In the scan state machine, the wl1271_mutex is unlocked first then relocked,
and then the scan state variables are modified.

This makes it possible for ieee80211_scan_complete to be called twice in some
scenarios, as the scan completion event from the firmware may be processed
while the mutex is unlocked.

To fix the issue, move the ieee80211_scan_complete call last in the function.
This is generally safer, but there still may be issues is functions calling
the scan state machine rely on states checked before the unlocking of the
global mutex.

(forward ported from 2.6.32 -- this is not strictly needed anymore, because
the mutex doesn't need to be unlocked anymore, but I'm applying this change
anyway, so that the call to ieee80211_scan_complete is in the same place)
Signed-off-by: NJuuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: NSaravanan Dhanabal <ext-saravanan.dhanabal@nokia.com>
Signed-off-by: NLuciano Coelho <luciano.coelho@nokia.com>

With the scan callback now being callable from
any context, these unlocks/locks can go away.
This makes the code easier to understand, since
callers of these functions must no longer be
aware that the mutex may be dropped.

As Stanislaw is working on iwlwifi scanning, I
didn't change it to take advantage of the new
mac80211 semantics.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

We were always using the max transmit power when scanning.  Now we use the
values passed to the driver by the mac80211 stack, so that we comply with
regulations.
Signed-off-by: NLuciano Coelho <luciano.coelho@nokia.com>
Reviewed-by: NSaravanan Dhanabal <ext-saravanan.dhanabal@nokia.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This patch is a complete rewrite of the scanning code.  It now includes a
state machine to scan all four possible sets of channels independently:
2.4GHz active, 2.4GHz passive, 5GHz active and 5GHz passive.  The wl1271
firmware doesn't allow these sets to be mixed, so up to several scan commands
have to be issued.  This patch also allows scanning more than 24 channels per
set, by breaking the sets into smaller parts if needed (the firmware can scan
a maximum of 24 channels at a time).

Previously, the scanning code was erroneously scanning all channels possible
actively, not complying with the CRDA values.  This is also fixed with this
patch.
Signed-off-by: NLuciano Coelho <luciano.coelho@nokia.com>
Reviewed-by: NSaravanan Dhanabal <ext-saravanan.dhanabal@nokia.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The scanning code is going to get a bit more complex, with proper support for
active/passive scans together with 2.4GHz and 5GHz.  In the future, also a
new type of scan (periodic scan) will be added.  When all this is
implemented, the code is going to be much more complex, so we'd better
separate it into a separate file.

This patch doesn't have any impact on functionality.
Signed-off-by: NLuciano Coelho <luciano.coelho@nokia.com>
Reviewed-by: NSaravanan Dhanabal <ext-saravanan.dhanabal@nokia.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>