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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 | */ | |
22 | void 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 | } | |
43 | EXPORT_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 | */ | |
53 | void 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 | } | |
64 | EXPORT_SYMBOL_GPL(unuse_mm); |