diff options
Diffstat (limited to 'kernel/kthread.c')
| -rw-r--r-- | kernel/kthread.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index b84fc7eec035..8e3d2d7fdf5e 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -1,13 +1,17 @@ // SPDX-License-Identifier: GPL-2.0-only /* Kernel thread helper functions. * Copyright (C) 2004 IBM Corporation, Rusty Russell. + * Copyright (C) 2009 Red Hat, Inc. * * Creation is done via kthreadd, so that we get a clean environment * even if we're invoked from userspace (think modprobe, hotplug cpu, * etc.). */ #include <uapi/linux/sched/types.h> +#include <linux/mm.h> +#include <linux/mmu_context.h> #include <linux/sched.h> +#include <linux/sched/mm.h> #include <linux/sched/task.h> #include <linux/kthread.h> #include <linux/completion.h> @@ -25,6 +29,7 @@ #include <linux/numa.h> #include <trace/events/sched.h> + static DEFINE_SPINLOCK(kthread_create_lock); static LIST_HEAD(kthread_create_list); struct task_struct *kthreadd_task; @@ -48,6 +53,7 @@ struct kthread { unsigned int cpu; int (*threadfn)(void *); void *data; + mm_segment_t oldfs; struct completion parked; struct completion exited; #ifdef CONFIG_BLK_CGROUP @@ -1220,6 +1226,61 @@ void kthread_destroy_worker(struct kthread_worker *worker) } EXPORT_SYMBOL(kthread_destroy_worker); +/** + * kthread_use_mm - make the calling kthread operate on an address space + * @mm: address space to operate on + */ +void kthread_use_mm(struct mm_struct *mm) +{ + struct mm_struct *active_mm; + struct task_struct *tsk = current; + + WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD)); + WARN_ON_ONCE(tsk->mm); + + task_lock(tsk); + active_mm = tsk->active_mm; + if (active_mm != mm) { + mmgrab(mm); + tsk->active_mm = mm; + } + tsk->mm = mm; + switch_mm(active_mm, mm, tsk); + task_unlock(tsk); +#ifdef finish_arch_post_lock_switch + finish_arch_post_lock_switch(); +#endif + + if (active_mm != mm) + mmdrop(active_mm); + + to_kthread(tsk)->oldfs = get_fs(); + set_fs(USER_DS); +} +EXPORT_SYMBOL_GPL(kthread_use_mm); + +/** + * kthread_unuse_mm - reverse the effect of kthread_use_mm() + * @mm: address space to operate on + */ +void kthread_unuse_mm(struct mm_struct *mm) +{ + struct task_struct *tsk = current; + + WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD)); + WARN_ON_ONCE(!tsk->mm); + + set_fs(to_kthread(tsk)->oldfs); + + task_lock(tsk); + sync_mm_rss(mm); + tsk->mm = NULL; + /* active_mm is still 'mm' */ + enter_lazy_tlb(mm, tsk); + task_unlock(tsk); +} +EXPORT_SYMBOL_GPL(kthread_unuse_mm); + #ifdef CONFIG_BLK_CGROUP /** * kthread_associate_blkcg - associate blkcg to current kthread |