linux/include/linux/sched/task.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_SCHED_TASK_H
   3#define _LINUX_SCHED_TASK_H
   4
   5/*
   6 * Interface between the scheduler and various task lifetime (fork()/exit())
   7 * functionality:
   8 */
   9
  10#include <linux/sched.h>
  11#include <linux/uaccess.h>
  12
  13struct task_struct;
  14struct rusage;
  15union thread_union;
  16struct css_set;
  17
  18/* All the bits taken by the old clone syscall. */
  19#define CLONE_LEGACY_FLAGS 0xffffffffULL
  20
  21struct kernel_clone_args {
  22        u64 flags;
  23        int __user *pidfd;
  24        int __user *child_tid;
  25        int __user *parent_tid;
  26        int exit_signal;
  27        unsigned long stack;
  28        unsigned long stack_size;
  29        unsigned long tls;
  30        pid_t *set_tid;
  31        /* Number of elements in *set_tid */
  32        size_t set_tid_size;
  33        int cgroup;
  34        int io_thread;
  35        struct cgroup *cgrp;
  36        struct css_set *cset;
  37};
  38
  39/*
  40 * This serializes "schedule()" and also protects
  41 * the run-queue from deletions/modifications (but
  42 * _adding_ to the beginning of the run-queue has
  43 * a separate lock).
  44 */
  45extern rwlock_t tasklist_lock;
  46extern spinlock_t mmlist_lock;
  47
  48extern union thread_union init_thread_union;
  49extern struct task_struct init_task;
  50
  51extern int lockdep_tasklist_lock_is_held(void);
  52
  53extern asmlinkage void schedule_tail(struct task_struct *prev);
  54extern void init_idle(struct task_struct *idle, int cpu);
  55
  56extern int sched_fork(unsigned long clone_flags, struct task_struct *p);
  57extern void sched_post_fork(struct task_struct *p);
  58extern void sched_dead(struct task_struct *p);
  59
  60void __noreturn do_task_dead(void);
  61
  62extern void proc_caches_init(void);
  63
  64extern void fork_init(void);
  65
  66extern void release_task(struct task_struct * p);
  67
  68extern int copy_thread(unsigned long, unsigned long, unsigned long,
  69                       struct task_struct *, unsigned long);
  70
  71extern void flush_thread(void);
  72
  73#ifdef CONFIG_HAVE_EXIT_THREAD
  74extern void exit_thread(struct task_struct *tsk);
  75#else
  76static inline void exit_thread(struct task_struct *tsk)
  77{
  78}
  79#endif
  80extern void do_group_exit(int);
  81
  82extern void exit_files(struct task_struct *);
  83extern void exit_itimers(struct signal_struct *);
  84
  85extern pid_t kernel_clone(struct kernel_clone_args *kargs);
  86struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node);
  87struct task_struct *fork_idle(int);
  88struct mm_struct *copy_init_mm(void);
  89extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
  90extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
  91int kernel_wait(pid_t pid, int *stat);
  92
  93extern void free_task(struct task_struct *tsk);
  94
  95/* sched_exec is called by processes performing an exec */
  96#ifdef CONFIG_SMP
  97extern void sched_exec(void);
  98#else
  99#define sched_exec()   {}
 100#endif
 101
 102static inline struct task_struct *get_task_struct(struct task_struct *t)
 103{
 104        refcount_inc(&t->usage);
 105        return t;
 106}
 107
 108extern void __put_task_struct(struct task_struct *t);
 109
 110static inline void put_task_struct(struct task_struct *t)
 111{
 112        if (refcount_dec_and_test(&t->usage))
 113                __put_task_struct(t);
 114}
 115
 116static inline void put_task_struct_many(struct task_struct *t, int nr)
 117{
 118        if (refcount_sub_and_test(nr, &t->usage))
 119                __put_task_struct(t);
 120}
 121
 122void put_task_struct_rcu_user(struct task_struct *task);
 123
 124#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
 125extern int arch_task_struct_size __read_mostly;
 126#else
 127# define arch_task_struct_size (sizeof(struct task_struct))
 128#endif
 129
 130#ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST
 131/*
 132 * If an architecture has not declared a thread_struct whitelist we
 133 * must assume something there may need to be copied to userspace.
 134 */
 135static inline void arch_thread_struct_whitelist(unsigned long *offset,
 136                                                unsigned long *size)
 137{
 138        *offset = 0;
 139        /* Handle dynamically sized thread_struct. */
 140        *size = arch_task_struct_size - offsetof(struct task_struct, thread);
 141}
 142#endif
 143
 144#ifdef CONFIG_VMAP_STACK
 145static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 146{
 147        return t->stack_vm_area;
 148}
 149#else
 150static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 151{
 152        return NULL;
 153}
 154#endif
 155
 156/*
 157 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
 158 * subscriptions and synchronises with wait4().  Also used in procfs.  Also
 159 * pins the final release of task.io_context.  Also protects ->cpuset and
 160 * ->cgroup.subsys[]. And ->vfork_done.
 161 *
 162 * Nests both inside and outside of read_lock(&tasklist_lock).
 163 * It must not be nested with write_lock_irq(&tasklist_lock),
 164 * neither inside nor outside.
 165 */
 166static inline void task_lock(struct task_struct *p)
 167{
 168        spin_lock(&p->alloc_lock);
 169}
 170
 171static inline void task_unlock(struct task_struct *p)
 172{
 173        spin_unlock(&p->alloc_lock);
 174}
 175
 176#endif /* _LINUX_SCHED_TASK_H */
 177
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