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
   9 #ifndef PADATA_H
  10 #define PADATA_H
  11
  12 #include <linux/compiler_types.h>
  13 #include <linux/workqueue.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/list.h>
  16 #include <linux/notifier.h>
  17 #include <linux/kobject.h>
  18
  19 #define PADATA_CPU_SERIAL   0x01
  20 #define PADATA_CPU_PARALLEL 0x02
  21
  22 /**
  23  * struct padata_priv -  Embedded to the users data structure.
  24  *
  25  * @list: List entry, to attach to the padata lists.
  26  * @pd: Pointer to the internal control structure.
  27  * @cb_cpu: Callback cpu for serializatioon.
  28  * @cpu: Cpu for parallelization.
  29  * @seq_nr: Sequence number of the parallelized data object.
  30  * @info: Used to pass information from the parallel to the serial function.
  31  * @parallel: Parallel execution function.
  32  * @serial: Serial complete function.
  33  */
  34 struct padata_priv {
  35         struct list_head        list;
  36         struct parallel_data    *pd;
  37         int                     cb_cpu;
  38         int                     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
  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_parallel_queue - The percpu padata parallel queue
  71  *
  72  * @parallel: List to wait for parallelization.
  73  * @reorder: List to wait for reordering after parallel processing.
  74  * @serial: List to wait for serialization after reordering.
  75  * @pwork: work struct for parallelization.
  76  * @swork: work struct for serialization.
  77  * @work: work struct for parallelization.
  78  * @num_obj: Number of objects that are processed by this cpu.
  79  */
  80 struct padata_parallel_queue {
  81        struct padata_list    parallel;
  82        struct padata_list    reorder;
  83        struct work_struct    work;
  84        atomic_t              num_obj;
  85 };
  86
  87 /**
  88  * struct padata_cpumask - The cpumasks for the parallel/serial workers
  89  *
  90  * @pcpu: cpumask for the parallel workers.
  91  * @cbcpu: cpumask for the serial (callback) workers.
  92  */
  93 struct padata_cpumask {
  94         cpumask_var_t   pcpu;
  95         cpumask_var_t   cbcpu;
  96 };
  97
  98 /**
  99  * struct parallel_data - Internal control structure, covers everything
 100  * that depends on the cpumask in use.
 101  *
 102  * @sh: padata_shell object.
 103  * @pqueue: percpu padata queues used for parallelization.
 104  * @squeue: percpu padata queues used for serialuzation.
 105  * @reorder_objects: Number of objects waiting in the reorder queues.
 106  * @refcnt: Number of objects holding a reference on this parallel_data.
 107  * @max_seq_nr:  Maximal used sequence number.
 108  * @processed: Number of already processed objects.
 109  * @cpu: Next CPU to be processed.
 110  * @cpumask: The cpumasks in use for parallel and serial workers.
 111  * @reorder_work: work struct for reordering.
 112  * @lock: Reorder lock.
 113  */
 114 struct parallel_data {
 115         struct padata_shell             *ps;
 116         struct padata_parallel_queue    __percpu *pqueue;
 117         struct padata_serial_queue      __percpu *squeue;
 118         atomic_t                        reorder_objects;
 119         atomic_t                        refcnt;
 120         atomic_t                        seq_nr;
 121         unsigned int                    processed;
 122         int                             cpu;
 123         struct padata_cpumask           cpumask;
 124         struct work_struct              reorder_work;
 125         spinlock_t                      lock ____cacheline_aligned;
 126 };
 127
 128 /**
 129  * struct padata_shell - Wrapper around struct parallel_data, its
 130  * purpose is to allow the underlying control structure to be replaced
 131  * on the fly using RCU.
 132  *
 133  * @pinst: padat instance.
 134  * @pd: Actual parallel_data structure which may be substituted on the fly.
 135  * @opd: Pointer to old pd to be freed by padata_replace.
 136  * @list: List entry in padata_instance list.
 137  */
 138 struct padata_shell {
 139         struct padata_instance          *pinst;
 140         struct parallel_data __rcu      *pd;
 141         struct parallel_data            *opd;
 142         struct list_head                list;
 143 };
 144
 145 /**
 146  * struct padata_instance - The overall control structure.
 147  *
 148  * @cpu_notifier: cpu hotplug notifier.
 149  * @parallel_wq: The workqueue used for parallel work.
 150  * @serial_wq: The workqueue used for serial work.
 151  * @pslist: List of padata_shell objects attached to this instance.
 152  * @cpumask: User supplied cpumasks for parallel and serial works.
 153  * @rcpumask: Actual cpumasks based on user cpumask and cpu_online_mask.
 154  * @omask: Temporary storage used to compute the notification mask.
 155  * @cpumask_change_notifier: Notifiers chain for user-defined notify
 156  *            callbacks that will be called when either @pcpu or @cbcpu
 157  *            or both cpumasks change.
 158  * @kobj: padata instance kernel object.
 159  * @lock: padata instance lock.
 160  * @flags: padata flags.
 161  */
 162 struct padata_instance {
 163         struct hlist_node                node;
 164         struct workqueue_struct         *parallel_wq;
 165         struct workqueue_struct         *serial_wq;
 166         struct list_head                pslist;
 167         struct padata_cpumask           cpumask;
 168         struct padata_cpumask           rcpumask;
 169         cpumask_var_t                   omask;
 170         struct blocking_notifier_head    cpumask_change_notifier;
 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 extern struct padata_instance *padata_alloc_possible(const char *name);
 180 extern void padata_free(struct padata_instance *pinst);
 181 extern struct padata_shell *padata_alloc_shell(struct padata_instance *pinst);
 182 extern void padata_free_shell(struct padata_shell *ps);
 183 extern int padata_do_parallel(struct padata_shell *ps,
 184                               struct padata_priv *padata, int *cb_cpu);
 185 extern void padata_do_serial(struct padata_priv *padata);
 186 extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
 187                               cpumask_var_t cpumask);
 188 extern int padata_start(struct padata_instance *pinst);
 189 extern void padata_stop(struct padata_instance *pinst);
 190 extern int padata_register_cpumask_notifier(struct padata_instance *pinst,
 191                                             struct notifier_block *nblock);
 192 extern int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
 193                                               struct notifier_block *nblock);
 194 #endif