/* Copyright (c) 2016 Facebook * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. */#include "percpu_freelist.h" int pcpu_freelist_init(struct pcpu_freelist *s){	int cpu; 	s->freelist = alloc_percpu(struct pcpu_freelist_head);	if (!s->freelist)		return -ENOMEM; 	for_each_possible_cpu(cpu) {		struct pcpu_freelist_head *head = per_cpu_ptr(s->freelist, cpu); 		raw_spin_lock_init(&head->lock);		head->first = NULL;	}	return 0;} void pcpu_freelist_destroy(struct pcpu_freelist *s){	free_percpu(s->freelist);} static inline void __pcpu_freelist_push(struct pcpu_freelist_head *head,					struct pcpu_freelist_node *node){	raw_spin_lock(&head->lock);	node->next = head->first;	head->first = node;	raw_spin_unlock(&head->lock);} void pcpu_freelist_push(struct pcpu_freelist *s,			struct pcpu_freelist_node *node){	struct pcpu_freelist_head *head = this_cpu_ptr(s->freelist); 	__pcpu_freelist_push(head, node);} void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,			    u32 nr_elems){	struct pcpu_freelist_head *head;	unsigned long flags;	int i, cpu, pcpu_entries; 	pcpu_entries = nr_elems / num_possible_cpus() + 1;	i = 0; 	/* disable irq to workaround lockdep false positive	 * in bpf usage pcpu_freelist_populate() will never race	 * with pcpu_freelist_push()	 */	local_irq_save(flags);	for_each_possible_cpu(cpu) {again:		head = per_cpu_ptr(s->freelist, cpu);		__pcpu_freelist_push(head, buf);		i++;		buf += elem_size;		if (i == nr_elems)			break;		if (i % pcpu_entries)			goto again;	}	local_irq_restore(flags);} struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s){	struct pcpu_freelist_head *head;	struct pcpu_freelist_node *node;	int orig_cpu, cpu; 	orig_cpu = cpu = raw_smp_processor_id();	while (1) {		head = per_cpu_ptr(s->freelist, cpu);		raw_spin_lock(&head->lock);		node = head->first;		if (node) {			head->first = node->next;			raw_spin_unlock(&head->lock);			return node;		}		raw_spin_unlock(&head->lock);		cpu = cpumask_next(cpu, cpu_possible_mask);		if (cpu >= nr_cpu_ids)			cpu = 0;		if (cpu == orig_cpu)			return NULL;	}}