It is currently possible to have a race due to the station PS
unblock work like this:
* station goes to sleep with frames buffered in the driver
* driver blocks wakeup
* station wakes up again
* driver flushes/returns frames, and unblocks, which schedules
the unblock work
* unblock work starts to run, and checks that the station is
awake (i.e. that the WLAN_STA_PS_STA flag isn't set)
* we process a received frame with PM=1, setting the flag again
* ieee80211_sta_ps_deliver_wakeup() runs, delivering all frames
to the driver, and then clearing the WLAN_STA_PS_DRIVER and
WLAN_STA_PS_STA flags
In this scenario, mac80211 will think that the station is awake,
while it really is asleep, and any TX'ed frames should be filtered
by the device (it will know that the station is sleeping) but then
passed to mac80211 again, which will not buffer it either as it
thinks the station is awake, and eventually the packets will be
dropped.
Fix this by moving the clearing of the flags to exactly where we
learn about the situation. This creates a problem of reordering,
so introduce another flag indicating that delivery is being done,
this new flag also queues frames and is cleared only while the
spinlock is held (which the queuing code also holds) so that any
concurrent delivery/TX is handled correctly.
Reported-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
If the rate control algorithm uses a selection table, it
is leaked when the station is destroyed - fix that.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Reported-by: Christophe Prévotaux <cprevotaux@nltinc.com>
Fixes: 0d528d85c5 ("mac80211: improve the rate control API")
Cc: stable@vger.kernel.org # v3.10+
[add commit log entry, remove pointless NULL check]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The BUG_ON(!err) can't be triggered in the code path, so remove
it.
Signed-off-by: Zhao, Gang <gamerh2o@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The patch "mac80211: implement SMPS for AP" has caused kernel
oops at mesh STA if the peer mesh STA operates in sleep mode
and then becomes active mode. It can be easily reproduced by
setting the following commands at peer mesh STA:
iw mesh0 station set aa:bb:cc:dd:ee:ff mesh_power_mode deep
iw mesh0 station set aa:bb:cc:dd:ee:ff mesh_power_mode active
Kernel oops will happen at mesh STA aa:bb:cc:dd:ee:ff.
Fix this by avoiding SMPS for mesh mode.
Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Avoid leaking data by sending uninitialized memory and setting an
invalid (non-zero) fragment number (the sequence number is ignored
anyway) by setting the seq_ctrl field to zero.
Cc: stable@vger.kernel.org
Fixes: 3f52b7e328 ("mac80211: mesh power save basics")
Fixes: ce662b44ce ("mac80211: send (QoS) Null if no buffered frames")
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Consider the following (relatively unlikely) scenario:
1) station goes to sleep while frames are buffered in driver
2) driver blocks wakeup (until no more frames are buffered)
3) station wakes up again
4) driver unblocks wakeup
In this case, the current mac80211 code will do the following:
1) WLAN_STA_PS_STA set
2) WLAN_STA_PS_DRIVER set
3) - nothing -
4) WLAN_STA_PS_DRIVER cleared
As a result, no frames will be delivered to the client, even
though it is awake, until it sends another frame to us that
triggers ieee80211_sta_ps_deliver_wakeup() in sta_ps_end().
Since we now take the PS spinlock, we can fix this while at
the same time removing the complexity with the pending skb
queue function. This was broken since my commit 50a9432dae
("mac80211: fix powersaving clients races") due to removing
the clearing of WLAN_STA_PS_STA in the RX path.
While at it, fix a cleanup path issue when a station is
removed while the driver is still blocking its wakeup.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
There's a race condition in mac80211 because we add stations
to the internal lists after adding them to the driver, which
means that (for example) the following can happen:
1. a station connects and is added
2. first, it is added to the driver
3. then, it is added to the mac80211 lists
If the station goes to sleep between steps 2 and 3, and the
firmware/hardware records it as being asleep, mac80211 will
never instruct the driver to wake it up again as it never
realized it went to sleep since the RX path discarded the
frame as a "spurious class 3 frame", no station entry was
present yet.
Fix this by adding the station in software first, and only
then adding it to the driver. That way, any state that the
driver changes will be reflected properly in mac80211's
station state. The problematic part is the roll-back if the
driver fails to add the station, in that case a bit more is
needed. To not make that overly complex prevent starting BA
sessions in the meantime.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
There is a race between the TX path and the STA wakeup: while
a station is sleeping, mac80211 buffers frames until it wakes
up, then the frames are transmitted. However, the RX and TX
path are concurrent, so the packet indicating wakeup can be
processed while a packet is being transmitted.
