linux-kernel - Re: [PATCH v1 1/1] bitmap: Remove dead code, i.e. bitmap_copy

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Message-ID: <ZO0gh2aj9Nrr/jIC@yury-ThinkPad>
Date:   Mon, 28 Aug 2023 18:18:35 -0700
From:   Yury Norov <yury.norov@...il.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org,
        Rasmus Villemoes <linux@...musvillemoes.dk>
Subject: Re: [PATCH v1 1/1] bitmap: Remove dead code, i.e. bitmap_copy_le()

On Thu, Aug 17, 2023 at 07:20:54PM +0300, Andy Shevchenko wrote:
> Besides the fact it's not used anywhere it should be implemented
> differently, i.e. via helpers from linux/byteorder/generic.h.
> Yet the helpers themselves need to be introduced first.
> 
> Also note, the function lacks of the test cases, they must be provided.
> 
> Hence, drop the current dead code for good.
 
It was added in 2008 for UWB subsystem, removed in 2019 by Greg with a note
that UWB an obsolete; and bitmap_copy_le() looks like a leftover. So I think
you're right, it's worth to drop it.

I'll add the patch in the next pull request.

Thanks,
Yury

> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>  include/linux/bitmap.h |  5 -----
>  lib/bitmap.c           | 23 -----------------------
>  2 files changed, 28 deletions(-)
> 
> diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
> index 03644237e1ef..1516ff979315 100644
> --- a/include/linux/bitmap.h
> +++ b/include/linux/bitmap.h
> @@ -220,11 +220,6 @@ int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
>  void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order);
>  int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order);
>  
> -#ifdef __BIG_ENDIAN
> -void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits);
> -#else
> -#define bitmap_copy_le bitmap_copy
> -#endif
>  int bitmap_print_to_pagebuf(bool list, char *buf,
>  				   const unsigned long *maskp, int nmaskbits);
>  
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 24284caadbcc..935e0f96e785 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -1360,29 +1360,6 @@ int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
>  }
>  EXPORT_SYMBOL(bitmap_allocate_region);
>  
> -/**
> - * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
> - * @dst:   destination buffer
> - * @src:   bitmap to copy
> - * @nbits: number of bits in the bitmap
> - *
> - * Require nbits % BITS_PER_LONG == 0.
> - */
> -#ifdef __BIG_ENDIAN
> -void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits)
> -{
> -	unsigned int i;
> -
> -	for (i = 0; i < nbits/BITS_PER_LONG; i++) {
> -		if (BITS_PER_LONG == 64)
> -			dst[i] = cpu_to_le64(src[i]);
> -		else
> -			dst[i] = cpu_to_le32(src[i]);
> -	}
> -}
> -EXPORT_SYMBOL(bitmap_copy_le);
> -#endif
> -
>  unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
>  {
>  	return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
> -- 
> 2.40.0.1.gaa8946217a0b