Commit cdc66553 authored by Dawei Li's avatar Dawei Li Committed by Thomas Gleixner
Browse files

cpumask: Introduce cpumask_first_and_and() 



Introduce cpumask_first_and_and() to get intersection between 3 cpumasks,
free of any intermediate cpumask variable. Instead, cpumask_first_and_and()
works in-place with all inputs and produces desired output directly.

Signed-off-by: default avatarDawei Li <dawei.li@shingroup.cn>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarYury Norov <yury.norov@gmail.com>
Link: https://lore.kernel.org/r/20240416085454.3547175-2-dawei.li@shingroup.cn
parent c7cad38d

include/linux/cpumask.h

+17 −0
Original line number Diff line number Diff line
@@ -187,6 +187,23 @@ unsigned int cpumask_first_and(const struct cpumask *srcp1, const struct cpumask 
	return find_first_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits);

}



/**

 * cpumask_first_and_and - return the first cpu from *srcp1 & *srcp2 & *srcp3

 * @srcp1: the first input

 * @srcp2: the second input

 * @srcp3: the third input

 *

 * Return: >= nr_cpu_ids if no cpus set in all.

 */

static inline

unsigned int cpumask_first_and_and(const struct cpumask *srcp1,

				   const struct cpumask *srcp2,

				   const struct cpumask *srcp3)

{

	return find_first_and_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2),

				      cpumask_bits(srcp3), small_cpumask_bits);

}



/**

 * cpumask_last - get the last CPU in a cpumask

 * @srcp:	- the cpumask pointer

include/linux/find.h

+27 −0
Original line number Diff line number Diff line
@@ -29,6 +29,8 @@ unsigned long __find_nth_and_andnot_bit(const unsigned long *addr1, const unsign 
					unsigned long n);

extern unsigned long _find_first_and_bit(const unsigned long *addr1,

					 const unsigned long *addr2, unsigned long size);

unsigned long _find_first_and_and_bit(const unsigned long *addr1, const unsigned long *addr2,

				      const unsigned long *addr3, unsigned long size);

extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size);

extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long size);
@@ -345,6 +347,31 @@ unsigned long find_first_and_bit(const unsigned long *addr1, 
}

#endif



/**

 * find_first_and_and_bit - find the first set bit in 3 memory regions

 * @addr1: The first address to base the search on

 * @addr2: The second address to base the search on

 * @addr3: The third address to base the search on

 * @size: The bitmap size in bits

 *

 * Returns the bit number for the first set bit

 * If no bits are set, returns @size.

 */

static inline

unsigned long find_first_and_and_bit(const unsigned long *addr1,

				     const unsigned long *addr2,

				     const unsigned long *addr3,

				     unsigned long size)

{

	if (small_const_nbits(size)) {

		unsigned long val = *addr1 & *addr2 & *addr3 & GENMASK(size - 1, 0);



		return val ? __ffs(val) : size;

	}



	return _find_first_and_and_bit(addr1, addr2, addr3, size);

}



#ifndef find_first_zero_bit

/**

 * find_first_zero_bit - find the first cleared bit in a memory region

lib/find_bit.c

+12 −0
Original line number Diff line number Diff line
@@ -116,6 +116,18 @@ unsigned long _find_first_and_bit(const unsigned long *addr1, 
EXPORT_SYMBOL(_find_first_and_bit);

#endif



/*

 * Find the first set bit in three memory regions.

 */

unsigned long _find_first_and_and_bit(const unsigned long *addr1,

				      const unsigned long *addr2,

				      const unsigned long *addr3,

				      unsigned long size)

{

	return FIND_FIRST_BIT(addr1[idx] & addr2[idx] & addr3[idx], /* nop */, size);

}

EXPORT_SYMBOL(_find_first_and_and_bit);



#ifndef find_first_zero_bit

/*

 * Find the first cleared bit in a memory region.