shmem: Convert shmem_partial_swap_usage to XArray

Simpler code because the xarray takes care of things like the limit and
dereferencing the slot.

Signed-off-by: Matthew Wilcox <willy@infradead.org>

diff --git a/mm/shmem.c b/mm/shmem.c
index 8e9bbfb7ed154ea0656c93d2983fcda1c6c3486c..5588205f42594ccf067beba03f1a3cb3b69bac47 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -676,29 +676,19 @@ static int shmem_free_swap(struct address_space *mapping,
 unsigned long shmem_partial_swap_usage(struct address_space *mapping,
                                                pgoff_t start, pgoff_t end)
 {
-       struct radix_tree_iter iter;
-       void __rcu **slot;
+       XA_STATE(xas, &mapping->i_pages, start);
        struct page *page;
        unsigned long swapped = 0;
 
        rcu_read_lock();
-
-       radix_tree_for_each_slot(slot, &mapping->i_pages, &iter, start) {
-               if (iter.index >= end)
-                       break;
-
-               page = radix_tree_deref_slot(slot);
-
-               if (radix_tree_deref_retry(page)) {
-                       slot = radix_tree_iter_retry(&iter);
+       xas_for_each(&xas, page, end - 1) {
+               if (xas_retry(&xas, page))
                        continue;
-               }
-
                if (xa_is_value(page))
                        swapped++;
 
                if (need_resched()) {
-                       slot = radix_tree_iter_resume(slot, &iter);
+                       xas_pause(&xas);
                        cond_resched_rcu();
                }
        }