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authorSuren Baghdasaryan <surenb@google.com>2023-01-31 16:01:16 -0800
committerAndrew Morton <akpm@linux-foundation.org>2023-02-09 16:51:41 -0800
commit601c3c29dbeb049862faa00917f2daf094a71028 (patch)
tree24e4ec4694356281c6ee9e12858f52a889d977da
parent7e4a32c0e8adafdda6161635c9046e6c1e8b95b5 (diff)
downloadlinux-601c3c29dbeb049862faa00917f2daf094a71028.tar.gz
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 <surenb@google.com> Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--include/linux/mm.h7
-rw-r--r--mm/mlock.c4
2 files changed, 9 insertions, 2 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 27b34f7730e7..0ed0cb2401f5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -642,6 +642,13 @@ 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 ed49459e343e..617469fce96d 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);
}
}