linux-kernel - Re: [PATCH 2/5] watchdog: diag288

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Date:   Fri, 3 Feb 2023 10:23:30 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Alexander Egorenkov <egorenar@...ux.ibm.com>,
        wim@...ux-watchdog.org
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
        hca@...ux.ibm.com
Subject: Re: [PATCH 2/5] watchdog: diag288_wdt: remove power management

On 2/2/23 23:39, Alexander Egorenkov wrote:
> Remove power management because s390 no longer supports hibernation since
> commit 394216275c7d ("s390: remove broken hibernate / power management
> support").
> 
> Reviewed-by: Heiko Carstens <hca@...ux.ibm.com>
> Signed-off-by: Alexander Egorenkov <egorenar@...ux.ibm.com>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>   drivers/watchdog/diag288_wdt.c | 65 ++--------------------------------
>   1 file changed, 2 insertions(+), 63 deletions(-)
> 
> diff --git a/drivers/watchdog/diag288_wdt.c b/drivers/watchdog/diag288_wdt.c
> index 07ebbb709af4..c8d516ced6d2 100644
> --- a/drivers/watchdog/diag288_wdt.c
> +++ b/drivers/watchdog/diag288_wdt.c
> @@ -27,7 +27,6 @@
>   #include <linux/moduleparam.h>
>   #include <linux/slab.h>
>   #include <linux/watchdog.h>
> -#include <linux/suspend.h>
>   #include <asm/ebcdic.h>
>   #include <asm/diag.h>
>   #include <linux/io.h>
> @@ -103,10 +102,6 @@ static int __diag288_lpar(unsigned int func, unsigned int timeout,
>   	return __diag288(func, timeout, action, 0);
>   }
>   
> -static unsigned long wdt_status;
> -
> -#define DIAG_WDOG_BUSY	0
> -
>   static int wdt_start(struct watchdog_device *dev)
>   {
>   	char *ebc_cmd;
> @@ -114,15 +109,10 @@ static int wdt_start(struct watchdog_device *dev)
>   	int ret;
>   	unsigned int func;
>   
> -	if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status))
> -		return -EBUSY;
> -
>   	if (MACHINE_IS_VM) {
>   		ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
> -		if (!ebc_cmd) {
> -			clear_bit(DIAG_WDOG_BUSY, &wdt_status);
> +		if (!ebc_cmd)
>   			return -ENOMEM;
> -		}
>   		len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
>   		ASCEBC(ebc_cmd, MAX_CMDLEN);
>   		EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
> @@ -139,7 +129,6 @@ static int wdt_start(struct watchdog_device *dev)
>   
>   	if (ret) {
>   		pr_err("The watchdog cannot be activated\n");
> -		clear_bit(DIAG_WDOG_BUSY, &wdt_status);
>   		return ret;
>   	}
>   	return 0;
> @@ -152,8 +141,6 @@ static int wdt_stop(struct watchdog_device *dev)
>   	diag_stat_inc(DIAG_STAT_X288);
>   	ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
>   
> -	clear_bit(DIAG_WDOG_BUSY, &wdt_status);
> -
>   	return ret;
>   }
>   
> @@ -222,45 +209,6 @@ static struct watchdog_device wdt_dev = {
>   	.max_timeout = MAX_INTERVAL,
>   };
>   
> -/*
> - * It makes no sense to go into suspend while the watchdog is running.
> - * Depending on the memory size, the watchdog might trigger, while we
> - * are still saving the memory.
> - */
> -static int wdt_suspend(void)
> -{
> -	if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status)) {
> -		pr_err("Linux cannot be suspended while the watchdog is in use\n");
> -		return notifier_from_errno(-EBUSY);
> -	}
> -	return NOTIFY_DONE;
> -}
> -
> -static int wdt_resume(void)
> -{
> -	clear_bit(DIAG_WDOG_BUSY, &wdt_status);
> -	return NOTIFY_DONE;
> -}
> -
> -static int wdt_power_event(struct notifier_block *this, unsigned long event,
> -			   void *ptr)
> -{
> -	switch (event) {
> -	case PM_POST_HIBERNATION:
> -	case PM_POST_SUSPEND:
> -		return wdt_resume();
> -	case PM_HIBERNATION_PREPARE:
> -	case PM_SUSPEND_PREPARE:
> -		return wdt_suspend();
> -	default:
> -		return NOTIFY_DONE;
> -	}
> -}
> -
> -static struct notifier_block wdt_power_notifier = {
> -	.notifier_call = wdt_power_event,
> -};
> -
>   static int __init diag288_init(void)
>   {
>   	int ret;
> @@ -297,21 +245,12 @@ static int __init diag288_init(void)
>   		return -EINVAL;
>   	}
>   
> -	ret = register_pm_notifier(&wdt_power_notifier);
> -	if (ret)
> -		return ret;
> -
> -	ret = watchdog_register_device(&wdt_dev);
> -	if (ret)
> -		unregister_pm_notifier(&wdt_power_notifier);
> -
> -	return ret;
> +	return watchdog_register_device(&wdt_dev);
>   }
>   
>   static void __exit diag288_exit(void)
>   {
>   	watchdog_unregister_device(&wdt_dev);
> -	unregister_pm_notifier(&wdt_power_notifier);
>   }
>   
>   module_init(diag288_init);