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>
This commit is contained in:
Matthew Wilcox 2017-12-04 03:28:00 -05:00
parent c121d3bb71
commit 7ae3424fb4

View File

@ -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();
}
}