iwlwifi: mvm: generalize the other-scan stopping code

Instead of hardcoding the differences between UMAC scans and LMAC
scans (which in this case is the number of simultaneous scans that can
run), introduce a max_scans variable and stop scans of the other type
(i.e. stop sched scan if regular scan is being attempted and
vice-versa) if the number of running scans reached the maximum.

Add a function that checks if the maximum number of scans was reached
and stops the appropriate scan to make room for the new scan.

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/mvm/fw-api-scan.h b/drivers/net/wireless/iwlwifi/mvm/fw-api-scan.h
index d6cced4..69daa4e 100644
--- a/drivers/net/wireless/iwlwifi/mvm/fw-api-scan.h
+++ b/drivers/net/wireless/iwlwifi/mvm/fw-api-scan.h
@@ -6,7 +6,7 @@
  * GPL LICENSE SUMMARY
  *
  * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
- * Copyright(c) 2013 - 2014 Intel Mobile Communications GmbH
+ * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License as
@@ -32,7 +32,7 @@
  * BSD LICENSE
  *
  * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
- * Copyright(c) 2013 - 2014 Intel Mobile Communications GmbH
+ * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -582,7 +582,11 @@
 	u8 ver;
 } __packed;
 
-#define IWL_MVM_MAX_SIMULTANEOUS_SCANS 8
+/* The maximum of either of these cannot exceed 8, because we use an
+ * 8-bit mask (see IWL_MVM_SCAN_MASK in mvm.h).
+ */
+#define IWL_MVM_MAX_UMAC_SCANS 8
+#define IWL_MVM_MAX_LMAC_SCANS 1
 
 enum scan_config_flags {
 	SCAN_CONFIG_FLAG_ACTIVATE			= BIT(0),