thp: avoid VM_BUG_ON page_count(page) false positives in __collapse_huge_page_copy

Speculative cache pagecache lookups can elevate the refcount from
under us, so avoid the false positive. If the refcount is < 2 we'll be
notified by a VM_BUG_ON in put_page_testzero as there are two
put_page(src_page) in a row before returning from this function.

Signed-off-by: Andrea Arcangeli <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Reviewed-by: Johannes Weiner <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Petr Holasek <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions