2011-05-03 21:54:15

by Thiago Farina

Subject: regulators: kzalloc doubt

Hi guys,

What is the preferred way to use kzalloc? I have seen two ways under
drivers/regulator/.

1-

struct my_regulator_info *info = NULL;

info = kzalloc(sizeof(struct my_regulator_info), GFP_KERNEL);

2-

struct my_regulator_info *info;

info = kzalloc(sizeof(*info), GFP_KERNEL);

2011-05-03 21:58:32

by Hagen Paul Pfeifer

Subject: Re: regulators: kzalloc doubt

* Thiago Farina | 2011-05-03 18:54:13 [-0300]:

>What is the preferred way to use kzalloc? I have seen two ways under
>drivers/regulator/.
>
>1-
>
>struct my_regulator_info *info = NULL;
>
>info = kzalloc(sizeof(struct my_regulator_info), GFP_KERNEL);
>
>2-
>
>struct my_regulator_info *info;
>
>info = kzalloc(sizeof(*info), GFP_KERNEL);

Documentation/CodingStyle - Chapter 14: Allocating memory:


[...]
The preferred form for passing a size of a struct is the following:

p = kmalloc(sizeof(*p), ...);

The alternative form where struct name is spelled out hurts readability and
introduces an opportunity for a bug when the pointer variable type is changed
but the corresponding sizeof that is passed to a memory allocator is not.

Casting the return value which is a void pointer is redundant. The conversion
from void pointer to any other pointer type is guaranteed by the C programming
language.


Cheers, Hagen