This can lead to a situation where the buffered frames list
is emptied on the one side, while a frame is being added on
the other side, as the station is still seen as sleeping in
the TX path.
As a result, the newly added frame will not be send anytime
soon. It might be sent much later (and out of order) when the
station goes to sleep and wakes up the next time.
Additionally, it can lead to the crash below.
Fix all this by synchronising both paths with a new lock.
Both path are not fastpath since they handle PS situations.
In a later patch we'll remove the extra skb queue locks to
reduce locking overhead.
BUG: unable to handle kernel
NULL pointer dereference at 000000b0
IP: [<ff6f1791>] ieee80211_report_used_skb+0x11/0x3e0 [mac80211]
*pde = 00000000
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
EIP: 0060:[<ff6f1791>] EFLAGS: 00210282 CPU: 1
EIP is at ieee80211_report_used_skb+0x11/0x3e0 [mac80211]
EAX: e5900da0 EBX: 00000000 ECX: 00000001 EDX: 00000000
ESI: e41d00c0 EDI: e5900da0 EBP: ebe458e4 ESP: ebe458b0
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
CR0: 8005003b CR2: 000000b0 CR3: 25a78000 CR4: 000407d0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: ffff0ff0 DR7: 00000400
Process iperf (pid: 3934, ti=ebe44000 task=e757c0b0 task.ti=ebe44000)
iwlwifi 0000:02:00.0: I iwl_pcie_enqueue_hcmd Sending command LQ_CMD (#4e), seq: 0x0903, 92 bytes at 3[3]:9
Stack:
e403b32c ebe458c4 00200002 00200286 e403b338 ebe458cc c10960bb e5900da0
ff76a6ec ebe458d8 00000000 e41d00c0 e5900da0 ebe458f0 ff6f1b75 e403b210
ebe4598c ff723dc1 00000000 ff76a6ec e597c978 e403b758 00000002 00000002
Call Trace:
[<ff6f1b75>] ieee80211_free_txskb+0x15/0x20 [mac80211]
[<ff723dc1>] invoke_tx_handlers+0x1661/0x1780 [mac80211]
[<ff7248a5>] ieee80211_tx+0x75/0x100 [mac80211]
[<ff7249bf>] ieee80211_xmit+0x8f/0xc0 [mac80211]
[<ff72550e>] ieee80211_subif_start_xmit+0x4fe/0xe20 [mac80211]
[<c149ef70>] dev_hard_start_xmit+0x450/0x950
[<c14b9aa9>] sch_direct_xmit+0xa9/0x250
[<c14b9c9b>] __qdisc_run+0x4b/0x150
[<c149f732>] dev_queue_xmit+0x2c2/0xca0
Cc: stable@vger.kernel.org
Reported-by: Yaara Rozenblum <yaara.rozenblum@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com>
[reword commit log, use a separate lock]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
If a uAPSD service period ends with an MMPDU, we currently just
send that MMPDU, but it obviously won't get the EOSP bit set as
it doesn't have a QoS header. This contradicts the standard, so
add a QoS-nulldata frame after the MMPDU to properly terminate
the service period with a frame that has EOSP set.
Also fix a bug wrt. the TID for the MMPDU, it shouldn't be set
to 0 unconditionally but use the actual TID that was assigned.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When a response for PS-Poll or a uAPSD trigger frame is sent, the
more-data bit should be set according to 802.11-2012 11.2.1.5 h),
meaning that it should indicate more data on the relevant ACs
(delivery-enabled or nondelivery-enabled for uAPSD or PS-Poll.)
In, for example, the following scenario:
* 1 frame on VO queue (either in driver or in mac80211)
* at least 1 frame on VI queue (in the driver)
* both VO/VI are delivery-enabled
* uAPSD trigger frame received
The more-data flag to the driver would not be set, even though
it should be.
While fixing this, I noticed that we should really release frames
from multiple ACs where there's data buffered in the driver for
the corresponding TIDs.
To address all this, restructure the code a bit to consider all
ACs if we only release driver frames or only buffered frames.
This also addresses the more-data bug described above as now the
TIDs will all be marked as released, so the driver will have to
check the number of frames.
While at it, clarify some code and comments and remove the found
variable, replacing it with the appropriate sw/hw release check.
Reported-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Using ffs() for the PS-Poll release TID is wrong, it will cause
frames to be released in order 0 1 2 3 4 5 6 7 instead of the
correct 7 6 5 4 3 0 2 1. Fix this by adding a new function that
implements "highest priority TID" properly.
