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>
Simplify the use of #ifdef CONFIG_MAC80211_HT_DEBUG/#endif
by adding a logging macro to encapsulate the test.
Convert the appropriate uses too.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Standardize the debugging to be able to use dynamic_debug.
Coalesce formats, align arguments.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
In commit 12d3952fc4
("mac80211: optimize aggregation session timeout handling")
two bugs were introduced:
1) RCU usage was completely broken since no locks are held
2) the timer must not rearm when agg session is stopping
Reported-and-tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
mac80211 currently only supports one hardware queue
per AC. This is already problematic for off-channel
uses since if we go off channel while the BE queue
is full and then try to send an off-channel frame
the frame will never go out. This will become worse
when we support multi-channel since then a queue on
one channel might be full, but we have to stop the
software queue for all channels. That is obviously
not desirable.
To address this problem allow drivers to register
more hardware queues, and allow them to map them to
virtual interfaces. When they stop a hardware queue
the corresponding AC software queues on the correct
interfaces will be stopped as well. Additionally,
there's an off-channel queue to solve that problem
and a per-interface after-DTIM beacon queue. This
allows drivers to manage software queues closer to
how the hardware works.
Currently, there's a limit of 16 hardware queues.
This may or may not be sufficient, we can adjust it
as needed.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Calling mod_timer from the rx/tx hotpath is somewhat expensive, and the
timeout doesn't need to be so precise.
Switch to a different strategy: Schedule the timer initially, store jiffies
of all last rx/tx activity which would previously modify the timer, and
let the timer re-arm itself after checking the last rx/tx timestamp.
Make the session timers deferrable to avoid causing extra wakeups on systems
running on battery.
This visibly reduces CPU load under high network load on small embedded
systems.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Currently code allows three (HT_AGG_MAX_RETRIES) unanswered addba
requests. When this limit is reached aggregation is turned off for
given TID permanently. This doesn't seem right: three requests is
not that much, some 'blackout' can happen, but effect of it affects
whole connection indefinitely.
This patch increases number of retries to 15. Also, when there have
been 3 or more retries it splits further retries apart by 15 seconds
instead of sending them in very short period of time.
Signed-off-by: Nikolay Martynov <mar.kolya@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Currently BAR, ADDBA and DELBA frames are always sent using AC_VO. If
the TID for which a BA session is established is assigned to a different
queue BAR, ADDBA and DELBA frames can "overtake" frames of the according
BA session.
Hence, always put BA session related frames into the same queue as the
BA sessions data frames.
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When a station leaves suddenly while ampdu traffic to that station is still
running, there is a possibility that the ampdu pending queues are not freed due
to a race condition leading to memory leaks. In '__sta_info_destroy' when we
attempt to destroy the ampdu sessions in 'ieee80211_sta_tear_down_BA_sessions',
the driver calls 'ieee80211_stop_tx_ba_cb_irqsafe' to delete the ampdu
structures (tid_tx) and splice the pending queues and this job gets queued in
sdata workqueue. However, the sta entry can get destroyed before the above work
gets scheduled and hence the race.
Purging the queues and freeing the tid_tx to avoid the leak. The better solution
would be to fix the race, but that can be taken up in a separate patch.
Signed-off-by: Nishant Sarmukadam <nishants@marvell.com>
Signed-off-by: Yogesh Ashok Powar <yogeshp@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Emmanuel noticed that when mac80211 stops the queues
for aggregation that can leave a packet pending. This
packet will be given to the driver after the AMPDU
callback, but as a non-aggregated packet which messes
up the sequence number etc.
I also noticed by looking at the code that if packets
are being processed while we clear the WANT_START bit,
they might see it cleared already and queue up on
tid_tx->pending. If the driver then rejects the new
aggregation session we leak the packet.
Fix both of these issues by changing this code to not
stop the queues at all. Instead, let packets queue up
on the tid_tx->pending queue instead of letting them
get to the driver, and add code to recover properly
in case the driver rejects the session.
(The patch looks large because it has to move two
functions to before their new use.)
Cc: stable@vger.kernel.org
Reported-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The HT mode is set by iw (previous patchsets).
The interface is set into the specified HT mode.
HT mode and capabilities are announced in beacons.
If we add a station that uses HT also, the fastest matching HT mode will
be used for transmission. That means if we are using HT40+ and we add a station
running on HT40-, we would transfer at HT20.
If we join an IBSS with HT40, but the secondary channel is not
available, we will fall back into HT20 as well.
Allow frame aggregation to start in IBSS mode.
