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