iwlwifi: mvm: fix debugfs restart if fw_restart is disabled

If fw_restart is disabled, using the fw_restart debugfs
file will enable fw_restart and then send the failing
command, but this still frequently fails restart because
it resets fw_restart afterwards and is thus racy.

Fix this by tracking fw_restart separately and allowing
"always restart", "never restart" and "restart N times".

Signed-off-by: Eran Harary <eran.harary@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/mvm/debugfs.c b/drivers/net/wireless/iwlwifi/mvm/debugfs.c
index 347aa1c..15d52ba 100644
--- a/drivers/net/wireless/iwlwifi/mvm/debugfs.c
+++ b/drivers/net/wireless/iwlwifi/mvm/debugfs.c
@@ -597,20 +597,19 @@
 					  size_t count, loff_t *ppos)
 {
 	struct iwl_mvm *mvm = file->private_data;
-	bool restart_fw = iwlwifi_mod_params.restart_fw;
 	int ret;
 
-	iwlwifi_mod_params.restart_fw = true;
-
 	mutex_lock(&mvm->mutex);
 
+	/* allow one more restart that we're provoking here */
+	if (mvm->restart_fw >= 0)
+		mvm->restart_fw++;
+
 	/* take the return value to make compiler happy - it will fail anyway */
 	ret = iwl_mvm_send_cmd_pdu(mvm, REPLY_ERROR, CMD_SYNC, 0, NULL);
 
 	mutex_unlock(&mvm->mutex);
 
-	iwlwifi_mod_params.restart_fw = restart_fw;
-
 	return count;
 }