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Commit c1901cd3 authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

page cache: Convert find_get_entries_tag to XArray 



Slightly shorter and simpler code.

Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
parent a6906972

include/linux/pagemap.h

+1 −1
Original line number Diff line number Diff line
@@ -373,7 +373,7 @@ static inline unsigned find_get_pages_tag(struct address_space *mapping, 
					nr_pages, pages);

}

unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,

			int tag, unsigned int nr_entries,

			xa_mark_t tag, unsigned int nr_entries,

			struct page **entries, pgoff_t *indices);



struct page *grab_cache_page_write_begin(struct address_space *mapping,

mm/filemap.c

+24 −30
Original line number Diff line number Diff line
@@ -1866,57 +1866,51 @@ EXPORT_SYMBOL(find_get_pages_range_tag); 
 * @tag.

 */

unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,

			int tag, unsigned int nr_entries,

			xa_mark_t tag, unsigned int nr_entries,

			struct page **entries, pgoff_t *indices)

{

	void **slot;

	XA_STATE(xas, &mapping->i_pages, start);

	struct page *page;

	unsigned int ret = 0;

	struct radix_tree_iter iter;



	if (!nr_entries)

		return 0;



	rcu_read_lock();

	radix_tree_for_each_tagged(slot, &mapping->i_pages, &iter, start, tag) {

		struct page *head, *page;

repeat:

		page = radix_tree_deref_slot(slot);

		if (unlikely(!page))

			continue;

		if (radix_tree_exception(page)) {

			if (radix_tree_deref_retry(page)) {

				slot = radix_tree_iter_retry(&iter);

	xas_for_each_marked(&xas, page, ULONG_MAX, tag) {

		struct page *head;

		if (xas_retry(&xas, page))

			continue;

			}



		/*

		 * A shadow entry of a recently evicted page, a swap

		 * entry from shmem/tmpfs or a DAX entry.  Return it

		 * without attempting to raise page count.

		 */

		if (xa_is_value(page))

			goto export;

		}



		head = compound_head(page);

		if (!page_cache_get_speculative(head))

			goto repeat;

			goto retry;



		/* The page was split under us? */

		if (compound_head(page) != head) {

			put_page(head);

			goto repeat;

		}

		if (compound_head(page) != head)

			goto put_page;



		/* Has the page moved? */

		if (unlikely(page != *slot)) {

			put_page(head);

			goto repeat;

		}

		if (unlikely(page != xas_reload(&xas)))

			goto put_page;



export:

		indices[ret] = iter.index;

		indices[ret] = xas.xa_index;

		entries[ret] = page;

		if (++ret == nr_entries)

			break;

		continue;

put_page:

		put_page(head);

retry:

		xas_reset(&xas);

	}

	rcu_read_unlock();

	return ret;