Xen devel - Mar 2012 - [PATCH] watchdog/xen: don't clear is_active when xen_wdt_stop() failed

xen_wdt_release() shouldn''t clear is_active even when the watchdog
didn''t get stopped (which by itself shouldn''t happen, but
let''s return
a proper error in this case rather than adding a BUG() upon hypercall
failure).

Signed-off-by: Jan Beulich <jbeulich@suse.com>

---
 drivers/watchdog/xen_wdt.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- 3.3/drivers/watchdog/xen_wdt.c
+++ 3.3-xen-watchdog-release/drivers/watchdog/xen_wdt.c
@@ -131,16 +131,18 @@ static int xen_wdt_open(struct inode *in
 
 static int xen_wdt_release(struct inode *inode, struct file *file)
 {
+	int err = 0;
+
 	if (expect_release)
-		xen_wdt_stop();
+		err = xen_wdt_stop();
 	else {
 		printk(KERN_CRIT PFX
 		       "unexpected close, not stopping watchdog!\n");
 		xen_wdt_kick();
 	}
-	is_active = false;
+	is_active = err;
 	expect_release = false;
-	return 0;
+	return err;
 }
 
 static ssize_t xen_wdt_write(struct file *file, const char __user *data,

On Mon, Mar 19, 2012 at 09:32:28AM +0000, Jan Beulich
wrote:
> xen_wdt_release() shouldn''t clear is_active even when the watchdog
> didn''t get stopped (which by itself shouldn''t happen, but
let''s return
> a proper error in this case rather than adding a BUG() upon hypercall
> failure).
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Looks good to me too. Wim, want me to carry it for 3.4?
> 
> ---
>  drivers/watchdog/xen_wdt.c |    8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> --- 3.3/drivers/watchdog/xen_wdt.c
> +++ 3.3-xen-watchdog-release/drivers/watchdog/xen_wdt.c
> @@ -131,16 +131,18 @@ static int xen_wdt_open(struct inode *in
>  
>  static int xen_wdt_release(struct inode *inode, struct file *file)
>  {
> +	int err = 0;
> +
>  	if (expect_release)
> -		xen_wdt_stop();
> +		err = xen_wdt_stop();
>  	else {
>  		printk(KERN_CRIT PFX
>  		       "unexpected close, not stopping watchdog!\n");
>  		xen_wdt_kick();
>  	}
> -	is_active = false;
> +	is_active = err;
>  	expect_release = false;
> -	return 0;
> +	return err;
>  }
>  
>  static ssize_t xen_wdt_write(struct file *file, const char __user *data,
> 
>

Hi Jan,
> xen_wdt_release() shouldn''t clear is_active even when the watchdog
> didn''t get stopped (which by itself shouldn''t happen, but
let''s return
> a proper error in this case rather than adding a BUG() upon hypercall
> failure).
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 
> ---
>  drivers/watchdog/xen_wdt.c |    8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> --- 3.3/drivers/watchdog/xen_wdt.c
> +++ 3.3-xen-watchdog-release/drivers/watchdog/xen_wdt.c
> @@ -131,16 +131,18 @@ static int xen_wdt_open(struct inode *in
>  
>  static int xen_wdt_release(struct inode *inode, struct file *file)
>  {
> +	int err = 0;
> +
>  	if (expect_release)
> -		xen_wdt_stop();
> +		err = xen_wdt_stop();
>  	else {
>  		printk(KERN_CRIT PFX
>  		       "unexpected close, not stopping watchdog!\n");
>  		xen_wdt_kick();
>  	}
> -	is_active = false;
> +	is_active = err;
>  	expect_release = false;
> -	return 0;
> +	return err;
>  }
>  
>  static ssize_t xen_wdt_write(struct file *file, const char __user *data,
Just for my understanding:
is_active is a bool value and err is an integer. What values are returned by
xen_wdt_stop?

Kind regards,
Wim.

>>> On 21.03.12 at 20:50, Wim Van Sebroeck <wim@iguana.be> wrote:
> Hi Jan,
> 
>> xen_wdt_release() shouldn''t clear is_active even when the
watchdog
>> didn''t get stopped (which by itself shouldn''t happen,
but let''s return
>> a proper error in this case rather than adding a BUG() upon hypercall
>> failure).
>> 
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>> 
>> ---
>>  drivers/watchdog/xen_wdt.c |    8 +++++---
>>  1 file changed, 5 insertions(+), 3 deletions(-)
>> 
>> --- 3.3/drivers/watchdog/xen_wdt.c
>> +++ 3.3-xen-watchdog-release/drivers/watchdog/xen_wdt.c
>> @@ -131,16 +131,18 @@ static int xen_wdt_open(struct inode *in
>>  
>>  static int xen_wdt_release(struct inode *inode, struct file *file)
>>  {
>> +	int err = 0;
>> +
>>  	if (expect_release)
>> -		xen_wdt_stop();
>> +		err = xen_wdt_stop();
>>  	else {
>>  		printk(KERN_CRIT PFX
>>  		       "unexpected close, not stopping watchdog!\n");
>>  		xen_wdt_kick();
>>  	}
>> -	is_active = false;
>> +	is_active = err;
>>  	expect_release = false;
>> -	return 0;
>> +	return err;
>>  }
>>  
>>  static ssize_t xen_wdt_write(struct file *file, const char __user
*data,
> 
> Just for my understanding:
> is_active is a bool value and err is an integer. What values are returned
by
> xen_wdt_stop?
xen_wdt_stop() returns the usual -errno values. Assignments from
non-bool to bool convert the value (non-zero -> true, zero -> false),
i.e. is_active gets set to false only if xen_wdt_stop() succeeded.

Jan