mm: madvise: fix MADV_WILLNEED on shmem swapouts

MADV_WILLNEED currently does not read swapped out shmem pages back in.

0cd6144aadd2 ("mm + fs: prepare for non-page entries in page cache radix
trees") made find_get_page() filter exceptional radix tree entries but
failed to convert all find_get_page() callers that WANT exceptional
entries over to find_get_entry().  One of them is shmem swap readahead in
madvise, which now skips over any swap-out records.

Convert it to find_get_entry().

Fixes: 0cd6144aadd2 ("mm + fs: prepare for non-page entries in page cache radix trees")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/madvise.c b/mm/madvise.c
index 539eeb96b323bf649f83783e0dddcb4f907e1d6e..a402f8fdc68e94888ea177104524085c9f490fd5 100644 (file)
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -195,7 +195,7 @@ static void force_shm_swapin_readahead(struct vm_area_struct *vma,
        for (; start < end; start += PAGE_SIZE) {
                index = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
 
-               page = find_get_page(mapping, index);
+               page = find_get_entry(mapping, index);
                if (!radix_tree_exceptional_entry(page)) {
                        if (page)
                                page_cache_release(page);