[PATCH 33/62] page cache: Convert page_cache_next_hole to XArray

[Matthew Wilcox]

From: Matthew Wilcox <mawil...@microsoft.com>

Use xas_find_any() to scan the entries instead of doing a lookup from
the top of the tree each time.

Signed-off-by: Matthew Wilcox <mawil...@microsoft.com>
---
 mm/filemap.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 1c03b0ea105e..accc350f9544 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1349,20 +1349,15 @@ int __lock_page_or_retry(struct page *page, struct 
mm_struct *mm,
 pgoff_t page_cache_next_hole(struct address_space *mapping,
                             pgoff_t index, unsigned long max_scan)
 {
-       unsigned long i;
-
-       for (i = 0; i < max_scan; i++) {
-               struct page *page;
+       XA_STATE(xas, index);
 
-               page = radix_tree_lookup(&mapping->pages, index);
-               if (!page || xa_is_value(page))
-                       break;
-               index++;
-               if (index == 0)
+       while (max_scan--) {
+               void *entry = xas_find_any(&mapping->pages, &xas);
+               if (!entry || xa_is_value(entry))
                        break;
        }
 
-       return index;
+       return xas.xa_index;
 }
 EXPORT_SYMBOL(page_cache_next_hole);
 
-- 
2.15.0