linux-kernel - Re: [PATCH 3/4] bitmap: Introduce bitmap

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Message-ID: <YsC0GpltMVaCPhkJ@yury-laptop>
Date:   Sat, 2 Jul 2022 14:09:46 -0700
From:   Yury Norov <yury.norov@...il.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     agk@...hat.com, snitzer@...nel.org, dm-devel@...hat.com,
        vneethv@...ux.ibm.com, oberpar@...ux.ibm.com, hca@...ux.ibm.com,
        gor@...ux.ibm.com, agordeev@...ux.ibm.com,
        borntraeger@...ux.ibm.com, svens@...ux.ibm.com,
        almaz.alexandrovich@...agon-software.com,
        andriy.shevchenko@...ux.intel.com, linux@...musvillemoes.dk,
        linux-s390@...r.kernel.org, ntfs3@...ts.linux.dev,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH 3/4] bitmap: Introduce bitmap_size()

On Sat, Jul 02, 2022 at 08:29:36PM +0200, Christophe JAILLET wrote:
> The new bitmap_size() function returns the size, in bytes, of a bitmap.
> 
> Remove the already existing bitmap_size() functions and macro in some
> files.
> These files already use the bitmap API and will use the new function
> in bitmap.h automatically.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> ---
>  drivers/md/dm-clone-metadata.c | 5 -----
>  include/linux/bitmap.h         | 6 ++++++
>  lib/math/prime_numbers.c       | 2 --
>  3 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/md/dm-clone-metadata.c b/drivers/md/dm-clone-metadata.c
> index c43d55672bce..47c1fa7aad8b 100644
> --- a/drivers/md/dm-clone-metadata.c
> +++ b/drivers/md/dm-clone-metadata.c
> @@ -465,11 +465,6 @@ static void __destroy_persistent_data_structures(struct dm_clone_metadata *cmd)
>  
>  /*---------------------------------------------------------------------------*/
>  
> -static size_t bitmap_size(unsigned long nr_bits)
> -{
> -	return BITS_TO_LONGS(nr_bits) * sizeof(long);
> -}
> -
>  static int __dirty_map_init(struct dirty_map *dmap, unsigned long nr_words,
>  			    unsigned long nr_regions)
>  {
> diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
> index f091a1664bf1..f66fb98a4126 100644
> --- a/include/linux/bitmap.h
> +++ b/include/linux/bitmap.h
> @@ -48,6 +48,7 @@ struct device;
>   *  bitmap_equal(src1, src2, nbits)             Are *src1 and *src2 equal?
>   *  bitmap_intersects(src1, src2, nbits)        Do *src1 and *src2 overlap?
>   *  bitmap_subset(src1, src2, nbits)            Is *src1 a subset of *src2?
> + *  bitmap_size(nbits)                          Size, in bytes, of a bitmap
>   *  bitmap_empty(src, nbits)                    Are all bits zero in *src?
>   *  bitmap_full(src, nbits)                     Are all bits set in *src?
>   *  bitmap_weight(src, nbits)                   Hamming Weight: number set bits
> @@ -124,6 +125,11 @@ unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node);
>  unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node);
>  void bitmap_free(const unsigned long *bitmap);
>  
> +static __always_inline size_t bitmap_size(unsigned long nbits)
> +{
> +	return BITS_TO_LONGS(nbits) * sizeof(unsigned long);
> +}
> +
>  /* Managed variants of the above. */
>  unsigned long *devm_bitmap_alloc(struct device *dev,
>  				 unsigned int nbits, gfp_t flags);
> diff --git a/lib/math/prime_numbers.c b/lib/math/prime_numbers.c
> index d42cebf7407f..d3b64b10da1c 100644
> --- a/lib/math/prime_numbers.c
> +++ b/lib/math/prime_numbers.c
> @@ -6,8 +6,6 @@
>  #include <linux/prime_numbers.h>
>  #include <linux/slab.h>
>  
> -#define bitmap_size(nbits) (BITS_TO_LONGS(nbits) * sizeof(unsigned long))
> -

This should be dropped, for sure, and kmalloc() at line 128 should be
replaced with bitmap_alloc().

For the driver, we need to introduce bitmap_kvmalloc/bitmap_kvfree etc. 

>  struct primes {
>  	struct rcu_head rcu;
>  	unsigned long last, sz;
> -- 
> 2.34.1