According to RCU_INIT_POINTER()'s block comment 3.a, it can be used if
"3.   The referenced data structure has already been exposed to readers either
at compile time or via rcu_assign_pointer() -and-
 a.   You have not made -any- reader-visible changes to this structure since
then".

This case fulfills the conditions above because between the rcu_dereference()
call (cvif = rcu_dereference(ar->beacon_iter);) and the rcu_assign_pointer()
call there is no update of the "cvif" variable.
Therefore, this patch makes the replacement.

The following Coccinelle semantic patch was used:
@@
identifier v;
@@

v = rcu_dereference(...);
... when != rcu_dereference(...);
    when != v = ...;
    when != (<+...v...+>)++;
    when != \(memcpy\|memset\)(...);
(
- rcu_assign_pointer
+ RCU_INIT_POINTER
  (..., v);
|
 if(...) {
... when != v = ...;
- rcu_assign_pointer
+ RCU_INIT_POINTER
  (..., v);
... when any
 }
)

Because there are cases where between a “rcu_dereference()” call and a
“rcu_assign_pointer()” call might be updates of the value that interests us,
the Coccinelle semantic patch ignores them and replaces with
"RCU_INIT_POINTER()" only when the update is not happening.
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Acked-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Setup the channel context correctly. Not doing this was
causing beacon loss in a P2P-GO/STA concurrent setup.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Canek Peláez Valdés <canek@ciencias.unam.mx>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

If a new context is being added in addition to the current one,
then send the ASSIGN event to abort a running scan since
the addition of a context is usually followed by VIF
assignment and further operations.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

There is no reason why managed/p2p interfaces have to
be limited to one. IBSS is the only type that needs
a restriction.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

This will be useful in handling addition/change of new
channel contexts.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Move it inside a CONFIG_ATH9K_CHANNEL_CONTEXT ifdef
since it is not needed otherwise.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

This was introduced in an earlier patch to handle
a compilation warning, but since the channel context
code has been mostly isolated, this is not required now.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

chanctx_work and next_chan are required only when
CONFIG_ATH9K_CHANNEL_CONTEXT is enabled.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Finally move the 'offchannel' instance in ath_softc
inside a CONFIG_ATH9K_CHANNEL_CONTEXT cage. The offchannel
usage in ath9k_calculate_iter_data() is closed off with
an ifdef for now, since the state/opmode calculation is
common for both the channel context mode and the normal mode.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

ath9k_vif_iter() was earlier used as an iterator
routine when calling a mac80211 utility. This is no
longer the case and hence we can mention the argument
type explicitly.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

ath_chanctx_check_active() is required only when channel contexts
are used. Make sure that it is not called in normal usage.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

This patch adds a routine to setup the offchannel
instance in ath_softc.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Introduce a function that handles queues in channel
context mode.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Using these wrappers allows us to move the 'sched'
variable in ath_softc inside CONFIG_ATH9K_CHANNEL_CONTEXT.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

These routines are required only when
CONFIG_ATH9K_CHANNEL_CONTEXT is enabled.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Check if channel context usage is enabled before
calling ath_chanctx_event() from various parts of the
driver. Also, make sure that ath_chanctx_event() is
compiled only when CONFIG_ATH9K_CHANNEL_CONTEXT is
enabled.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Use CONFIG_ATH9K_CHANNEL_CONTEXT to exclude:

ath_scan_complete()
ath_roc_complete()
ath_offchannel_next()
ath_scan_next_channel()
ath_scan_channel_duration()
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Use CONFIG_ATH9K_CHANNEL_CONTEXT to exclude more functions:

ath_offchannel_channel_change()
ath_scan_channel_start()
ath_scan_send_probe()
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Exclude these functions when CONFIG_ATH9K_CHANNEL_CONTEXT is not
enabled:

ath_chanctx_send_vif_ps_frame()
ath_chanctx_send_ps_frame()
ath_chanctx_defer_switch()
ath_chanctx_set_next()
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Rename the callback from ath9k_chanctx_force_active()
to ath9k_mgd_prepare_tx(). Also, move it to main.c and
group it with the other callbacks.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Also compile it conditionally based on
CONFIG_ATH9K_CHANNEL_CONTEXT.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Setup the offchannel/sched timers and the chanctx work
inside the new function.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

The carl9170_op_ampdu_action() function is used only by the mac80211
framework.
Since the mac80211 already takes care of checks and properly serializing
calls to the driver's function there is no need for the driver to do the same
thing.
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

This patch ensures that the module parameter "use_chanctx" is
visible only when CONFIG_ATH9K_CHANNEL_CONTEXT is selected.
Also register the channel context callbacks with mac80211 only
when it is explicitly enabled and compile them out of the driver
when CONFIG_ATH9K_CHANNEL_CONTEXT is not selected.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Use CONFIG_ATH9K_CHANNEL_CONTEXT to conditionally
compile P2P-PS code.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Channel contexts are supported only for P2P right now,
so make sure that the 'normal' path remains unaffected
by using a config option. This will also reduce the size
of the driver.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Add a few statements to debug channel context operation.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

This reduces clutter in main.c
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>