summaryrefslogtreecommitdiff
path: root/kernel/kthread.c
diff options
context:
space:
mode:
authorChristoph Hellwig <hch@lst.de>2020-08-12 04:33:47 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-12 20:57:59 +0300
commit3d13f313ce4c34c524ccc37986fe77172f601ff3 (patch)
treefd71a87be80c03601ab0e3be425fe45da116b5ba /kernel/kthread.c
parent428e2976a5bf7e7f5554286d7a5a33b8147b106a (diff)
downloadlinux-3d13f313ce4c34c524ccc37986fe77172f601ff3.tar.xz
uaccess: add force_uaccess_{begin,end} helpers
Add helpers to wrap the get_fs/set_fs magic for undoing any damange done by set_fs(KERNEL_DS). There is no real functional benefit, but this documents the intent of these calls better, and will allow stubbing the functions out easily for kernels builds that do not allow address space overrides in the future. [hch@lst.de: drop two incorrect hunks, fix a commit log typo] Link: http://lkml.kernel.org/r/20200714105505.935079-6-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Greentime Hu <green.hu@gmail.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Nick Hu <nickhu@andestech.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Link: http://lkml.kernel.org/r/20200710135706.537715-6-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/kthread.c')
-rw-r--r--kernel/kthread.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c
index b2807e7be772..3edaa380dc7b 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -1258,8 +1258,7 @@ void kthread_use_mm(struct mm_struct *mm)
if (active_mm != mm)
mmdrop(active_mm);
- to_kthread(tsk)->oldfs = get_fs();
- set_fs(USER_DS);
+ to_kthread(tsk)->oldfs = force_uaccess_begin();
}
EXPORT_SYMBOL_GPL(kthread_use_mm);
@@ -1274,7 +1273,7 @@ void kthread_unuse_mm(struct mm_struct *mm)
WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD));
WARN_ON_ONCE(!tsk->mm);
- set_fs(to_kthread(tsk)->oldfs);
+ force_uaccess_end(to_kthread(tsk)->oldfs);
task_lock(tsk);
sync_mm_rss(mm);