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/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
 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