linux-kernel - Re: [PATCH 5/5] staging: pi433: Remove duplicated code using the "goto" error recovery scheme.

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Date: Tue, 2 Apr 2024 14:19:18 +0300
From: Shahar Avidar <ikobh7@...il.com>
To: Dan Carpenter <dan.carpenter@...aro.org>
Cc: gregkh@...uxfoundation.org, hverkuil-cisco@...all.nl,
 andriy.shevchenko@...ux.intel.com, robh@...nel.org, felixkimbu1@...il.com,
 linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/5] staging: pi433: Remove duplicated code using the
 "goto" error recovery scheme.

Hi Dan, I appreciate your review.

On 28/03/2024 16:03, Dan Carpenter wrote:
> On Thu, Mar 28, 2024 at 02:12:44PM +0200, Shahar Avidar wrote:
>> pi433_init had "unregister_chrdev" called twice.
>> Remove it using goto statements.
>>
>> Signed-off-by: Shahar Avidar <ikobh7@...il.com>
>> ---
>>   drivers/staging/pi433/pi433_if.c | 23 ++++++++++++-----------
>>   1 file changed, 12 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c
>> index 62ce75b07bf0..e538f1d4e787 100644
>> --- a/drivers/staging/pi433/pi433_if.c
>> +++ b/drivers/staging/pi433/pi433_if.c
>> @@ -1400,24 +1400,25 @@ static int __init pi433_init(void)
>>   	 */
>>   	status = alloc_chrdev_region(&pi433_devt, 0, N_PI433_MINORS, "pi433");
>>   	if (status < 0)
>> -		return status;
>> +		goto fail;
> 
> Just return directly.  Do nothing gotos are bad for readability and they
> create Forgot to Set the Error Code bugs.  Also there was a direct
> return earlier in the function so it's better to do things consistently.
Fixed in V2.

> 
>>   
>>   	status = class_register(&pi433_class);
>> -	if (status) {
>> -		unregister_chrdev(MAJOR(pi433_devt),
>> -				  pi433_spi_driver.driver.name);
>> -		return status;
>> -	}
>> +	if (status)
>> +		goto unreg_chrdev;
>>   
>>   	root_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
>>   
>>   	status = spi_register_driver(&pi433_spi_driver);
>> -	if (status < 0) {
>> -		class_unregister(&pi433_class);
>> -		unregister_chrdev(MAJOR(pi433_devt),
>> -				  pi433_spi_driver.driver.name);
>> -	}
>> +	if (status < 0)
>> +		goto unreg_class;
>>   
>> +	return 0;
>> +
>> +unreg_class:
>> +	class_unregister(&pi433_class);
> 
> There is a debugfs_remove() missing.  I have written a blog that might
> be helpful:
> 
> https://staticthinking.wordpress.com/2022/04/28/free-the-last-thing-style/
Interesting blog post.
I hope I followed through & made the right changes.
> 
> regards,
> dan carpenter
> 
>> +unreg_chrdev:
>> +	unregister_chrdev(MAJOR(pi433_devt), pi433_spi_driver.driver.name);
>> +fail:
>>   	return status;
>>   }
> 
-- 
Regards,

Shahar