1/*
2 * cpu_rmap.c: CPU affinity reverse-map support
3 * Copyright 2011 Solarflare Communications Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published
7 * by the Free Software Foundation, incorporated herein by reference.
8 */
9
10#include <linux/cpumask.h>
11#include <linux/gfp.h>
12#include <linux/slab.h>
13
14/**
15 * struct cpu_rmap - CPU affinity reverse-map
16 * @size: Number of objects to be reverse-mapped
17 * @used: Number of objects added
18 * @obj: Pointer to array of object pointers
19 * @near: For each CPU, the index and distance to the nearest object,
20 *      based on affinity masks
21 */
22struct cpu_rmap {
23	u16		size, used;
24	void		**obj;
25	struct {
26		u16	index;
27		u16	dist;
28	}		near[0];
29};
30#define CPU_RMAP_DIST_INF 0xffff
31
32extern struct cpu_rmap *alloc_cpu_rmap(unsigned int size, gfp_t flags);
33
34/**
35 * free_cpu_rmap - free CPU affinity reverse-map
36 * @rmap: Reverse-map allocated with alloc_cpu_rmap(), or %NULL
37 */
38static inline void free_cpu_rmap(struct cpu_rmap *rmap)
39{
40	kfree(rmap);
41}
42
43extern int cpu_rmap_add(struct cpu_rmap *rmap, void *obj);
44extern int cpu_rmap_update(struct cpu_rmap *rmap, u16 index,
45			   const struct cpumask *affinity);
46
47static inline u16 cpu_rmap_lookup_index(struct cpu_rmap *rmap, unsigned int cpu)
48{
49	return rmap->near[cpu].index;
50}
51
52static inline void *cpu_rmap_lookup_obj(struct cpu_rmap *rmap, unsigned int cpu)
53{
54	return rmap->obj[rmap->near[cpu].index];
55}
56
57#ifdef CONFIG_GENERIC_HARDIRQS
58
59/**
60 * alloc_irq_cpu_rmap - allocate CPU affinity reverse-map for IRQs
61 * @size: Number of objects to be mapped
62 *
63 * Must be called in process context.
64 */
65static inline struct cpu_rmap *alloc_irq_cpu_rmap(unsigned int size)
66{
67	return alloc_cpu_rmap(size, GFP_KERNEL);
68}
69extern void free_irq_cpu_rmap(struct cpu_rmap *rmap);
70
71extern int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq);
72
73#endif
74