linux-stable/drivers/watchdog/watchdog_pretimeout.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

215 lines
4.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2015-2016 Mentor Graphics
*/
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/watchdog.h>
#include "watchdog_pretimeout.h"
/* Default watchdog pretimeout governor */
static struct watchdog_governor *default_gov;
/* The spinlock protects default_gov, wdd->gov and pretimeout_list */
static DEFINE_SPINLOCK(pretimeout_lock);
/* List of watchdog devices, which can generate a pretimeout event */
static LIST_HEAD(pretimeout_list);
struct watchdog_pretimeout {
struct watchdog_device *wdd;
struct list_head entry;
};
/* The mutex protects governor list and serializes external interfaces */
static DEFINE_MUTEX(governor_lock);
/* List of the registered watchdog pretimeout governors */
static LIST_HEAD(governor_list);
struct governor_priv {
struct watchdog_governor *gov;
struct list_head entry;
};
static struct governor_priv *find_governor_by_name(const char *gov_name)
{
struct governor_priv *priv;
list_for_each_entry(priv, &governor_list, entry)
if (sysfs_streq(gov_name, priv->gov->name))
return priv;
return NULL;
}
int watchdog_pretimeout_available_governors_get(char *buf)
{
struct governor_priv *priv;
int count = 0;
mutex_lock(&governor_lock);
list_for_each_entry(priv, &governor_list, entry)
count += sprintf(buf + count, "%s\n", priv->gov->name);
mutex_unlock(&governor_lock);
return count;
}
int watchdog_pretimeout_governor_get(struct watchdog_device *wdd, char *buf)
{
int count = 0;
spin_lock_irq(&pretimeout_lock);
if (wdd->gov)
count = sprintf(buf, "%s\n", wdd->gov->name);
spin_unlock_irq(&pretimeout_lock);
return count;
}
int watchdog_pretimeout_governor_set(struct watchdog_device *wdd,
const char *buf)
{
struct governor_priv *priv;
mutex_lock(&governor_lock);
priv = find_governor_by_name(buf);
if (!priv) {
mutex_unlock(&governor_lock);
return -EINVAL;
}
spin_lock_irq(&pretimeout_lock);
wdd->gov = priv->gov;
spin_unlock_irq(&pretimeout_lock);
mutex_unlock(&governor_lock);
return 0;
}
void watchdog_notify_pretimeout(struct watchdog_device *wdd)
{
unsigned long flags;
spin_lock_irqsave(&pretimeout_lock, flags);
if (!wdd->gov) {
spin_unlock_irqrestore(&pretimeout_lock, flags);
return;
}
wdd->gov->pretimeout(wdd);
spin_unlock_irqrestore(&pretimeout_lock, flags);
}
EXPORT_SYMBOL_GPL(watchdog_notify_pretimeout);
int watchdog_register_governor(struct watchdog_governor *gov)
{
struct watchdog_pretimeout *p;
struct governor_priv *priv;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
mutex_lock(&governor_lock);
if (find_governor_by_name(gov->name)) {
mutex_unlock(&governor_lock);
kfree(priv);
return -EBUSY;
}
priv->gov = gov;
list_add(&priv->entry, &governor_list);
if (!strncmp(gov->name, WATCHDOG_PRETIMEOUT_DEFAULT_GOV,
WATCHDOG_GOV_NAME_MAXLEN)) {
spin_lock_irq(&pretimeout_lock);
default_gov = gov;
list_for_each_entry(p, &pretimeout_list, entry)
if (!p->wdd->gov)
p->wdd->gov = default_gov;
spin_unlock_irq(&pretimeout_lock);
}
mutex_unlock(&governor_lock);
return 0;
}
EXPORT_SYMBOL(watchdog_register_governor);
void watchdog_unregister_governor(struct watchdog_governor *gov)
{
struct watchdog_pretimeout *p;
struct governor_priv *priv, *t;
mutex_lock(&governor_lock);
list_for_each_entry_safe(priv, t, &governor_list, entry) {
if (priv->gov == gov) {
list_del(&priv->entry);
kfree(priv);
break;
}
}
spin_lock_irq(&pretimeout_lock);
list_for_each_entry(p, &pretimeout_list, entry)
if (p->wdd->gov == gov)
p->wdd->gov = default_gov;
spin_unlock_irq(&pretimeout_lock);
mutex_unlock(&governor_lock);
}
EXPORT_SYMBOL(watchdog_unregister_governor);
int watchdog_register_pretimeout(struct watchdog_device *wdd)
{
struct watchdog_pretimeout *p;
if (!(wdd->info->options & WDIOF_PRETIMEOUT))
return 0;
p = kzalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return -ENOMEM;
spin_lock_irq(&pretimeout_lock);
list_add(&p->entry, &pretimeout_list);
p->wdd = wdd;
wdd->gov = default_gov;
spin_unlock_irq(&pretimeout_lock);
return 0;
}
void watchdog_unregister_pretimeout(struct watchdog_device *wdd)
{
struct watchdog_pretimeout *p, *t;
if (!(wdd->info->options & WDIOF_PRETIMEOUT))
return;
spin_lock_irq(&pretimeout_lock);
wdd->gov = NULL;
list_for_each_entry_safe(p, t, &pretimeout_list, entry) {
if (p->wdd == wdd) {
list_del(&p->entry);
break;
}
}
spin_unlock_irq(&pretimeout_lock);
kfree(p);
}