Signed-off-by: Alexander Simon <an.alexsimon@googlemail.com>
[siwu@hrz.tu-chemnitz.de: Updates]
* remove implicit channel_type enum assumptions
* use rate_control_rate_init() if channel type changed
* remove channel flags check
* activate HT IBSS feature support
* slightly reword commit message
* rebase on wireless-testing
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
* Follow 802.11n-2009 9.13.3.1 for protection mode and ADDBA
* Send ADDBA only to HT STAs - implement 11.5.1.1 partially
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This fixes frequent WARN_ONs when using AP VLAN + aggregation, as these vifs
are virtual and not registered with drivers.
Use sta_info_get_bss instead of sta_info_get in aggregation callbacks, so
that these callbacks can find the station entry when called with the AP vif.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Currently tx aggregation is not being timed out even if timeout is
specified when aggregation is opened. Tx tid stays active until delba
arrives from recipient (i.e. recipient times out tid when it is
inactive).
The problem with this approach is that delba can get lost in the air
and tx tid will stay perpetually opened on the originator while closed
on recipient thus all data sent via this tid will be lost.
This patch implements tx tid timeouting in way very similar to rx tid
timeouting.
Signed-off-by: Nikolay Martynov <mar.kolya@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When a packet is supposed to sent be as an a-MPDU, mac80211 sets
IEEE80211_TX_CTL_AMPDU to let the driver know. On the other
hand, mac80211 configures the driver for aggregration with the
ampdu_action callback.
There is race between these two mechanisms since the following
scenario can occur when the BA agreement is torn down:
Tx softIRQ drv configuration
========== =================
check OPERATIONAL bit
Set the TX_CTL_AMPDU bit in the packet
clear OPERATIONAL bit
stop Tx AGG
Pass Tx packet to the driver.
In that case the driver would get a packet with TX_CTL_AMPDU set
although it has already been notified that the BA session has been
torn down.
To fix this, we need to synchronize all the Qdisc activity after we
cleared the OPERATIONAL bit. After that step, all the following
packets will be buffered until the driver reports it is ready to get
new packets for this RA / TID. This buffering allows not to run into
another race that would send packets with TX_CTL_AMPDU unset while
the driver hasn't been requested to tear down the BA session yet.
This race occurs in practice and iwlwifi complains with a WARN_ON
when it happens.
Cc: stable@kernel.org
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
If addBA responses comes in just after addba_resp_timer has
expired mac80211 will still accept it and try to open the
aggregation session. This causes drivers to be confused and
in some cases even crash.
This patch fixes the race condition and makes sure that if
addba_resp_timer has expired addBA response is not longer
accepted and we do not try to open half-closed session.
Cc: stable@vger.kernel.org
Signed-off-by: Nikolay Martynov <mar.kolya@gmail.com>
[some adjustments]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Nikolay noticed (by code review) that mac80211 can
attempt to stop an aggregation session while it is
already being stopped. So to fix it, check whether
stop is already being done and bail out if so.
Also move setting the STOPPING state into the lock
so things are properly atomic.
Cc: stable@vger.kernel.org
Reported-by: Nikolay Martynov <mar.kolya@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: Ashok Nagarajan <anagar6@uic.edu>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
These files are non modular, but need to export symbols using
the macros now living in export.h -- call out the include so
that things won't break when we remove the implicit presence
of module.h from everywhere.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
The flaglock in struct sta_info has long been
something that I wanted to get rid of, this
finally does the conversion to atomic bitops.
The conversion itself is straight-forward in
most places, a few things needed to change a
bit since we can no longer use multiple bits
at the same time.
On x86-64, this is a fairly significant code
size reduction:
text data bss dec hex
427861 23648 1008 452517 6e7a5 before
425383 23648 976 450007 6ddd7 after
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
To properly maintain the peer's block ack window, the driver needs to be
able to control the new starting sequence number that is sent along with
the BlockAckReq frame.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When this flag is set, Tx A-MPDU sessions will not be started by
mac80211. This flag is required for devices that support Tx A-MPDU setup
in hardware.
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Removing unnecessary messages saves code and text.
Site specific OOM messages are duplications of a generic MM
out of memory message and aren't really useful, so just
delete them.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
While at it also fix the indention of the other IEEE80211_BAR_CTRL_ defines.
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
If we receive an ADDBA response with status code 0 and a buf_size of 0
we should stop the TX BA session as otherwise we'll end up queuing
frames in ieee80211_tx_prep_agg forever instead of sending them out as
non AMPDUs.
This fixes a problem with AVM Fritz Stick N wireless devices where
frames to this device are not transmitted anymore by mac80211.
