1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * padata.h - header for the padata parallelization interface
4 *
5 * Copyright (C) 2008, 2009 secunet Security Networks AG
6 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
7 *
8 * Copyright (c) 2020 Oracle and/or its affiliates.
9 * Author: Daniel Jordan <daniel.m.jordan@oracle.com>
10 */
11
12#ifndef PADATA_H
13#define PADATA_H
14
15#include <linux/refcount.h>
16#include <linux/compiler_types.h>
17#include <linux/workqueue.h>
18#include <linux/spinlock.h>
19#include <linux/list.h>
20#include <linux/kobject.h>
21
22#define PADATA_CPU_SERIAL   0x01
23#define PADATA_CPU_PARALLEL 0x02
24
25/**
26 * struct padata_priv - Represents one job
27 *
28 * @list: List entry, to attach to the padata lists.
29 * @pd: Pointer to the internal control structure.
30 * @cb_cpu: Callback cpu for serializatioon.
31 * @seq_nr: Sequence number of the parallelized data object.
32 * @info: Used to pass information from the parallel to the serial function.
33 * @parallel: Parallel execution function.
34 * @serial: Serial complete function.
35 */
36struct padata_priv {
37	struct list_head	list;
38	struct parallel_data	*pd;
39	int			cb_cpu;
40	unsigned int		seq_nr;
41	int			info;
42	void                    (*parallel)(struct padata_priv *padata);
43	void                    (*serial)(struct padata_priv *padata);
44};
45
46/**
47 * struct padata_list - one per work type per CPU
48 *
49 * @list: List head.
50 * @lock: List lock.
51 */
52struct padata_list {
53	struct list_head        list;
54	spinlock_t              lock;
55};
56
57/**
58* struct padata_serial_queue - The percpu padata serial queue
59*
60* @serial: List to wait for serialization after reordering.
61* @work: work struct for serialization.
62* @pd: Backpointer to the internal control structure.
63*/
64struct padata_serial_queue {
65       struct padata_list    serial;
66       struct work_struct    work;
67       struct parallel_data *pd;
68};
69
70/**
71 * struct padata_cpumask - The cpumasks for the parallel/serial workers
72 *
73 * @pcpu: cpumask for the parallel workers.
74 * @cbcpu: cpumask for the serial (callback) workers.
75 */
76struct padata_cpumask {
77	cpumask_var_t	pcpu;
78	cpumask_var_t	cbcpu;
79};
80
81/**
82 * struct parallel_data - Internal control structure, covers everything
83 * that depends on the cpumask in use.
84 *
85 * @ps: padata_shell object.
86 * @reorder_list: percpu reorder lists
87 * @squeue: percpu padata queues used for serialuzation.
88 * @refcnt: Number of objects holding a reference on this parallel_data.
89 * @seq_nr: Sequence number of the parallelized data object.
90 * @processed: Number of already processed objects.
91 * @cpu: Next CPU to be processed.
92 * @cpumask: The cpumasks in use for parallel and serial workers.
93 * @reorder_work: work struct for reordering.
94 * @lock: Reorder lock.
95 */
96struct parallel_data {
97	struct padata_shell		*ps;
98	struct padata_list		__percpu *reorder_list;
99	struct padata_serial_queue	__percpu *squeue;
100	refcount_t			refcnt;
101	unsigned int			seq_nr;
102	unsigned int			processed;
103	int				cpu;
104	struct padata_cpumask		cpumask;
105	struct work_struct		reorder_work;
106	spinlock_t                      ____cacheline_aligned lock;
107};
108
109/**
110 * struct padata_shell - Wrapper around struct parallel_data, its
111 * purpose is to allow the underlying control structure to be replaced
112 * on the fly using RCU.
113 *
114 * @pinst: padat instance.
115 * @pd: Actual parallel_data structure which may be substituted on the fly.
116 * @opd: Pointer to old pd to be freed by padata_replace.
117 * @list: List entry in padata_instance list.
118 */
119struct padata_shell {
120	struct padata_instance		*pinst;
121	struct parallel_data __rcu	*pd;
122	struct parallel_data		*opd;
123	struct list_head		list;
124};
125
126/**
127 * struct padata_mt_job - represents one multithreaded job
128 *
129 * @thread_fn: Called for each chunk of work that a padata thread does.
130 * @fn_arg: The thread function argument.
131 * @start: The start of the job (units are job-specific).
132 * @size: size of this node's work (units are job-specific).
133 * @align: Ranges passed to the thread function fall on this boundary, with the
134 *         possible exceptions of the beginning and end of the job.
135 * @min_chunk: The minimum chunk size in job-specific units.  This allows
136 *             the client to communicate the minimum amount of work that's
137 *             appropriate for one worker thread to do at once.
138 * @max_threads: Max threads to use for the job, actual number may be less
139 *               depending on task size and minimum chunk size.
140 * @numa_aware: Distribute jobs to different nodes with CPU in a round robin fashion.
141 */
142struct padata_mt_job {
143	void (*thread_fn)(unsigned long start, unsigned long end, void *arg);
144	void			*fn_arg;
145	unsigned long		start;
146	unsigned long		size;
147	unsigned long		align;
148	unsigned long		min_chunk;
149	int			max_threads;
150	bool			numa_aware;
151};
152
153/**
154 * struct padata_instance - The overall control structure.
155 *
156 * @cpu_online_node: Linkage for CPU online callback.
157 * @cpu_dead_node: Linkage for CPU offline callback.
158 * @parallel_wq: The workqueue used for parallel work.
159 * @serial_wq: The workqueue used for serial work.
160 * @pslist: List of padata_shell objects attached to this instance.
161 * @cpumask: User supplied cpumasks for parallel and serial works.
162 * @kobj: padata instance kernel object.
163 * @lock: padata instance lock.
164 * @flags: padata flags.
165 */
166struct padata_instance {
167	struct hlist_node		cpu_online_node;
168	struct hlist_node		cpu_dead_node;
169	struct workqueue_struct		*parallel_wq;
170	struct workqueue_struct		*serial_wq;
171	struct list_head		pslist;
172	struct padata_cpumask		cpumask;
173	struct kobject                   kobj;
174	struct mutex			 lock;
175	u8				 flags;
176#define	PADATA_INIT	1
177#define	PADATA_RESET	2
178#define	PADATA_INVALID	4
179};
180
181#ifdef CONFIG_PADATA
182extern void __init padata_init(void);
183extern struct padata_instance *padata_alloc(const char *name);
184extern void padata_free(struct padata_instance *pinst);
185extern struct padata_shell *padata_alloc_shell(struct padata_instance *pinst);
186extern void padata_free_shell(struct padata_shell *ps);
187extern int padata_do_parallel(struct padata_shell *ps,
188			      struct padata_priv *padata, int *cb_cpu);
189extern void padata_do_serial(struct padata_priv *padata);
190extern void __init padata_do_multithreaded(struct padata_mt_job *job);
191extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
192			      cpumask_var_t cpumask);
193#else
194static inline void __init padata_init(void) {}
195static inline void __init padata_do_multithreaded(struct padata_mt_job *job)
196{
197	job->thread_fn(job->start, job->start + job->size, job->fn_arg);
198}
199#endif
200
201#endif
202