Commit 3d2d827f5ca5e32816194119d5c980c7e04474a6
Committed by
Linus Torvalds
Linus Torvalds
1 parent
425fbf047c
mm: move use_mm/unuse_mm from aio.c to mm/
Anyone who wants to do copy to/from user from a kernel thread, needs use_mm (like what fs/aio has). Move that into mm/, to make reusing and exporting easier down the line, and make aio use it. Next intended user, besides aio, will be vhost-net. Acked-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Showing 4 changed files with 66 additions and 47 deletions Side-by-side Diff
fs/aio.c
| ... | ... | @@ -24,6 +24,7 @@ |
| 24 | 24 | #include <linux/file.h> |
| 25 | 25 | #include <linux/mm.h> |
| 26 | 26 | #include <linux/mman.h> |
| 27 | +#include <linux/mmu_context.h> | |
| 27 | 28 | #include <linux/slab.h> |
| 28 | 29 | #include <linux/timer.h> |
| 29 | 30 | #include <linux/aio.h> |
| ... | ... | @@ -34,7 +35,6 @@ |
| 34 | 35 | |
| 35 | 36 | #include <asm/kmap_types.h> |
| 36 | 37 | #include <asm/uaccess.h> |
| 37 | -#include <asm/mmu_context.h> | |
| 38 | 38 | |
| 39 | 39 | #if DEBUG > 1 |
| 40 | 40 | #define dprintk printk |
| ... | ... | @@ -592,51 +592,6 @@ |
| 592 | 592 | |
| 593 | 593 | rcu_read_unlock(); |
| 594 | 594 | return ret; |
| 595 | -} | |
| 596 | - | |
| 597 | -/* | |
| 598 | - * use_mm | |
| 599 | - * Makes the calling kernel thread take on the specified | |
| 600 | - * mm context. | |
| 601 | - * Called by the retry thread execute retries within the | |
| 602 | - * iocb issuer's mm context, so that copy_from/to_user | |
| 603 | - * operations work seamlessly for aio. | |
| 604 | - * (Note: this routine is intended to be called only | |
| 605 | - * from a kernel thread context) | |
| 606 | - */ | |
| 607 | -static void use_mm(struct mm_struct *mm) | |
| 608 | -{ | |
| 609 | - struct mm_struct *active_mm; | |
| 610 | - struct task_struct *tsk = current; | |
| 611 | - | |
| 612 | - task_lock(tsk); | |
| 613 | - active_mm = tsk->active_mm; | |
| 614 | - atomic_inc(&mm->mm_count); | |
| 615 | - tsk->mm = mm; | |
| 616 | - tsk->active_mm = mm; | |
| 617 | - switch_mm(active_mm, mm, tsk); | |
| 618 | - task_unlock(tsk); | |
| 619 | - | |
| 620 | - mmdrop(active_mm); | |
| 621 | -} | |
| 622 | - | |
| 623 | -/* | |
| 624 | - * unuse_mm | |
| 625 | - * Reverses the effect of use_mm, i.e. releases the | |
| 626 | - * specified mm context which was earlier taken on | |
| 627 | - * by the calling kernel thread | |
| 628 | - * (Note: this routine is intended to be called only | |
| 629 | - * from a kernel thread context) | |
| 630 | - */ | |
| 631 | -static void unuse_mm(struct mm_struct *mm) | |
| 632 | -{ | |
| 633 | - struct task_struct *tsk = current; | |
| 634 | - | |
| 635 | - task_lock(tsk); | |
| 636 | - tsk->mm = NULL; | |
| 637 | - /* active_mm is still 'mm' */ | |
| 638 | - enter_lazy_tlb(mm, tsk); | |
| 639 | - task_unlock(tsk); | |
| 640 | 595 | } |
| 641 | 596 | |
| 642 | 597 | /* |
include/linux/mmu_context.h
mm/Makefile
| ... | ... | @@ -11,7 +11,7 @@ |
| 11 | 11 | maccess.o page_alloc.o page-writeback.o \ |
| 12 | 12 | readahead.o swap.o truncate.o vmscan.o shmem.o \ |
| 13 | 13 | prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \ |
| 14 | - page_isolation.o mm_init.o $(mmu-y) | |
| 14 | + page_isolation.o mm_init.o mmu_context.o $(mmu-y) | |
| 15 | 15 | obj-y += init-mm.o |
| 16 | 16 | |
| 17 | 17 | obj-$(CONFIG_PROC_PAGE_MONITOR) += pagewalk.o |
mm/mmu_context.c
| 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> | |
| 8 | +#include <linux/sched.h> | |
| 9 | + | |
| 10 | +#include <asm/mmu_context.h> | |
| 11 | + | |
| 12 | +/* | |
| 13 | + * use_mm | |
| 14 | + * Makes the calling kernel thread take on the specified | |
| 15 | + * mm context. | |
| 16 | + * Called by the retry thread execute retries within the | |
| 17 | + * iocb issuer's mm context, so that copy_from/to_user | |
| 18 | + * operations work seamlessly for aio. | |
| 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 | + atomic_inc(&mm->mm_count); | |
| 30 | + tsk->mm = mm; | |
| 31 | + tsk->active_mm = mm; | |
| 32 | + switch_mm(active_mm, mm, tsk); | |
| 33 | + task_unlock(tsk); | |
| 34 | + | |
| 35 | + mmdrop(active_mm); | |
| 36 | +} | |
| 37 | + | |
| 38 | +/* | |
| 39 | + * unuse_mm | |
| 40 | + * Reverses the effect of use_mm, i.e. releases the | |
| 41 | + * specified mm context which was earlier taken on | |
| 42 | + * by the calling kernel thread | |
| 43 | + * (Note: this routine is intended to be called only | |
| 44 | + * from a kernel thread context) | |
| 45 | + */ | |
| 46 | +void unuse_mm(struct mm_struct *mm) | |
| 47 | +{ | |
| 48 | + struct task_struct *tsk = current; | |
| 49 | + | |
| 50 | + task_lock(tsk); | |
| 51 | + tsk->mm = NULL; | |
| 52 | + /* active_mm is still 'mm' */ | |
| 53 | + enter_lazy_tlb(mm, tsk); | |
| 54 | + task_unlock(tsk); | |
| 55 | +} |