2024-03-28 12:14:49

by Shahar Avidar

Subject: [PATCH 5/5] staging: pi433: Remove duplicated code using the "goto" error recovery scheme.

pi433_init had "unregister_chrdev" called twice.
Remove it using goto statements.

Signed-off-by: Shahar Avidar <[email protected]>
---
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;

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);
+unreg_chrdev:
+ unregister_chrdev(MAJOR(pi433_devt), pi433_spi_driver.driver.name);
+fail:
return status;
}

--
2.34.1

2024-03-28 14:14:50

by Dan Carpenter

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

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 <[email protected]>
> ---
> 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.

>
> 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/

regards,
dan carpenter

> +unreg_chrdev:
> + unregister_chrdev(MAJOR(pi433_devt), pi433_spi_driver.driver.name);
> +fail:
> return status;
> }

2024-04-02 11:20:13

by Shahar Avidar

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 <[email protected]>
>> ---
>> 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