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/* Copyright (c) 2016-2017 The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include "storm-watch.h"
/**
* is_storming(): Check if an event is storming
*
* @data: Data for tracking an event storm
*
* The return value will be true if a storm has been detected and
* false if a storm was not detected.
*/
bool is_storming(struct storm_watch *data)
{
ktime_t curr_kt, delta_kt;
bool is_storming = false;
if (!data)
return false;
if (!data->enabled)
return false;
/* max storm count must be greater than 0 */
if (data->max_storm_count <= 0)
return false;
/* the period threshold must be greater than 0ms */
if (data->storm_period_ms <= 0)
return false;
mutex_lock(&data->storm_lock);
curr_kt = ktime_get_boottime();
delta_kt = ktime_sub(curr_kt, data->last_kt);
if (ktime_to_ms(delta_kt) < data->storm_period_ms)
data->storm_count++;
else
data->storm_count = 0;
if (data->storm_count > data->max_storm_count) {
is_storming = true;
data->storm_count = 0;
}
data->last_kt = curr_kt;
mutex_unlock(&data->storm_lock);
return is_storming;
}
void reset_storm_count(struct storm_watch *data)
{
mutex_lock(&data->storm_lock);
data->storm_count = 0;
mutex_unlock(&data->storm_lock);
}
void update_storm_count(struct storm_watch *data, int max_count)
{
if (!data)
return;
mutex_lock(&data->storm_lock);
data->max_storm_count = max_count;
mutex_unlock(&data->storm_lock);
}
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