uml: activate_mm: remove the dead PF_BORROWED_MM check

use_mm() was changed to use switch_mm() instead of activate_mm(), since
then nobody calls (and nobody should call) activate_mm() with
PF_BORROWED_MM bit set.

As Jeff Dike pointed out, we can also remove the "old != new" check, it is
always true.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 4 deletions

diff --git a/fs/aio.c b/fs/aio.c
index b5253e77eb2f..0fb3117ddd93 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -591,10 +591,6 @@ static void use_mm(struct mm_struct *mm)
         atomic_inc(&mm->mm_count);
         tsk->mm = mm;
         tsk->active_mm = mm;
-        /*
-         * Note that on UML this *requires* PF_BORROWED_MM to be set, otherwise
-         * it won't work. Update it accordingly if you change it here
-         */
         switch_mm(active_mm, mm, tsk);
         task_unlock(tsk);