// SPDX-License-Identifier: GPL-2.0-only/* Copyright (c) 2016 Facebook */#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_res_spin_lock_init(&head->lock);		head->first = NULL;	}	raw_res_spin_lock_init(&s->extralist.lock);	s->extralist.first = NULL;	return 0;} void pcpu_freelist_destroy(struct pcpu_freelist *s){	free_percpu(s->freelist);} static inline void pcpu_freelist_push_node(struct pcpu_freelist_head *head,					   struct pcpu_freelist_node *node){	node->next = head->first;	WRITE_ONCE(head->first, node);} static inline bool ___pcpu_freelist_push(struct pcpu_freelist_head *head,					 struct pcpu_freelist_node *node){	if (raw_res_spin_lock(&head->lock))		return false;	pcpu_freelist_push_node(head, node);	raw_res_spin_unlock(&head->lock);	return true;} void __pcpu_freelist_push(struct pcpu_freelist *s,			struct pcpu_freelist_node *node){	struct pcpu_freelist_head *head;	int cpu, this_cpu; 	if (___pcpu_freelist_push(this_cpu_ptr(s->freelist), node))		return; 	this_cpu = raw_smp_processor_id();	while (true) {		for_each_cpu_wrap(cpu, cpu_possible_mask, this_cpu) {			if (cpu == this_cpu)				continue; 			head = per_cpu_ptr(s->freelist, cpu);			if (___pcpu_freelist_push(head, node))				return;		} 		/*		 * Push cannot fail. Use the extra list when none of the		 * per-CPU freelists can accept the node.		 */		if (___pcpu_freelist_push(&s->extralist, node))			return;	}} void pcpu_freelist_push(struct pcpu_freelist *s,			struct pcpu_freelist_node *node){	unsigned long flags; 	local_irq_save(flags);	__pcpu_freelist_push(s, node);	local_irq_restore(flags);} void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,			    u32 nr_elems){	struct pcpu_freelist_head *head;	unsigned int cpu, cpu_idx, i, j, n, m; 	n = nr_elems / num_possible_cpus();	m = nr_elems % num_possible_cpus(); 	cpu_idx = 0;	for_each_possible_cpu(cpu) {		head = per_cpu_ptr(s->freelist, cpu);		j = n + (cpu_idx < m ? 1 : 0);		for (i = 0; i < j; i++) {			/* No locking required as this is not visible yet. */			pcpu_freelist_push_node(head, buf);			buf += elem_size;		}		cpu_idx++;	}} static struct pcpu_freelist_node *___pcpu_freelist_pop(struct pcpu_freelist *s){	struct pcpu_freelist_node *node = NULL;	struct pcpu_freelist_head *head;	int cpu; 	for_each_cpu_wrap(cpu, cpu_possible_mask, raw_smp_processor_id()) {		head = per_cpu_ptr(s->freelist, cpu);		if (!READ_ONCE(head->first))			continue;		if (raw_res_spin_lock(&head->lock))			continue;		node = head->first;		if (node) {			WRITE_ONCE(head->first, node->next);			raw_res_spin_unlock(&head->lock);			return node;		}		raw_res_spin_unlock(&head->lock);	} 	/* Per-CPU lists are empty or unavailable, try the extra list. */	head = &s->extralist;	if (!READ_ONCE(head->first))		return NULL;	if (raw_res_spin_lock(&head->lock))		return NULL;	node = head->first;	if (node)		WRITE_ONCE(head->first, node->next);	raw_res_spin_unlock(&head->lock);	return node;} struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *s){	return ___pcpu_freelist_pop(s);} struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s){	struct pcpu_freelist_node *ret;	unsigned long flags; 	local_irq_save(flags);	ret = __pcpu_freelist_pop(s);	local_irq_restore(flags);	return ret;}