/* Copyright (C) 2009 Red Hat, Inc. * * See ../COPYING for licensing terms. */ #include <linux/mm.h> #include <linux/mmu_context.h> #include <linux/export.h> #include <linux/sched.h> #include <asm/mmu_context.h> /* * use_mm * Makes the calling kernel thread take on the specified * mm context. * Called by the retry thread execute retries within the * iocb issuer's mm context, so that copy_from/to_user * operations work seamlessly for aio. * (Note: this routine is intended to be called only * from a kernel thread context) */ void use_mm(struct mm_struct *mm) { struct mm_struct *active_mm; struct task_struct *tsk = current; task_lock(tsk); active_mm = tsk->active_mm; if (active_mm != mm) { atomic_inc(&mm->mm_count); tsk->active_mm = mm; } tsk->mm = mm; switch_mm(active_mm, mm, tsk); task_unlock(tsk); if (active_mm != mm) mmdrop(active_mm); } EXPORT_SYMBOL_GPL(use_mm); /* * unuse_mm * Reverses the effect of use_mm, i.e. releases the * specified mm context which was earlier taken on * by the calling kernel thread * (Note: this routine is intended to be called only * from a kernel thread context) */ void unuse_mm(struct mm_struct *mm) { struct task_struct *tsk = current; task_lock(tsk); sync_mm_rss(tsk, mm); tsk->mm = NULL; /* active_mm is still 'mm' */ enter_lazy_tlb(mm, tsk); task_unlock(tsk); } EXPORT_SYMBOL_GPL(unuse_mm);