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