summaryrefslogtreecommitdiff
path: root/mm/filemap.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index c4d4ace9cc70..291bb3e0957a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2282,6 +2282,60 @@ out:
EXPORT_SYMBOL(filemap_get_folios_contig);
/**
+ * filemap_get_folios_tag - Get a batch of folios matching @tag
+ * @mapping: The address_space to search
+ * @start: The starting page index
+ * @end: The final page index (inclusive)
+ * @tag: The tag index
+ * @fbatch: The batch to fill
+ *
+ * Same as filemap_get_folios(), but only returning folios tagged with @tag.
+ *
+ * Return: The number of folios found.
+ * Also update @start to index the next folio for traversal.
+ */
+unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start,
+ pgoff_t end, xa_mark_t tag, struct folio_batch *fbatch)
+{
+ XA_STATE(xas, &mapping->i_pages, *start);
+ struct folio *folio;
+
+ rcu_read_lock();
+ while ((folio = find_get_entry(&xas, end, tag)) != NULL) {
+ /*
+ * Shadow entries should never be tagged, but this iteration
+ * is lockless so there is a window for page reclaim to evict
+ * a page we saw tagged. Skip over it.
+ */
+ if (xa_is_value(folio))
+ continue;
+ if (!folio_batch_add(fbatch, folio)) {
+ unsigned long nr = folio_nr_pages(folio);
+
+ if (folio_test_hugetlb(folio))
+ nr = 1;
+ *start = folio->index + nr;
+ goto out;
+ }
+ }
+ /*
+ * We come here when there is no page beyond @end. We take care to not
+ * overflow the index @start as it confuses some of the callers. This
+ * breaks the iteration when there is a page at index -1 but that is
+ * already broke anyway.
+ */
+ if (end == (pgoff_t)-1)
+ *start = (pgoff_t)-1;
+ else
+ *start = end + 1;
+out:
+ rcu_read_unlock();
+
+ return folio_batch_count(fbatch);
+}
+EXPORT_SYMBOL(filemap_get_folios_tag);
+
+/**
* find_get_pages_range_tag - Find and return head pages matching @tag.
* @mapping: the address_space to search
* @index: the starting page index