From ef8351241d6484ad4ff148cf2e034a27295f1f0d Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Tue, 31 Jan 2023 16:01:16 -0800 Subject: [PATCH] UPSTREAM: mm: introduce vm_flags_reset_once to replace WRITE_ONCE vm_flags updates Provide vm_flags_reset_once() and replace the vm_flags updates which used WRITE_ONCE() to prevent compiler optimizations. Link: https://lkml.kernel.org/r/20230201000116.1333160-1-surenb@google.com Fixes: 0cce31a0aa0e ("mm: replace vma->vm_flags direct modifications with modifier calls") Signed-off-by: Suren Baghdasaryan Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Acked-by: Michal Hocko Signed-off-by: Andrew Morton (cherry picked from commit 601c3c29dbeb049862faa00917f2daf094a71028) Bug: 161210518 Change-Id: Ied961a1bfbdc25b79268ba04515960c664052d61 Signed-off-by: Suren Baghdasaryan --- include/linux/mm.h | 7 +++++++ mm/mlock.c | 4 ++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index bf16a79e6c11..1efc75b9200f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -649,6 +649,13 @@ static inline void vm_flags_reset(struct vm_area_struct *vma, vm_flags_init(vma, flags); } +static inline void vm_flags_reset_once(struct vm_area_struct *vma, + vm_flags_t flags) +{ + mmap_assert_write_locked(vma->vm_mm); + WRITE_ONCE(ACCESS_PRIVATE(vma, __vm_flags), flags); +} + static inline void vm_flags_set(struct vm_area_struct *vma, vm_flags_t flags) { diff --git a/mm/mlock.c b/mm/mlock.c index c17984cb14d1..9738d49bbc24 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -380,7 +380,7 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma, */ if (newflags & VM_LOCKED) newflags |= VM_IO; - vm_flags_reset(vma, newflags); + vm_flags_reset_once(vma, newflags); lru_add_drain(); walk_page_range(vma->vm_mm, start, end, &mlock_walk_ops, NULL); @@ -388,7 +388,7 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma, if (newflags & VM_IO) { newflags &= ~VM_IO; - vm_flags_reset(vma, newflags); + vm_flags_reset_once(vma, newflags); } }