[v6,49/99] shmem: Convert shmem_partial_swap_usage to XArray

Commit Message

Matthew Wilcox (Oracle) Jan. 17, 2018, 8:21 p.m. UTC

From: Matthew Wilcox <[e-mail]>

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

Signed-off-by: Matthew Wilcox <[e-mail]>
---
 mm/shmem.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

Patch

diff --git a/mm/shmem.c b/mm/shmem.c
index 5a2226e06f8c..4dbcfb436bd1 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -658,29 +658,17 @@  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 **slot;
+	XA_STATE(xas, &mapping->pages, start);
 	struct page *page;
 	unsigned long swapped = 0;
 
 	rcu_read_lock();
-
-	radix_tree_for_each_slot(slot, &mapping->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);
-			continue;
-		}
-
+	xas_for_each(&xas, page, end - 1) {
 		if (xa_is_value(page))
 			swapped++;
 
 		if (need_resched()) {
-			slot = radix_tree_iter_resume(slot, &iter);
+			xas_pause(&xas);
 			cond_resched_rcu();
 		}
 	}