Because READ_ONCE() now implies smp_read_barrier_depends(), the smp_read_barrier_depends() in get_ksm_page() is now redundant. This commit removes it and updates the comments.
Signed-off-by: Paul E. McKenney <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Michal Hocko <[email protected]> Cc: "Kirill A. Shutemov" <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "Aneesh Kumar K.V" <[email protected]> Cc: Claudio Imbrenda <[email protected]> Cc: <[email protected]> --- mm/ksm.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/mm/ksm.c b/mm/ksm.c index 6cb60f46cce5..7d70f923bc45 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -675,15 +675,8 @@ static struct page *get_ksm_page(struct stable_node *stable_node, bool lock_it) expected_mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); again: - kpfn = READ_ONCE(stable_node->kpfn); + kpfn = READ_ONCE(stable_node->kpfn); /* Address dependency. */ page = pfn_to_page(kpfn); - - /* - * page is computed from kpfn, so on most architectures reading - * page->mapping is naturally ordered after reading node->kpfn, - * but on Alpha we need to be more careful. - */ - smp_read_barrier_depends(); if (READ_ONCE(page->mapping) != expected_mapping) goto stale; -- 2.5.2
