// SPDX-License-Identifier: GPL-2.0#include <linux/slab.h>#include <linux/kernel.h>#include <linux/bitops.h>#include <linux/cpumask.h>#include <linux/export.h>#include <linux/memblock.h>#include <linux/numa.h>#include <linux/sched/isolation.h> /** * cpumask_next - get the next cpu in a cpumask * @n: the cpu prior to the place to search (ie. return will be > @n) * @srcp: the cpumask pointer * * Returns >= nr_cpu_ids if no further cpus set. */unsigned int cpumask_next(int n, const struct cpumask *srcp){	/* -1 is a legal arg here. */	if (n != -1)		cpumask_check(n);	return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n + 1);}EXPORT_SYMBOL(cpumask_next); /** * cpumask_next_and - get the next cpu in *src1p & *src2p * @n: the cpu prior to the place to search (ie. return will be > @n) * @src1p: the first cpumask pointer * @src2p: the second cpumask pointer * * Returns >= nr_cpu_ids if no further cpus set in both. */int cpumask_next_and(int n, const struct cpumask *src1p,		     const struct cpumask *src2p){	/* -1 is a legal arg here. */	if (n != -1)		cpumask_check(n);	return find_next_and_bit(cpumask_bits(src1p), cpumask_bits(src2p),		nr_cpumask_bits, n + 1);}EXPORT_SYMBOL(cpumask_next_and); /** * cpumask_any_but - return a "random" in a cpumask, but not this one. * @mask: the cpumask to search * @cpu: the cpu to ignore. * * Often used to find any cpu but smp_processor_id() in a mask. * Returns >= nr_cpu_ids if no cpus set. */int cpumask_any_but(const struct cpumask *mask, unsigned int cpu){	unsigned int i; 	cpumask_check(cpu);	for_each_cpu(i, mask)		if (i != cpu)			break;	return i;}EXPORT_SYMBOL(cpumask_any_but); /** * cpumask_next_wrap - helper to implement for_each_cpu_wrap * @n: the cpu prior to the place to search * @mask: the cpumask pointer * @start: the start point of the iteration * @wrap: assume @n crossing @start terminates the iteration * * Returns >= nr_cpu_ids on completion * * Note: the @wrap argument is required for the start condition when * we cannot assume @start is set in @mask. */int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap){	int next; again:	next = cpumask_next(n, mask); 	if (wrap && n < start && next >= start) {		return nr_cpumask_bits; 	} else if (next >= nr_cpumask_bits) {		wrap = true;		n = -1;		goto again;	} 	return next;}EXPORT_SYMBOL(cpumask_next_wrap); /* These are not inline because of header tangles. */#ifdef CONFIG_CPUMASK_OFFSTACK/** * alloc_cpumask_var_node - allocate a struct cpumask on a given node * @mask: pointer to cpumask_var_t where the cpumask is returned * @flags: GFP_ flags * * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is * a nop returning a constant 1 (in <linux/cpumask.h>) * Returns TRUE if memory allocation succeeded, FALSE otherwise. * * In addition, mask will be NULL if this fails.  Note that gcc is * usually smart enough to know that mask can never be NULL if * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case * too. */bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node){	*mask = kmalloc_node(cpumask_size(), flags, node); #ifdef CONFIG_DEBUG_PER_CPU_MAPS	if (!*mask) {		printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");		dump_stack();	}#endif 	return *mask != NULL;}EXPORT_SYMBOL(alloc_cpumask_var_node); bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node){	return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);}EXPORT_SYMBOL(zalloc_cpumask_var_node); /** * alloc_cpumask_var - allocate a struct cpumask * @mask: pointer to cpumask_var_t where the cpumask is returned * @flags: GFP_ flags * * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is * a nop returning a constant 1 (in <linux/cpumask.h>). * * See alloc_cpumask_var_node. */bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags){	return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE);}EXPORT_SYMBOL(alloc_cpumask_var); bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags){	return alloc_cpumask_var(mask, flags | __GFP_ZERO);}EXPORT_SYMBOL(zalloc_cpumask_var); /** * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena. * @mask: pointer to cpumask_var_t where the cpumask is returned * * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is * a nop (in <linux/cpumask.h>). * Either returns an allocated (zero-filled) cpumask, or causes the * system to panic. */void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask){	*mask = memblock_alloc(cpumask_size(), SMP_CACHE_BYTES);	if (!*mask)		panic("%s: Failed to allocate %u bytes\n", __func__,		      cpumask_size());} /** * free_cpumask_var - frees memory allocated for a struct cpumask. * @mask: cpumask to free * * This is safe on a NULL mask. */void free_cpumask_var(cpumask_var_t mask){	kfree(mask);}EXPORT_SYMBOL(free_cpumask_var); /** * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var * @mask: cpumask to free */void __init free_bootmem_cpumask_var(cpumask_var_t mask){	memblock_free_early(__pa(mask), cpumask_size());}#endif /** * cpumask_local_spread - select the i'th cpu with local numa cpu's first * @i: index number * @node: local numa_node * * This function selects an online CPU according to a numa aware policy; * local cpus are returned first, followed by non-local ones, then it * wraps around. * * It's not very efficient, but useful for setup. */unsigned int cpumask_local_spread(unsigned int i, int node){	int cpu, hk_flags;	const struct cpumask *mask; 	hk_flags = HK_FLAG_DOMAIN | HK_FLAG_MANAGED_IRQ;	mask = housekeeping_cpumask(hk_flags);	/* Wrap: we always want a cpu. */	i %= cpumask_weight(mask); 	if (node == NUMA_NO_NODE) {		for_each_cpu(cpu, mask) {			if (i-- == 0)				return cpu;		}	} else {		/* NUMA first. */		for_each_cpu_and(cpu, cpumask_of_node(node), mask) {			if (i-- == 0)				return cpu;		} 		for_each_cpu(cpu, mask) {			/* Skip NUMA nodes, done above. */			if (cpumask_test_cpu(cpu, cpumask_of_node(node)))				continue; 			if (i-- == 0)				return cpu;		}	}	BUG();}EXPORT_SYMBOL(cpumask_local_spread); static DEFINE_PER_CPU(int, distribute_cpu_mask_prev); /** * Returns an arbitrary cpu within srcp1 & srcp2. * * Iterated calls using the same srcp1 and srcp2 will be distributed within * their intersection. * * Returns >= nr_cpu_ids if the intersection is empty. */int cpumask_any_and_distribute(const struct cpumask *src1p,			       const struct cpumask *src2p){	int next, prev; 	/* NOTE: our first selection will skip 0. */	prev = __this_cpu_read(distribute_cpu_mask_prev); 	next = cpumask_next_and(prev, src1p, src2p);	if (next >= nr_cpu_ids)		next = cpumask_first_and(src1p, src2p); 	if (next < nr_cpu_ids)		__this_cpu_write(distribute_cpu_mask_prev, next); 	return next;}EXPORT_SYMBOL(cpumask_any_and_distribute);