LXR linux/include/linux/padata.h

   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 */
 141struct padata_mt_job {
 142        void (*thread_fn)(unsigned long start, unsigned long end, void *arg);
 143        void                    *fn_arg;
 144        unsigned long           start;
 145        unsigned long           size;
 146        unsigned long           align;
 147        unsigned long           min_chunk;
 148        int                     max_threads;
 149};
 150
 151/**
 152 * struct padata_instance - The overall control structure.
 153 *
 154 * @cpu_online_node: Linkage for CPU online callback.
 155 * @cpu_dead_node: Linkage for CPU offline callback.
 156 * @parallel_wq: The workqueue used for parallel work.
 157 * @serial_wq: The workqueue used for serial work.
 158 * @pslist: List of padata_shell objects attached to this instance.
 159 * @cpumask: User supplied cpumasks for parallel and serial works.
 160 * @kobj: padata instance kernel object.
 161 * @lock: padata instance lock.
 162 * @flags: padata flags.
 163 */
 164struct padata_instance {
 165        struct hlist_node               cpu_online_node;
 166        struct hlist_node               cpu_dead_node;
 167        struct workqueue_struct         *parallel_wq;
 168        struct workqueue_struct         *serial_wq;
 169        struct list_head                pslist;
 170        struct padata_cpumask           cpumask;
 171        struct kobject                   kobj;
 172        struct mutex                     lock;
 173        u8                               flags;
 174#define PADATA_INIT     1
 175#define PADATA_RESET    2
 176#define PADATA_INVALID  4
 177};
 178
 179#ifdef CONFIG_PADATA
 180extern void __init padata_init(void);
 181#else
 182static inline void __init padata_init(void) {}
 183#endif
 184
 185extern struct padata_instance *padata_alloc(const char *name);
 186extern void padata_free(struct padata_instance *pinst);
 187extern struct padata_shell *padata_alloc_shell(struct padata_instance *pinst);
 188extern void padata_free_shell(struct padata_shell *ps);
 189extern int padata_do_parallel(struct padata_shell *ps,
 190                              struct padata_priv *padata, int *cb_cpu);
 191extern void padata_do_serial(struct padata_priv *padata);
 192extern void __init padata_do_multithreaded(struct padata_mt_job *job);
 193extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
 194                              cpumask_var_t cpumask);
 195#endif
 196