[PATCH] drivers: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO

[PATCH] drivers: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO

[Duan Jiong]

This patch fixes coccinelle error regarding usage of IS_ERR and
PTR_ERR instead of PTR_ERR_OR_ZERO.

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
---
 drivers/misc/carma/carma-fpga.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/misc/carma/carma-fpga.c b/drivers/misc/carma/carma-fpga.c
index 08b18f3..9a32e98 100644
--- a/drivers/misc/carma/carma-fpga.c
+++ b/drivers/misc/carma/carma-fpga.c
@@ -956,10 +956,7 @@ static int data_debugfs_init(struct fpga_device *priv)
 {
 	priv->dbg_entry = debugfs_create_file(drv_name, S_IRUGO, NULL, priv,
 					      &data_debug_fops);
-	if (IS_ERR(priv->dbg_entry))
-		return PTR_ERR(priv->dbg_entry);
-
-	return 0;
+	return PTR_ERR_OR_ZERO(priv->dbg_entry);
 }
 
 static void data_debugfs_exit(struct fpga_device *priv)
-- 
1.8.3.1

Re: [PATCH] drivers: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO

[Wei Yongjun]

On 11/01/2013 06:09 PM, Duan Jiong wrote:
> This patch fixes coccinelle error regarding usage of IS_ERR and
> PTR_ERR instead of PTR_ERR_OR_ZERO.
>
> Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
> ---
>  drivers/misc/carma/carma-fpga.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/misc/carma/carma-fpga.c b/drivers/misc/carma/carma-fpga.c
> index 08b18f3..9a32e98 100644
> --- a/drivers/misc/carma/carma-fpga.c
> +++ b/drivers/misc/carma/carma-fpga.c
> @@ -956,10 +956,7 @@ static int data_debugfs_init(struct fpga_device *priv)
>  {
>  	priv->dbg_entry = debugfs_create_file(drv_name, S_IRUGO, NULL, priv,
>  					      &data_debug_fops);
> -	if (IS_ERR(priv->dbg_entry))
> -		return PTR_ERR(priv->dbg_entry);
> -
> -	return 0;
> +	return PTR_ERR_OR_ZERO(priv->dbg_entry);
>  }

Those code has make sure that CONFIG_DEBUG_FS is enabled, so
debugfs_create_file() never return PTR_ERR(), only NULL will
be returned when error occurs.

Re: [PATCH] drivers: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO

[Duan Jiong]

于 2013年11月11日 15:43, Wei Yongjun 写道:
> On 11/01/2013 06:09 PM, Duan Jiong wrote:
>> This patch fixes coccinelle error regarding usage of IS_ERR and
>> PTR_ERR instead of PTR_ERR_OR_ZERO.
>>
>> Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
>> ---
>>  drivers/misc/carma/carma-fpga.c | 5 +----
>>  1 file changed, 1 insertion(+), 4 deletions(-)
>>
>> diff --git a/drivers/misc/carma/carma-fpga.c b/drivers/misc/carma/carma-fpga.c
>> index 08b18f3..9a32e98 100644
>> --- a/drivers/misc/carma/carma-fpga.c
>> +++ b/drivers/misc/carma/carma-fpga.c
>> @@ -956,10 +956,7 @@ static int data_debugfs_init(struct fpga_device *priv)
>>  {
>>  	priv->dbg_entry = debugfs_create_file(drv_name, S_IRUGO, NULL, priv,
>>  					      &data_debug_fops);
>> -	if (IS_ERR(priv->dbg_entry))
>> -		return PTR_ERR(priv->dbg_entry);
>> -
>> -	return 0;
>> +	return PTR_ERR_OR_ZERO(priv->dbg_entry);
>>  }
> 
> Those code has make sure that CONFIG_DEBUG_FS is enabled, so
> debugfs_create_file() never return PTR_ERR(), only NULL will
> be returned when error occurs.
> 
>

You can see the definition about PTR_ERR_OR_ZERO in include/linux/err.h,
it is merely used to simplify the code.

Thanks,
  Duan

Re: [PATCH] drivers: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO

[Wei Yongjun]

On 11/11/2013 04:38 PM, Duan Jiong wrote:
> 于 2013年11月11日 15:43, Wei Yongjun 写道:
>> On 11/01/2013 06:09 PM, Duan Jiong wrote:
>>> This patch fixes coccinelle error regarding usage of IS_ERR and
>>> PTR_ERR instead of PTR_ERR_OR_ZERO.
>>>
>>> Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
>>> ---
>>>  drivers/misc/carma/carma-fpga.c | 5 +----
>>>  1 file changed, 1 insertion(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/misc/carma/carma-fpga.c b/drivers/misc/carma/carma-fpga.c
>>> index 08b18f3..9a32e98 100644
>>> --- a/drivers/misc/carma/carma-fpga.c
>>> +++ b/drivers/misc/carma/carma-fpga.c
>>> @@ -956,10 +956,7 @@ static int data_debugfs_init(struct fpga_device *priv)
>>>  {
>>>  	priv->dbg_entry = debugfs_create_file(drv_name, S_IRUGO, NULL, priv,
>>>  					      &data_debug_fops);
>>> -	if (IS_ERR(priv->dbg_entry))
>>> -		return PTR_ERR(priv->dbg_entry);
>>> -
>>> -	return 0;
>>> +	return PTR_ERR_OR_ZERO(priv->dbg_entry);
>>>  }
>> Those code has make sure that CONFIG_DEBUG_FS is enabled, so
>> debugfs_create_file() never return PTR_ERR(), only NULL will
>> be returned when error occurs.
>>
>>
> You can see the definition about PTR_ERR_OR_ZERO in include/linux/err.h,
> it is merely used to simplify the code.

I means that the orig code has bug. You should fix the bug, not only do
some cleanup like this.

Also, the module name should be 'carma-fpga', not 'drivers'. You should send
something like this:

[PATCH] carma-fpga: fix the return value check in data_debugfs_init()

In case of error, the function debugfs_create_file() returns NULL
pointer not ERR_PTR() if CONFIG_DEBUG_FS is enabled. The IS_ERR()
test in the return value check should be replaced with NULL test.

...

-       if (IS_ERR(priv->dbg_entry))
-               return PTR_ERR(priv->dbg_entry);
+       if (!priv->dbg_entry)
+               return -ENOMEM;
...