linux-kernel - Re: [PATCH v2] cpumask: Remove unnecessary cpumask_nth

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Message-ID: <aFl-VCOMa7N6AtmF@yury>
Date: Mon, 23 Jun 2025 12:18:28 -0400
From: Yury Norov <yury.norov@...il.com>
To: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
Cc: linux-kernel@...r.kernel.org,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Reinette Chatre <reinette.chatre@...el.com>,
	James Morse <james.morse@....com>,
	Dave Martin <dave.martin@....com>, fenghuay@...dia.com
Subject: Re: [PATCH v2] cpumask: Remove unnecessary cpumask_nth_andnot()

On Mon, Jun 23, 2025 at 04:46:45PM +0900, Shaopeng Tan wrote:
> Commit 94f753143028("x86/resctrl: Optimize cpumask_any_housekeeping()")
> switched the only user of cpumask_nth_andnot() to other cpumask
> functions, but left the function cpumask_nth_andnot() unused.
> This makes function find_nth_andnot_bit() unused as well. Delete them.
> 
> Signed-off-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>

Applied in bitmap-for-next. Thanks!

> ---
>  include/linux/cpumask.h | 16 ----------------
>  include/linux/find.h    | 27 ---------------------------
>  2 files changed, 43 deletions(-)
> 
> diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
> index 7ae80a7ca81e..498790f74fa8 100644
> --- a/include/linux/cpumask.h
> +++ b/include/linux/cpumask.h
> @@ -546,22 +546,6 @@ unsigned int cpumask_nth_and(unsigned int cpu, const struct cpumask *srcp1,
>  				small_cpumask_bits, cpumask_check(cpu));
>  }
>  
> -/**
> - * cpumask_nth_andnot - get the Nth cpu set in 1st cpumask, and clear in 2nd.
> - * @srcp1: the cpumask pointer
> - * @srcp2: the cpumask pointer
> - * @cpu: the Nth cpu to find, starting from 0
> - *
> - * Return: >= nr_cpu_ids if such cpu doesn't exist.
> - */
> -static __always_inline
> -unsigned int cpumask_nth_andnot(unsigned int cpu, const struct cpumask *srcp1,
> -							const struct cpumask *srcp2)
> -{
> -	return find_nth_andnot_bit(cpumask_bits(srcp1), cpumask_bits(srcp2),
> -				small_cpumask_bits, cpumask_check(cpu));
> -}
> -
>  /**
>   * cpumask_nth_and_andnot - get the Nth cpu set in 1st and 2nd cpumask, and clear in 3rd.
>   * @srcp1: the cpumask pointer
> diff --git a/include/linux/find.h b/include/linux/find.h
> index 5a2c267ea7f9..dc93fc35dcac 100644
> --- a/include/linux/find.h
> +++ b/include/linux/find.h
> @@ -267,33 +267,6 @@ unsigned long find_nth_and_bit(const unsigned long *addr1, const unsigned long *
>  	return __find_nth_and_bit(addr1, addr2, size, n);
>  }
>  
> -/**
> - * find_nth_andnot_bit - find N'th set bit in 2 memory regions,
> - *			 flipping bits in 2nd region
> - * @addr1: The 1st address to start the search at
> - * @addr2: The 2nd address to start the search at
> - * @size: The maximum number of bits to search
> - * @n: The number of set bit, which position is needed, counting from 0
> - *
> - * Returns the bit number of the N'th set bit.
> - * If no such, returns @size.
> - */
> -static __always_inline
> -unsigned long find_nth_andnot_bit(const unsigned long *addr1, const unsigned long *addr2,
> -				unsigned long size, unsigned long n)
> -{
> -	if (n >= size)
> -		return size;
> -
> -	if (small_const_nbits(size)) {
> -		unsigned long val =  *addr1 & (~*addr2) & GENMASK(size - 1, 0);
> -
> -		return val ? fns(val, n) : size;
> -	}
> -
> -	return __find_nth_andnot_bit(addr1, addr2, size, n);
> -}
> -
>  /**
>   * find_nth_and_andnot_bit - find N'th set bit in 2 memory regions,
>   *			     excluding those set in 3rd region
> -- 
> 2.43.5