From: Yu Zhao <yuzhao@xxxxxxxxxx> Subject: mm/shmem: make find_get_pages_range() work for huge page find_get_pages_range() and find_get_pages_range_tag() already correctly increment reference count on head when seeing compound page, but they may still use page index from tail. Page index from tail is always zero, so these functions don't work on huge shmem. This hasn't been a problem because, AFAIK, nobody calls these functions on (huge) shmem. Fix them anyway just in case. Link: http://lkml.kernel.org/r/20190110030838.84446-1-yuzhao@xxxxxxxxxx Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx> Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Amir Goldstein <amir73il@xxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: "Darrick J . Wong" <darrick.wong@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Souptick Joarder <jrdr.linux@xxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: "Kirill A . Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/filemap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/filemap.c~mm-shmem-make-find_get_pages_range-work-for-huge-page +++ a/mm/filemap.c @@ -1789,7 +1789,7 @@ unsigned find_get_pages_range(struct add pages[ret] = page; if (++ret == nr_pages) { - *start = page->index + 1; + *start = xas.xa_index + 1; goto out; } continue; @@ -1927,7 +1927,7 @@ unsigned find_get_pages_range_tag(struct pages[ret] = page; if (++ret == nr_pages) { - *index = page->index + 1; + *index = xas.xa_index + 1; goto out; } continue; _