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1446 commits)
macvlan: fix panic if lowerdev in a bond
tg3: Add braces around 5906 workaround.
tg3: Fix NETIF_F_LOOPBACK error
macvlan: remove one synchronize_rcu() call
networking: NET_CLS_ROUTE4 depends on INET
irda: Fix error propagation in ircomm_lmp_connect_response()
irda: Kill set but unused variable 'bytes' in irlan_check_command_param()
irda: Kill set but unused variable 'clen' in ircomm_connect_indication()
rxrpc: Fix set but unused variable 'usage' in rxrpc_get_transport()
be2net: Kill set but unused variable 'req' in lancer_fw_download()
irda: Kill set but unused vars 'saddr' and 'daddr' in irlan_provider_connect_indication()
atl1c: atl1c_resume() is only used when CONFIG_PM_SLEEP is defined.
rxrpc: Fix set but unused variable 'usage' in rxrpc_get_peer().
rxrpc: Kill set but unused variable 'local' in rxrpc_UDP_error_handler()
rxrpc: Kill set but unused variable 'sp' in rxrpc_process_connection()
rxrpc: Kill set but unused variable 'sp' in rxrpc_rotate_tx_window()
pkt_sched: Kill set but unused variable 'protocol' in tc_classify()
isdn: capi: Use pr_debug() instead of ifdefs.
tg3: Update version to 3.119
tg3: Apply rx_discards fix to 5719/5720
...
Fix up trivial conflicts in arch/x86/Kconfig and net/mac80211/agg-tx.c
as per Davem.
This adds sparse RCU annotations to most of
mac80211, only the mesh code remains to be
done.
Due the the previous patches, the annotations
are pretty simple. The only thing that this
actually changes is removing the RCU usage of
key->sta in debugfs since this pointer isn't
actually an RCU-managed pointer (it only has
a single assignment done before the key even
goes live). As that is otherwise harmless, I
decided to make it part of this patch.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
During my quest to make mac80211 not have any RCU
warnings from sparse, I came across the a-MPDU code
again and it wasn't quite clear why it isn't racy.
So instead of assigning the tid_tx array with just
the spinlock held in ieee80211_start_tx_ba_session
use a separate temporary array protected only by
the spinlock and protect all assignments to the
"live" array by both the spinlock and the mutex so
that other code is easily verified to be correct.
Due to pointer assignment atomicity I don't think
this is a real issue, but I'm not sure, especially
on Alpha the current code might be problematic.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The rcu callback kfree_tid_tx() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(kfree_tid_tx).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: "David S. Miller" <davem@davemloft.net>
Currently, mac80211 always advertises that it may send
up to 64 subframes in an aggregate. This is fine, since
it's the max, but might as well be set to zero instead
since it doesn't have any information.
However, drivers might have that information, so allow
them to set a variable giving it, which will then be
used. The default of zero will be fine since to the
peer that means we don't know and it will just use its
own limit for the buffer size.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The aggregation code currently doesn't implement the
buffer size negotiation. It will always request a max
buffer size (which is fine, if a little pointless, as
the mac80211 code doesn't know and might just use 0
instead), but if the peer requests a smaller size it
isn't possible to honour this request.
In order to fix this, look at the buffer size in the
addBA response frame, keep track of it and pass it to
the driver in the ampdu_action callback when called
with the IEEE80211_AMPDU_TX_OPERATIONAL action. That
way the driver can limit the number of subframes in
aggregates appropriately.
Note that this doesn't fix any drivers apart from the
addition of the new argument -- they all need to be
updated separately to use this variable!
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Allow drivers or rate control algorithms to specify BlockAck session
timeout when initiating an ADDBA transaction. This is useful in cases
where maintaining persistent BA sessions does not incur any overhead.
The current timeout value of 5000 TUs is retained for all non ath9k/ath9k_htc
drivers.
Signed-off-by: Sujith Manoharan <Sujith.Manoharan@atheros.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When roaming while we have active BA session,
we can end up transmitting delBA frames to
the old AP while we're already on the new AP's
channel, which can cause warnings.
Simply avoid sending those frames, but still
tear down the internal session state, since
they are not really necessary anyway as we
will implicitly disassociate when sending the
association to the new AP.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
We never delete the addBA response timer, which
is typically fine, but if the station it belongs
to is deleted very quickly after starting the BA
session, before the peer had a chance to reply,
the timer may fire after the station struct has
been freed already. Therefore, we need to delete
the timer in a suitable spot -- best when the
session is being stopped (which will happen even
then) in which case the delete will be a no-op
most of the time.
I've reproduced the scenario and tested the fix.
This fixes the crash reported at
http://mid.gmane.org/4CAB6F96.6090701@candelatech.com
Cc: stable@kernel.org
Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Even before the recent changes, the documentation
for TX aggregation was somewhat out of date. Update
it and also add documentation for the RX side.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
To prepare for allowing drivers to sleep in
ampdu_action, change the locking in the TX
aggregation code to use the mutex the RX part
already uses. The spinlock is still necessary
around some code to avoid races with TX, but
now we can also synchronize_net() to avoid
getting an inconsistent sequence number.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Karl Beldan