1 /* Copyright (c) 2016 Facebook
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
7 #include "percpu_freelist.h"
9 int pcpu_freelist_init(struct pcpu_freelist *s)
13 s->freelist = alloc_percpu(struct pcpu_freelist_head);
17 for_each_possible_cpu(cpu) {
18 struct pcpu_freelist_head *head = per_cpu_ptr(s->freelist, cpu);
20 raw_spin_lock_init(&head->lock);
26 void pcpu_freelist_destroy(struct pcpu_freelist *s)
28 free_percpu(s->freelist);
31 static inline void __pcpu_freelist_push(struct pcpu_freelist_head *head,
32 struct pcpu_freelist_node *node)
34 raw_spin_lock(&head->lock);
35 node->next = head->first;
37 raw_spin_unlock(&head->lock);
40 void pcpu_freelist_push(struct pcpu_freelist *s,
41 struct pcpu_freelist_node *node)
43 struct pcpu_freelist_head *head = this_cpu_ptr(s->freelist);
45 __pcpu_freelist_push(head, node);
48 void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
51 struct pcpu_freelist_head *head;
53 int i, cpu, pcpu_entries;
55 pcpu_entries = nr_elems / num_possible_cpus() + 1;
58 /* disable irq to workaround lockdep false positive
59 * in bpf usage pcpu_freelist_populate() will never race
60 * with pcpu_freelist_push()
62 local_irq_save(flags);
63 for_each_possible_cpu(cpu) {
65 head = per_cpu_ptr(s->freelist, cpu);
66 __pcpu_freelist_push(head, buf);
74 local_irq_restore(flags);
77 struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
79 struct pcpu_freelist_head *head;
80 struct pcpu_freelist_node *node;
83 orig_cpu = cpu = raw_smp_processor_id();
85 head = per_cpu_ptr(s->freelist, cpu);
86 raw_spin_lock(&head->lock);
89 head->first = node->next;
90 raw_spin_unlock(&head->lock);
93 raw_spin_unlock(&head->lock);
94 cpu = cpumask_next(cpu, cpu_possible_mask);
95 if (cpu >= nr_cpu_ids)