cpumask: Remove unnecessary cpumask_nth_andnot()

JIRA: https://issues.redhat.com/browse/RHEL-122044

commit b0c85e9
Author: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Date:   Mon Jun 23 16:46:45 2025 +0900

    cpumask: Remove unnecessary cpumask_nth_andnot()

    Commit 94f7531("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@jp.fujitsu.com>
    Signed-off-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>

Signed-off-by: Steve Best <sbest@redhat.com>

Author: sfbest

include/linux/cpumask.h

@@ -529,22 +529,6 @@ 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

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