM, {ADD,DEL}BA and BAR frames are sent on the AC matching the TID of
the BA parameters. In the discussion [1] about this patch, Johannes
recalled that it fixed some races with the DELBA and indeed this
behavior was introduced in [2].
While [2] is right for the BARs, the part queueing the {ADD,DEL}BAs on
their BA params TID AC violates the spec and is more a workaround for
some drivers. Helmut expressed some concerns wrt such drivers, in
particular DELBAs in rt2x00.
ATM, DELBAs are sent after a driver has called (hence "purposely")
ieee80211_start_tx_ba_cb_irqsafe and Johannes and Emmanuel gave some
details wrt intentions behind the split of the IEEE80211_AMPDU_TX_STOP_*
given to the driver ampdu_action supposed to call this function, which
could prove handy to people trying to do the right thing in faulty
drivers (if their fw/hw don't get in their way).
[1] http://mid.gmane.org/1390391564-18481-1-git-send-email-karl.beldan@gmail.com
[2] Commit: cf6bb79ad8 ("mac80211: Use appropriate TID for sending BAR, ADDBA and DELBA frames")
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Cc: Helmut Schaa <helmut.schaa@googlemail.com>
Cc: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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:
[<c1046e42>] warn_slowpath_common+0x72/0xa0
[<c1046f13>] warn_slowpath_fmt+0x33/0x40
[<fddffa17>] iwlagn_tx_skb+0xc47/0xce0 [iwldvm]
[<fddfcaa3>] iwlagn_mac_tx+0x23/0x40 [iwldvm]
[<fd8c98b6>] __ieee80211_tx+0xf6/0x3c0 [mac80211]
[<fd8cbe00>] ieee80211_tx+0xd0/0x100 [mac80211]
[<fd8cc176>] ieee80211_xmit+0x96/0xe0 [mac80211]
[<fd8cc578>] ieee80211_subif_start_xmit+0x348/0xc80 [mac80211]
[<c1445207>] dev_hard_start_xmit+0x337/0x6d0
[<c145eee9>] sch_direct_xmit+0xa9/0x210
[<c14462c0>] 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 <johannes.berg@intel.com>
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 <johannes.berg@intel.com>
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 <johannes.berg@intel.com>
Create the function ieee80211_remove_tid_tx to call
it from ___ieee80211_stop_tx_ba_session later.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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 <johannes.berg@intel.com>
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 <chaitanyatk@posedge.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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 <johannes.berg@intel.com>
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 <chunkeey@googlemail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
There are a few things that make the logging and
debugging in mac80211 less useful than it should
be right now:
* a lot of messages should be pr_info, not pr_debug
* wholesale use of pr_debug makes it require *both*
Kconfig and dynamic configuration
* there are still a lot of ifdefs
* the style is very inconsistent, sometimes the
sdata->name is printed in front
Clean up everything, introducing new macros and
separating out the station MLME debugging into
a new Kconfig symbol.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Johannes Berg
Michal Kazior
Felix Fietkau
Sara Sharon
Gregory Greenman
Emmanuel Grumbach
Liad Kaufman
Luciano Coelho
Karl Beldan
Chaitanya
Christian Lamparter