Reported-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When the station's TX latency data structures need to be
allocated, handle failures properly and also free all the
structures if there are any other problems.
Move the allocation code up so that allocation failures
don't trigger rate control algorithm calls.
Reported-by: ZHAO Gang <gamerh2o@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This is useful for debugging issues with drivers using this
function (erroneously), so add tracing for the API call.
Change-Id: Ice9d7eabb8fecbac188f0a741920d3488de700ec
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Teach sta_info_flush() to optionally also remove stations
from all VLANs associated with an AP interface to optimise
the station removal (in particular, synchronize_net().)
To not have to add the vlans argument throughout, do some
refactoring.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
There's no reason to have one synchronize_net() for each
removed station, refactor the code slightly to have just
a single synchronize_net() for all stations.
Note that this is currently useless as hostapd removes
stations one by one and this coalescing never happens.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
There's no reason to do this inside the sta key removal
since the keys can only be reached through the sta (and
not by the driver at all) so once the sta can no longer
be reached, the keys are safe.
This will allow further optimisation opportunities with
multiple stations.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
If we can assume that stations are never referenced by the
driver after sta_state returns (and this is true since the
previous iwlmvm patch and for all other drivers) then we
don't need to delay station destruction, and don't need to
play tricks with rcu_barrier() etc.
This should speed up some scenarios like hostapd shutdown.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The pointer should be cleared before synchronize_rcu() so that the
consequently dead station won't be found by any lookups in the TX
or RX paths.
Also check that the station is actually the one being removed, the
check is not needed because each 4-addr VLAN can only have a single
station and non-4-addr VLANs always have a NULL pointer there, but
the code is clearer this way (and we avoid the memory write.)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Currently, mac80211 allows drivers to keep RCU-protected station
references that are cleared when the station is removed from the
driver and consequently needs to synchronize twice, once before
removing the station from the driver (so it can guarantee that
the station is no longer used in TX towards the driver) and once
after the station is removed from the driver.
Add a new pre-RCU-synchronisation station removal operation to
the API to allow drivers to clear/invalidate their RCU-protected
station pointers before the RCU synchronisation.
This will allow removing the second synchronisation by changing
the driver API so that the driver may no longer assume a valid
RCU-protected pointer after sta_remove/sta_state returns.
The alternative to this would be to synchronize_rcu() in all the
drivers that currently rely on this behaviour (only iwlmvm) but
that would defeat the purpose.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Measure TX latency and jitter statistics per station per TID.
These Measurements are disabled by default and can be enabled
via debugfs.
Features included for each station's TID:
1. Keep count of the maximum and average latency of Tx frames.
2. Keep track of many frames arrived in a specific time range
(need to enable through debugfs and configure the bins ranges)
Signed-off-by: Matti Gottlieb <matti.gottlieb@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Add a new field to ieee80211_chanctx_conf to indicate
the min required channel configuration.
Tuning to a narrower channel might help reducing
the noise level and saving some power.
The min required channel definition is the max of
all min required channel definitions of the interfaces
bound to this channel context.
In AP mode, use 20MHz when there are no connected station.
When a new station is added/removed, calculate the new max
bandwidth supported by any of the stations (e.g. 80MHz when
80MHz and 40MHz stations are connected).
In other cases, simply use bss_conf.chandef as the
min required chandef.
Notify drivers about changes to this field by calling
drv_change_chanctx with a new CHANGE_MIN_WIDTH notification.
Signed-off-by: Eliad Peller <eliad@wizery.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Use put_unaligned_le16 in mesh_plink_frame_tx.
Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
802.11-2012 13.3.1 implicitly limits the mesh local link
ID range to that of AID, since for mesh PS the local link
ID must be indicated in the TIM IE, which only holds
IEEE80211_MAX_AID bits.
Also the code was allowing a local link ID of 0, but this
is not correct since that TIM bit is used for indicating
buffered mcast frames.
Generate a random, unique, link ID from 1 - 2007, and drop
a modulo conversion for the local link ID, but keep it for
the peer link ID in case he chose something > MAX_AID.
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When the driver requests to move to STATIC or DYNAMIC SMPS,
we send an action frame to each associated station and
reconfigure the channel context / driver.
Of course, non-MIMO stations are ignored.
The beacon isn't updated. The association response will
include the original capabilities. Stations that associate
while in non-OFF SMPS mode will get an action frame right
after association to inform them about our current state.
Note that we wait until the end of the EAPOL. Sending an
action frame before the EAPOL is finished can be an issue
for a few clients. Clients aren't likely to send EAPOL
frames in MIMO anyway.
