[PATCH] rtc: avoid calling platform_device_put() twice in test_init()

[PATCH] rtc: avoid calling platform_device_put() twice in test_init()

[Wei Yongjun]

From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>

In case of error, the function test_init() need to call
platform_device_del() instead of platform_device_unregister().
Otherwise, we may call platform_device_put() twice.

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
---
 drivers/rtc/rtc-test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-test.c b/drivers/rtc/rtc-test.c
index 7e96254..209a127 100644
--- a/drivers/rtc/rtc-test.c
+++ b/drivers/rtc/rtc-test.c
@@ -164,7 +164,7 @@ static int __init test_init(void)
 	return 0;
 
 exit_device_unregister:
-	platform_device_unregister(test0);
+	platform_device_del(test0);
 
 exit_free_test1:
 	platform_device_put(test1);

Re: [PATCH] rtc: avoid calling platform_device_put() twice in test_init()

[Andrew Morton]

On Tue, 23 Oct 2012 13:08:41 +0800
Wei Yongjun <weiyj.lk@gmail.com> wrote:

> From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> 
> In case of error, the function test_init() need to call
> platform_device_del() instead of platform_device_unregister().
> Otherwise, we may call platform_device_put() twice.
> 
> dpatch engine is used to auto generate this patch.
> (https://github.com/weiyj/dpatch)
> 
> Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> ---
>  drivers/rtc/rtc-test.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/rtc/rtc-test.c b/drivers/rtc/rtc-test.c
> index 7e96254..209a127 100644
> --- a/drivers/rtc/rtc-test.c
> +++ b/drivers/rtc/rtc-test.c
> @@ -164,7 +164,7 @@ static int __init test_init(void)
>  	return 0;
>  
>  exit_device_unregister:
> -	platform_device_unregister(test0);
> +	platform_device_del(test0);
>  
>  exit_free_test1:
>  	platform_device_put(test1);

Is platform_device_del() the partner to platform_device_add()?  If so
then yes, this looks right.  But I think the labels can be improved:

--- a/drivers/rtc/rtc-test.c~rtc-avoid-calling-platform_device_put-twice-in-test_init-fix
+++ a/drivers/rtc/rtc-test.c
@@ -152,24 +152,24 @@ static int __init test_init(void)
 
 	if ((test1 = platform_device_alloc("rtc-test", 1)) == NULL) {
 		err = -ENOMEM;
-		goto exit_free_test0;
+		goto exit_put_test0;
 	}
 
 	if ((err = platform_device_add(test0)))
-		goto exit_free_test1;
+		goto exit_put_test1;
 
 	if ((err = platform_device_add(test1)))
-		goto exit_device_unregister;
+		goto exit_del_test0;
 
 	return 0;
 
-exit_device_unregister:
+exit_del_test0:
 	platform_device_del(test0);
 
-exit_free_test1:
+exit_put_test1:
 	platform_device_put(test1);
 
-exit_free_test0:
+exit_put_test0:
 	platform_device_put(test0);
 
 exit_driver_unregister:
_


However, take a look at test_exit().  it does
platform_device_unregister(test0) when test0 is in the same state.  Is
that code wrong as well?  Presumably it's working OK?

Re: [PATCH] rtc: avoid calling platform_device_put() twice in test_init()

[Wei Yongjun]

On 11/07/2012 08:51 AM, Andrew Morton wrote:
> On Tue, 23 Oct 2012 13:08:41 +0800
> Wei Yongjun <weiyj.lk@gmail.com> wrote:
>
>> From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
>>
>> In case of error, the function test_init() need to call
>> platform_device_del() instead of platform_device_unregister().
>> Otherwise, we may call platform_device_put() twice.
>>
> Is platform_device_del() the partner to platform_device_add()?  If so
> then yes, this looks right.  But I think the labels can be improved:
>
> _
>
>
> However, take a look at test_exit().  it does
> platform_device_unregister(test0) when test0 is in the same state.  Is
> that code wrong as well?  Presumably it's working OK?

platform_device_unregister() is a warp of platform_device_del()
and platform_device_put(), if platform_device_add() success, we
can use platform_device_unregister() to do this, so that code
is OK.