The patch titled
uml: activate_mm: remove the dead PF_BORROWED_MM check
has been added to the -mm tree. Its filename is
uml-activate_mm-remove-the-dead-pf_borrowed_mm-check.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: uml: activate_mm: remove the dead PF_BORROWED_MM check
From: Oleg Nesterov <oleg@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Jeff Dike <jdike@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/aio.c | 4 ----
include/asm-um/mmu_context.h | 12 +++---------
2 files changed, 3 insertions(+), 13 deletions(-)
diff -puN fs/aio.c~uml-activate_mm-remove-the-dead-pf_borrowed_mm-check fs/aio.c
--- a/fs/aio.c~uml-activate_mm-remove-the-dead-pf_borrowed_mm-check
+++ a/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);
diff -puN include/asm-um/mmu_context.h~uml-activate_mm-remove-the-dead-pf_borrowed_mm-check include/asm-um/mmu_context.h
--- a/include/asm-um/mmu_context.h~uml-activate_mm-remove-the-dead-pf_borrowed_mm-check
+++ a/include/asm-um/mmu_context.h
@@ -22,16 +22,10 @@ extern void force_flush_all(void);
static inline void activate_mm(struct mm_struct *old, struct mm_struct *new)
{
/*
- * This is called by fs/exec.c and fs/aio.c. In the first case, for an
- * exec, we don't need to do anything as we're called from userspace
- * and thus going to use a new host PID. In the second, we're called
- * from a kernel thread, and thus need to go doing the mmap's on the
- * host. Since they're very expensive, we want to avoid that as far as
- * possible.
+ * This is called by fs/exec.c and sys_unshare()
+ * when the new ->mm is used for the first time.
*/
- if (old != new && (current->flags & PF_BORROWED_MM))
- __switch_mm(&new->context.id);
-
+ __switch_mm(&new->context.id);
arch_dup_mmap(old, new);
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
signals-fix-sigqueue_free-vs-__exit_signal-race.patch
uml-activate_mm-remove-the-dead-pf_borrowed_mm-check.patch
posix-timers-timer_delete-remove-the-bogus-it_process-=-null-check.patch
posix-timers-release_posix_timer-kill-the-bogus-put_task_struct-it_process.patch
signals-sigqueue_free-dont-free-sigqueue-if-it-is-queued.patch
signals-introduce-sigqueue_cancelled.patch
posix-timers-use-sigqueue_cancelled-when-the-timer-is-destroyed.patch
signals-collect_signal-remove-the-unneeded-sigismember-check.patch
signals-collect_signal-simplify-the-still_pending-logic.patch
put_pid-make-sure-we-dont-free-the-live-pid.patch
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