iwlwifi: mvm: don't lock mutex in RCU critical section

We cannot lock a mutex while we're in an RCU critical section. At
the same time, we're accessing data structures that are protected
by the mvm->mutex anyway, so just move the entire locking here to
use only that.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210411124417.4d27bd36e10e.I1fd8e8fe442c41a5deaa560452b598ed7a60ada5@changeidSigned-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c

 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
- * Copyright (C) 2012-2014, 2018-2020 Intel Corporation
+ * Copyright (C) 2012-2014, 2018-2021 Intel Corporation
  * Copyright (C) 2013-2015 Intel Mobile Communications GmbH
  * Copyright (C) 2016-2017 Intel Deutschland GmbH
  */
@@ -1210,10 +1210,10 @@ static int _iwl_dbgfs_inject_beacon_ie(struct iwl_mvm *mvm, char *bin, int len)
 			IWL_UCODE_TLV_API_NEW_BEACON_TEMPLATE))
 		return -EINVAL;
 
-	rcu_read_lock();
+	mutex_lock(&mvm->mutex);
 
 	for (i = 0; i < NUM_MAC_INDEX_DRIVER; i++) {
-		vif = iwl_mvm_rcu_dereference_vif_id(mvm, i, true);
+		vif = iwl_mvm_rcu_dereference_vif_id(mvm, i, false);
 		if (!vif)
 			continue;
 
@@ -1253,18 +1253,16 @@ static int _iwl_dbgfs_inject_beacon_ie(struct iwl_mvm *mvm, char *bin, int len)
 				 &beacon_cmd.tim_size,
 				 beacon->data, beacon->len);
 
-	mutex_lock(&mvm->mutex);
 	iwl_mvm_mac_ctxt_send_beacon_cmd(mvm, beacon, &beacon_cmd,
 					 sizeof(beacon_cmd));
 	mutex_unlock(&mvm->mutex);
 
 	dev_kfree_skb(beacon);
 
-	rcu_read_unlock();
 	return 0;
 
 out_err:
-	rcu_read_unlock();
+	mutex_unlock(&mvm->mutex);
 	return -EINVAL;
 }