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authorMatthew Wilcox <willy@infradead.org>2018-05-16 16:12:50 -0400
committerMatthew Wilcox <willy@infradead.org>2018-10-21 10:46:34 -0400
commit4c7472c0df2f889df417a37571e622e02b5058fe (patch)
tree15557c1b56edf6cc1f0092b59eb2145a80ce5a29 /mm/filemap.c
parent5c024e6a4ebc1740db9f0f075aaa476210108a97 (diff)
page cache: Convert find_get_entry to XArray
Slightly shorter and simpler code. Signed-off-by: Matthew Wilcox <willy@infradead.org>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c63
1 files changed, 28 insertions, 35 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 414efbdc95df..2bf9f0742082 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1382,47 +1382,40 @@ EXPORT_SYMBOL(page_cache_prev_miss);
*/
struct page *find_get_entry(struct address_space *mapping, pgoff_t offset)
{
- void **pagep;
+ XA_STATE(xas, &mapping->i_pages, offset);
struct page *head, *page;
rcu_read_lock();
repeat:
- page = NULL;
- pagep = radix_tree_lookup_slot(&mapping->i_pages, offset);
- if (pagep) {
- page = radix_tree_deref_slot(pagep);
- if (unlikely(!page))
- goto out;
- if (radix_tree_exception(page)) {
- if (radix_tree_deref_retry(page))
- goto repeat;
- /*
- * A shadow entry of a recently evicted page,
- * or a swap entry from shmem/tmpfs. Return
- * it without attempting to raise page count.
- */
- goto out;
- }
+ xas_reset(&xas);
+ page = xas_load(&xas);
+ if (xas_retry(&xas, page))
+ goto repeat;
+ /*
+ * A shadow entry of a recently evicted page, or a swap entry from
+ * shmem/tmpfs. Return it without attempting to raise page count.
+ */
+ if (!page || xa_is_value(page))
+ goto out;
- head = compound_head(page);
- if (!page_cache_get_speculative(head))
- goto repeat;
+ head = compound_head(page);
+ if (!page_cache_get_speculative(head))
+ goto repeat;
- /* The page was split under us? */
- if (compound_head(page) != head) {
- put_page(head);
- goto repeat;
- }
+ /* The page was split under us? */
+ if (compound_head(page) != head) {
+ put_page(head);
+ goto repeat;
+ }
- /*
- * Has the page moved?
- * This is part of the lockless pagecache protocol. See
- * include/linux/pagemap.h for details.
- */
- if (unlikely(page != *pagep)) {
- put_page(head);
- goto repeat;
- }
+ /*
+ * Has the page moved?
+ * This is part of the lockless pagecache protocol. See
+ * include/linux/pagemap.h for details.
+ */
+ if (unlikely(page != xas_reload(&xas))) {
+ put_page(head);
+ goto repeat;
}
out:
rcu_read_unlock();
@@ -1453,7 +1446,7 @@ struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset)
repeat:
page = find_get_entry(mapping, offset);
- if (page && !radix_tree_exception(page)) {
+ if (page && !xa_is_value(page)) {
lock_page(page);
/* Has the page been truncated? */
if (unlikely(page_mapping(page) != mapping)) {