thp: fix huge zero page logic for page with pfn == 0

Current implementation of huge zero page uses pfn value 0 to indicate
that the page hasn't allocated yet.  It assumes that buddy page
allocator can't return page with pfn == 0.

Let's rework the code to store 'struct page *' of huge zero page, not
its pfn.  This way we can avoid the weak assumption.

[[email protected]: fix sparse warning]
Signed-off-by: Kirill A. Shutemov <[email protected]>
Reported-by: Minchan Kim <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Reviewed-by: Andrea Arcangeli <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: Wu Fengguang <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions