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