diff options
Diffstat (limited to 'include/linux/sched/task.h')
| -rw-r--r-- | include/linux/sched/task.h | 71 |
1 files changed, 57 insertions, 14 deletions
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index 357e0068497c..525aa2a632b2 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -7,6 +7,8 @@ * functionality: */ +#include <linux/rcupdate.h> +#include <linux/refcount.h> #include <linux/sched.h> #include <linux/uaccess.h> @@ -23,7 +25,12 @@ struct kernel_clone_args { int __user *pidfd; int __user *child_tid; int __user *parent_tid; + const char *name; int exit_signal; + u32 kthread:1; + u32 io_thread:1; + u32 user_worker:1; + u32 no_files:1; unsigned long stack; unsigned long stack_size; unsigned long tls; @@ -31,13 +38,12 @@ struct kernel_clone_args { /* Number of elements in *set_tid */ size_t set_tid_size; int cgroup; - int io_thread; - int kthread; int idle; int (*fn)(void *); void *fn_arg; struct cgroup *cgrp; struct css_set *cset; + unsigned int kill_seq; }; /* @@ -57,8 +63,9 @@ extern int lockdep_tasklist_lock_is_held(void); extern asmlinkage void schedule_tail(struct task_struct *prev); extern void init_idle(struct task_struct *idle, int cpu); -extern int sched_fork(unsigned long clone_flags, struct task_struct *p); -extern void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs); +extern int sched_fork(u64 clone_flags, struct task_struct *p); +extern int sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs); +extern void sched_cancel_fork(struct task_struct *p); extern void sched_post_fork(struct task_struct *p); extern void sched_dead(struct task_struct *p); @@ -89,9 +96,12 @@ extern void exit_files(struct task_struct *); extern void exit_itimers(struct task_struct *); extern pid_t kernel_clone(struct kernel_clone_args *kargs); +struct task_struct *copy_process(struct pid *pid, int trace, int node, + struct kernel_clone_args *args); struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node); struct task_struct *fork_idle(int); -extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); +extern pid_t kernel_thread(int (*fn)(void *), void *arg, const char *name, + unsigned long flags); extern pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags); extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); int kernel_wait(pid_t pid, int *stat); @@ -99,11 +109,7 @@ int kernel_wait(pid_t pid, int *stat); extern void free_task(struct task_struct *tsk); /* sched_exec is called by processes performing an exec */ -#ifdef CONFIG_SMP extern void sched_exec(void); -#else -#define sched_exec() {} -#endif static inline struct task_struct *get_task_struct(struct task_struct *t) { @@ -111,14 +117,50 @@ static inline struct task_struct *get_task_struct(struct task_struct *t) return t; } +static inline struct task_struct *tryget_task_struct(struct task_struct *t) +{ + return refcount_inc_not_zero(&t->usage) ? t : NULL; +} + extern void __put_task_struct(struct task_struct *t); +extern void __put_task_struct_rcu_cb(struct rcu_head *rhp); static inline void put_task_struct(struct task_struct *t) { - if (refcount_dec_and_test(&t->usage)) - __put_task_struct(t); + if (!refcount_dec_and_test(&t->usage)) + return; + + /* + * Under PREEMPT_RT, we can't call __put_task_struct + * in atomic context because it will indirectly + * acquire sleeping locks. The same is true if the + * current process has a mutex enqueued (blocked on + * a PI chain). + * + * In !RT, it is always safe to call __put_task_struct(). + * Though, in order to simplify the code, resort to the + * deferred call too. + * + * call_rcu() will schedule __put_task_struct_rcu_cb() + * to be called in process context. + * + * __put_task_struct() is called when + * refcount_dec_and_test(&t->usage) succeeds. + * + * This means that it can't "conflict" with + * put_task_struct_rcu_user() which abuses ->rcu the same + * way; rcu_users has a reference so task->usage can't be + * zero after rcu_users 1 -> 0 transition. + * + * delayed_free_task() also uses ->rcu, but it is only called + * when it fails to fork a process. Therefore, there is no + * way it can conflict with __put_task_struct(). + */ + call_rcu(&t->rcu, __put_task_struct_rcu_cb); } +DEFINE_FREE(put_task, struct task_struct *, if (_T) put_task_struct(_T)) + static inline void put_task_struct_many(struct task_struct *t, int nr) { if (refcount_sub_and_test(nr, &t->usage)) @@ -168,9 +210,8 @@ static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) * pins the final release of task.io_context. Also protects ->cpuset and * ->cgroup.subsys[]. And ->vfork_done. And ->sysvshm.shm_clist. * - * Nests both inside and outside of read_lock(&tasklist_lock). - * It must not be nested with write_lock_irq(&tasklist_lock), - * neither inside nor outside. + * Nests inside of read_lock(&tasklist_lock). It must not be nested with + * write_lock_irq(&tasklist_lock), neither inside nor outside. */ static inline void task_lock(struct task_struct *p) { @@ -182,4 +223,6 @@ static inline void task_unlock(struct task_struct *p) spin_unlock(&p->alloc_lock); } +DEFINE_GUARD(task_lock, struct task_struct *, task_lock(_T), task_unlock(_T)) + #endif /* _LINUX_SCHED_TASK_H */ |