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3d2d827f MT |
1 | /* Copyright (C) 2009 Red Hat, Inc. |
2 | * | |
3 | * See ../COPYING for licensing terms. | |
4 | */ | |
5 | ||
6 | #include <linux/mm.h> | |
7 | #include <linux/mmu_context.h> | |
5da779c3 | 8 | #include <linux/module.h> |
3d2d827f MT |
9 | #include <linux/sched.h> |
10 | ||
11 | #include <asm/mmu_context.h> | |
12 | ||
13 | /* | |
14 | * use_mm | |
15 | * Makes the calling kernel thread take on the specified | |
16 | * mm context. | |
17 | * Called by the retry thread execute retries within the | |
18 | * iocb issuer's mm context, so that copy_from/to_user | |
19 | * operations work seamlessly for aio. | |
20 | * (Note: this routine is intended to be called only | |
21 | * from a kernel thread context) | |
22 | */ | |
23 | void use_mm(struct mm_struct *mm) | |
24 | { | |
25 | struct mm_struct *active_mm; | |
26 | struct task_struct *tsk = current; | |
27 | ||
28 | task_lock(tsk); | |
29 | active_mm = tsk->active_mm; | |
f68e1480 MT |
30 | if (active_mm != mm) { |
31 | atomic_inc(&mm->mm_count); | |
32 | tsk->active_mm = mm; | |
33 | } | |
3d2d827f | 34 | tsk->mm = mm; |
3d2d827f MT |
35 | switch_mm(active_mm, mm, tsk); |
36 | task_unlock(tsk); | |
37 | ||
f68e1480 MT |
38 | if (active_mm != mm) |
39 | mmdrop(active_mm); | |
3d2d827f | 40 | } |
5da779c3 | 41 | EXPORT_SYMBOL_GPL(use_mm); |
3d2d827f MT |
42 | |
43 | /* | |
44 | * unuse_mm | |
45 | * Reverses the effect of use_mm, i.e. releases the | |
46 | * specified mm context which was earlier taken on | |
47 | * by the calling kernel thread | |
48 | * (Note: this routine is intended to be called only | |
49 | * from a kernel thread context) | |
50 | */ | |
51 | void unuse_mm(struct mm_struct *mm) | |
52 | { | |
53 | struct task_struct *tsk = current; | |
54 | ||
55 | task_lock(tsk); | |
298359c5 | 56 | sync_mm_rss(tsk, mm); |
3d2d827f MT |
57 | tsk->mm = NULL; |
58 | /* active_mm is still 'mm' */ | |
59 | enter_lazy_tlb(mm, tsk); | |
60 | task_unlock(tsk); | |
61 | } | |
5da779c3 | 62 | EXPORT_SYMBOL_GPL(unuse_mm); |