Re: [PATCH v2 7/7] gpiolib: use bitmap_zalloc() for fastpath bitmaps

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] gpiolib: define and initialize __free() variable in gpio_descs_alloc()
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commit 014858138dec2ff00e5cb0fd3fa050587447ef44
Author: Dmitry Torokhov <dmitry.torokhov@gmail.com>

gpiolib: use bitmap_zalloc() for fastpath bitmaps

This commit converts invert_mask in struct gpio_array to a pointer and
allocates the get_mask, set_mask, and invert_mask fastpath bitmaps
individually via bitmap_zalloc() instead of a single combined kzalloc()
with manual pointer arithmetic.

> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index cf311c1a707c9..bba4e5bb125f9 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -5208,13 +5208,28 @@ static void gpiochip_free_hogs(struct gpio_chip *gc)

[ ... ]

> +static struct gpio_descs *gpio_descs_alloc(unsigned int count,
> +					   struct gpio_desc *first_desc)
>  {
>  	struct gpio_device *gdev = gpiod_to_gpio_device(first_desc);
> +	struct gpio_descs *descs __free(gpiod_put_array) = NULL;
>  	struct gpio_array *array_info;
> -	struct gpio_descs *descs;
>  	size_t descs_size, alloc_size;
> -	unsigned int bitmap_size;
> +	unsigned int nbits;
>  
>  	/*
>  	 * If pin hardware number of array member 0 is also 0, select
> @@ -5224,25 +5239,36 @@ static struct gpio_descs *gpio_descs_alloc(unsigned int count, struct gpio_desc
>  		return kzalloc_flex(*descs, desc, count);
>  
>  	descs_size = struct_size(descs, desc, count);
> -	bitmap_size = BITS_TO_LONGS(max(gdev->ngpio, count));
> -	alloc_size = descs_size + struct_size(array_info, invert_mask, 3 * bitmap_size);
> +	alloc_size = descs_size + sizeof(*array_info);
>  
>  	descs = kzalloc(alloc_size, GFP_KERNEL);

[Severity: Low]
This isn't a bug, but cleanup.h conventions prefer defining and initializing
__free() variables in a single statement rather than declaring them as NULL
at the top of the function and assigning them later.

In gpio_descs_alloc(), could descs be defined and initialized directly at the
kzalloc() call site after computing descs_size (using struct_size_t(struct
gpio_descs, desc, count)) and alloc_size?

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Sashiko AI review · https://sashiko.dev/#/patchset/20261103-b4-gpiolib-free-v2-0-ea46767c9cf8@gmail.com?part=7