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 */
94struct parallel_data {
95 struct padata_shell *ps;
96 struct padata_list __percpu *reorder_list;
97 struct padata_serial_queue __percpu *squeue;
98 refcount_t refcnt;
99 unsigned int seq_nr;
100 unsigned int processed;
101 int cpu;
102 struct padata_cpumask cpumask;
103};
104
105/**
106 * struct padata_shell - Wrapper around struct parallel_data, its
107 * purpose is to allow the underlying control structure to be replaced
108 * on the fly using RCU.
109 *
110 * @pinst: padat instance.
111 * @pd: Actual parallel_data structure which may be substituted on the fly.
112 * @opd: Pointer to old pd to be freed by padata_replace.
113 * @list: List entry in padata_instance list.
114 */
115struct padata_shell {
116 struct padata_instance *pinst;
117 struct parallel_data __rcu *pd;
118 struct parallel_data *opd;
119 struct list_head list;
120};
121
122/**
123 * struct padata_mt_job - represents one multithreaded job
124 *
125 * @thread_fn: Called for each chunk of work that a padata thread does.
126 * @fn_arg: The thread function argument.
127 * @start: The start of the job (units are job-specific).
128 * @size: size of this node's work (units are job-specific).
129 * @align: Ranges passed to the thread function fall on this boundary, with the
130 * possible exceptions of the beginning and end of the job.
131 * @min_chunk: The minimum chunk size in job-specific units. This allows
132 * the client to communicate the minimum amount of work that's
133 * appropriate for one worker thread to do at once.
134 * @max_threads: Max threads to use for the job, actual number may be less
135 * depending on task size and minimum chunk size.
136 * @numa_aware: Distribute jobs to different nodes with CPU in a round robin fashion.
137 */
138struct padata_mt_job {
139 void (*thread_fn)(unsigned long start, unsigned long end, void *arg);
140 void *fn_arg;
141 unsigned long start;
142 unsigned long size;
143 unsigned long align;
144 unsigned long min_chunk;
145 int max_threads;
146 bool numa_aware;
147};
148
149/**
150 * struct padata_instance - The overall control structure.
151 *
152 * @cpu_online_node: Linkage for CPU online callback.
153 * @cpu_dead_node: Linkage for CPU offline callback.
154 * @parallel_wq: The workqueue used for parallel work.
155 * @serial_wq: The workqueue used for serial work.
156 * @pslist: List of padata_shell objects attached to this instance.
157 * @cpumask: User supplied cpumasks for parallel and serial works.
158 * @kobj: padata instance kernel object.
159 * @lock: padata instance lock.
160 * @flags: padata flags.
161 */
162struct padata_instance {
163 struct hlist_node cpu_online_node;
164 struct hlist_node cpu_dead_node;
165 struct workqueue_struct *parallel_wq;
166 struct workqueue_struct *serial_wq;
167 struct list_head pslist;
168 struct padata_cpumask cpumask;
169 struct kobject kobj;
170 struct mutex lock;
171 u8 flags;
172#define PADATA_INIT 1
173#define PADATA_RESET 2
174#define PADATA_INVALID 4
175};
176
177#ifdef CONFIG_PADATA
178extern void __init padata_init(void);
179extern struct padata_instance *padata_alloc(const char *name);
180extern void padata_free(struct padata_instance *pinst);
181extern struct padata_shell *padata_alloc_shell(struct padata_instance *pinst);
182extern void padata_free_shell(struct padata_shell *ps);
183extern int padata_do_parallel(struct padata_shell *ps,
184 struct padata_priv *padata, int *cb_cpu);
185extern void padata_do_serial(struct padata_priv *padata);
186extern void __init padata_do_multithreaded(struct padata_mt_job *job);
187extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
188 cpumask_var_t cpumask);
189#else
190static inline void __init padata_init(void) {}
191static inline void __init padata_do_multithreaded(struct padata_mt_job *job)
192{
193 job->thread_fn(job->start, job->start + job->size, job->fn_arg);
194}
195#endif
196
197#endif
198