[PATCH v9 49/61] shmem: Convert shmem_partial_swap_usage to XArray

From: Matthew Wilcox
Date: Tue Mar 13 2018 - 09:27:16 EST


From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>

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

Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
---
mm/shmem.c | 18 +++---------------
1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index cfbffb4b47a2..707430003ec7 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->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);
- 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();
}
}
--
2.16.1