When the SMPS configuration gets more permissive (e.g.
STATIC -> OFF), we don't wake up stations that are asleep
We remember that they don't know about the change and send
the action frame when they wake up.
When the SMPS configuration gets more restrictive (e.g.
OFF -> STATIC), we set the TIM bit for every sleeping STA.
uAPSD stations might send MIMO until they poll the action
frame, but this is for a short period of time.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
[fix vht streams loop, initialisation]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Previously the default mesh STA nonpeer power mode was
UNKNOWN (0) make the default mesh STA power mode ACTIVE,
to prevent unnecessary frame buffering while peering is
not yet complete. Fixes a panic in ath9k_htc when adding
stations from userspace, and mcast buffered frames are
later released.
Thanks to Bob Copeland for his help debugging this.
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Ben reports that kmemleak is saying TX aggregation TID
structs are leaked. Given his workload, I suspect that
they're leaked because stations are destroyed before
their aggregation sessions get a chance to start. Fix
this by simply freeing structs that are not used yet.
Reported-by: Ben Greear <greearb@candelatech.com>
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Instead of calling synchronize_net() for every key
on an interface or when a station is removed, do it
only once for all keys in both of these cases.
As a side-effect, removing station keys now always
calls synchronize_net() even if there are no keys,
which fixes an issue with station removal happening
in the driver while the station could still be used
for TX.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
It is possible that sta_info_recalc_tim() is called consecutively
without changing the station's tim bit. In such cases there is no
need to call the driver's set_tim() callback.
Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The irqsafe version ieee80211_sta_eosp_irqsafe() exists, but
drivers must not mix calls to any irqsafe/non-irqsafe function.
Both ath9k and iwlwifi, the likely first users of this interface,
use non-irqsafe RX/TX/TX status so must also use a non-irqsafe
version of this function. Since no driver uses the _irqsafe()
version, remove that.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
There is a corner case which wasn't being covered:
userspace may authenticate and allocate stations,
but still leave the peering up to the kernel.
Initialize the peering timer if the MPM is not in
userspace, in a path which is taken by both the kernel and
userspace when allocating stations.
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
During roaming, the crypto_tx_tailroom_needed_cnt counter
will often take values 2,1,0,1,2 because first keys are
removed and then new keys are added. This is inefficient
because during the 0->1 transition, synchronize_net must
be called to avoid packet races, although typically no
packets would be flowing during that time.
To avoid that, defer the decrement (2->1, 1->0) when keys
are removed (by half a second). This means the counter
will really have the values 2,2,2,3,4 ... 2, thus never
reaching 0 and having to do the 0->1 transition.
Note that this patch entirely disregards the drivers for
which this optimisation was done to start with, for them
the key removal itself will be expensive because it has
to synchronize_net() after the counter is incremented to
remove the key from HW crypto. For them the sequence will
look like this: 0,1,0,1,0,1,0,1,0 (*) which is clearly a
lot more inefficient. This could be addressed separately,
during key removal the 0->1->0 sequence isn't necessary.
(*) it starts at 0 because HW crypto is on, then goes to
1 when HW crypto is disabled for a key, then back to
0 because the key is deleted; this happens for both
keys in the example. When new keys are added, it goes
to 1 first because they're added in software; when a
key is moved to hardware it goes back to 0
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Instead of modifying the HT SMPS capability field
for stations, track the SMPS mode explicitly in a
new field in the station struct and use it in the
drivers that care about it. This simplifies the
code using it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
There's no need to use _irqsave() as the lock
is never used in interrupt context.
This also fixes a problem in the iwlwifi MVM
driver that calls spin_unlock_bh() within its
set_tim() callback.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
In my commit 1672c0e319
("mac80211: start auth/assoc timeout on frame status")
I broke auth/assoc timeout handling: in case we wait
for the TX status, it now leaves the timeout field set
to 0, which is a valid time and can compare as being
before now ("jiffies"). Thus, if the work struct runs
for some other reason, the auth/assoc is treated as
having timed out.
Fix this by introducing a separate "timeout_started"
variable that tracks whether the timeout has started
and is checked before timing out.
Additionally, for proper TX status handling the change
requires that the skb->dev pointer is set up for all
the frames, so set it up for all frames in mac80211.
Reported-by: Wojciech Dubowik <Wojciech.Dubowik@neratec.com>
Tested-by: Wojciech Dubowik <Wojciech.Dubowik@neratec.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The patch "mac80211: clean up mesh sta allocation warning"
moved some mesh initialization into a path which is only
called when the kernel handles peering. This causes a hang
when mac80211 tries to clean up a userspace-allocated
station entry and delete a timer which has never been
initialized.
