1/* Copyright (C) 2009 Red Hat, Inc.
2 *
3 * See ../COPYING for licensing terms.
4 */
5
6#include <linux/mm.h>
7#include <linux/sched.h>
8#include <linux/sched/mm.h>
9#include <linux/sched/task.h>
10#include <linux/mmu_context.h>
11#include <linux/export.h>
12
13#include <asm/mmu_context.h>
14
15/*
16 * use_mm
17 * Makes the calling kernel thread take on the specified
18 * mm context.
19 * (Note: this routine is intended to be called only
20 * from a kernel thread context)
21 */
22void use_mm(struct mm_struct *mm)
23{
24 struct mm_struct *active_mm;
25 struct task_struct *tsk = current;
26
27 task_lock(tsk);
28 active_mm = tsk->active_mm;
29 if (active_mm != mm) {
30 mmgrab(mm);
31 tsk->active_mm = mm;
32 }
33 tsk->mm = mm;
34 switch_mm(active_mm, mm, tsk);
35 task_unlock(tsk);
36#ifdef finish_arch_post_lock_switch
37 finish_arch_post_lock_switch();
38#endif
39
40 if (active_mm != mm)
41 mmdrop(active_mm);
42}
43EXPORT_SYMBOL_GPL(use_mm);
44
45/*
46 * unuse_mm
47 * Reverses the effect of use_mm, i.e. releases the
48 * specified mm context which was earlier taken on
49 * by the calling kernel thread
50 * (Note: this routine is intended to be called only
51 * from a kernel thread context)
52 */
53void unuse_mm(struct mm_struct *mm)
54{
55 struct task_struct *tsk = current;
56
57 task_lock(tsk);
58 sync_mm_rss(mm);
59 tsk->mm = NULL;
60 /* active_mm is still 'mm' */
61 enter_lazy_tlb(mm, tsk);
62 task_unlock(tsk);
63}
64EXPORT_SYMBOL_GPL(unuse_mm);
65