[PATCH] Mark res_counter_charge(_locked) with __must_check

[PATCH] Mark res_counter_charge(_locked) with __must_check

[Pavel Emelyanov]

Ignoring theirs return value may result in counter underflow
in the future - when the value charged will be uncharged (or in
"leaks" - when the value is not uncharged).

This also prevents from using charging routines to decrement the
counter value (i.e. uncharge it) ;)

(Current code works OK with res_counter, however :) )

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

---

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index 6d9e1fc..125660e 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -95,8 +95,10 @@ void res_counter_init(struct res_counter *counter);
  * counter->limit _locked call expects the counter->lock to be taken
  */
 
-int res_counter_charge_locked(struct res_counter *counter, unsigned long val);
-int res_counter_charge(struct res_counter *counter, unsigned long val);
+int __must_check res_counter_charge_locked(struct res_counter *counter,
+		unsigned long val);
+int __must_check res_counter_charge(struct res_counter *counter,
+		unsigned long val);
 
 /*
  * uncharge - tell that some portion of the resource is released

Re: [PATCH] Mark res_counter_charge(_locked) with __must_check

[KAMEZAWA Hiroyuki]

On Thu, 08 May 2008 13:05:44 +0400
Pavel Emelyanov <xemul@openvz.org> wrote:

> Ignoring theirs return value may result in counter underflow
> in the future - when the value charged will be uncharged (or in
> "leaks" - when the value is not uncharged).
> 
> This also prevents from using charging routines to decrement the
> counter value (i.e. uncharge it) ;)
> 
> (Current code works OK with res_counter, however :) )
> 
> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
> 
nice check :)

BTW, res_counter_charge_locked() should be extern function ?

Thanks,
-Kame

Re: [PATCH] Mark res_counter_charge(_locked) with __must_check

[Pavel Emelyanov]

KAMEZAWA Hiroyuki wrote:
> On Thu, 08 May 2008 13:05:44 +0400
> Pavel Emelyanov <xemul@openvz.org> wrote:
> 
>> Ignoring theirs return value may result in counter underflow
>> in the future - when the value charged will be uncharged (or in
>> "leaks" - when the value is not uncharged).
>>
>> This also prevents from using charging routines to decrement the
>> counter value (i.e. uncharge it) ;)
>>
>> (Current code works OK with res_counter, however :) )
>>
>> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
>>
> nice check :)

Thanks!

> BTW, res_counter_charge_locked() should be extern function ?

What do you mean? It is extern as well as the res_counter_charge
and uncharge ones are, but functions may have forward declarations
w/o extern keyword AFAIK ;)

> Thanks,
> -Kame
> 
> 

Re: [PATCH] Mark res_counter_charge(_locked) with __must_check

[KAMEZAWA Hiroyuki]

On Thu, 08 May 2008 13:40:53 +0400
Pavel Emelyanov <xemul@openvz.org> wrote:

> > BTW, res_counter_charge_locked() should be extern function ?
> 
> What do you mean? It is extern as well as the res_counter_charge
> and uncharge ones are, but functions may have forward declarations
> w/o extern keyword AFAIK ;)
>
Ah, 
Is  res_counter_charge_locked() is called from files other than res_counter.c ?
Does we need declaration in header file ?

Thanks,
-Kame

Re: [PATCH] Mark res_counter_charge(_locked) with __must_check

[Pavel Emelyanov]

KAMEZAWA Hiroyuki wrote:
> On Thu, 08 May 2008 13:40:53 +0400
> Pavel Emelyanov <xemul@openvz.org> wrote:
> 
>>> BTW, res_counter_charge_locked() should be extern function ?
>> What do you mean? It is extern as well as the res_counter_charge
>> and uncharge ones are, but functions may have forward declarations
>> w/o extern keyword AFAIK ;)
>>
> Ah, 
> Is  res_counter_charge_locked() is called from files other than res_counter.c ?

I checked - everything was OK.

> Does we need declaration in header file ?

But this patch _is_ for declaration in header :)

> Thanks,
> -Kame
> 
>