To avoid this, only do any mesh sta peering teardown if
the kernel is actually handling it.
The same is true when quiescing before suspend.
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Add routines to
- maintain a PS mode for each peer and a non-peer PS mode
- indicate own PS mode in transmitted frames
- track neighbor STAs power modes
- buffer frames when neighbors are in PS mode
- add TIM and Awake Window IE to beacons
- release frames in Mesh Peer Service Periods
Add local_pm to sta_info to represent the link-specific power
mode at this station towards the remote station. When a peer
link is established, use the default power mode stored in mesh
config. Update the PS status if the peering status of a neighbor
changes.
Maintain a mesh power mode for non-peer mesh STAs. Set the
non-peer power mode to active mode during peering. Authenticated
mesh peering is currently not working when either node is
configured to be in power save mode.
Indicate the current power mode in transmitted frames. Use QoS
Nulls to indicate mesh power mode transitions.
For performance reasons, calls to the function setting the frame
flags are placed in HWMP routing routines, as there the STA
pointer is already available.
Add peer_pm to sta_info to represent the peer's link-specific
power mode towards the local station. Add nonpeer_pm to
represent the peer's power mode towards all non-peer stations.
Track power modes based on received frames.
Add the ps_data structure to ieee80211_if_mesh (for TIM map, PS
neighbor counter and group-addressed frame buffer).
Set WLAN_STA_PS flag for STA in PS mode to use the unicast frame
buffering routines in the tx path. Update num_sta_ps to buffer
and release group-addressed frames after DTIM beacons.
Announce the awake window duration in beacons if in light or
deep sleep mode towards any peer or non-peer. Create a TIM IE
similarly to AP mode and add it to mesh beacons. Parse received
Awake Window IEs and check TIM IEs for buffered frames.
Release frames towards peers in mesh Peer Service Periods. Use
the corresponding trigger frames and monitor the MPSP status.
Append a QoS Null as trigger frame if neccessary to properly end
the MPSP. Currently, in HT channels MPSPs behave imperfectly and
show large delay spikes and frame losses.
Signed-off-by: Marco Porsch <marco@cozybit.com>
Signed-off-by: Ivan Bezyazychnyy <ivan.bezyazychnyy@gmail.com>
Signed-off-by: Mike Krinkin <krinkin.m.u@gmail.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This refactoring fixes a "scheduling while atomic" warning
when allocating a mesh station entry while holding the RCU
read lock. Fix this by creating a new function
mesh_sta_info_get(), which correctly handles the locking
and returns under RCU.
Also move some unnecessarily #ifdefed mesh station init
code from sta_info_alloc() to __mesh_sta_info_alloc().
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
[change code flow to make sparse happy]
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>
If there are VLANs, stopping an AP is inefficient as it
calls rcu_barrier() once for each interface (the VLANs
and the AP itself). Optimise this by moving rcu_barrier()
out of the station cleanups and calling it only once for
all interfaces combined.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The last fixes re-added the RCU synchronize penalty
on roaming to fix the races. Split up sta_info_flush()
now to get rid of that again, and let managed mode
(and only it) delay the actual destruction.
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When all interfaces have been removed, there can't
be any stations left over, so there's no need to
flush again. Remove this, and all code associated
with it, which also simplifies the function.
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This is a very old bug, but there's nothing that prevents the
timer from running while the module is being removed when we
only do del_timer() instead of del_timer_sync().
The timer should normally not be running at this point, but
it's not clearly impossible (or we could just remove this.)
Cc: stable@vger.kernel.org
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Unfortunately, commit b22cfcfcae, intended to speed up roaming
by avoiding the synchronize_rcu() broke AP/mesh modes as it moved
some code into that work item that will still call into the driver
at a time where it's no longer expected to handle this: after the
AP or mesh has been stopped.
To fix this problem remove the per-station work struct, maintain a
station cleanup list instead and flush this list when stations are
flushed. To keep this patch smaller for stable, do this when the
stations are flushed (sta_info_flush()). This unfortunately brings
back the original roaming delay; I'll fix that again in a separate
patch.
Also, Ben reported that the original commit could sometimes (with
many interfaces) cause long delays when an interface is set down,
due to blocking on flush_workqueue(). Since we now maintain the
cleanup list, this particular change of the original patch can be
reverted.
Cc: stable@vger.kernel.org [3.7]
Reported-by: Ben Greear <greearb@candelatech.com>
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
