diff options
| -rw-r--r-- | include/linux/pagemap.h | 2 | ||||
| -rw-r--r-- | mm/filemap.c | 73 |
2 files changed, 75 insertions, 0 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 0178b2040ea3..8689c32d628b 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -718,6 +718,8 @@ static inline struct page *find_subpage(struct page *head, pgoff_t index) unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start, pgoff_t end, struct folio_batch *fbatch); +unsigned filemap_get_folios_contig(struct address_space *mapping, + pgoff_t *start, pgoff_t end, struct folio_batch *fbatch); unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start, unsigned int nr_pages, struct page **pages); unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, diff --git a/mm/filemap.c b/mm/filemap.c index cb740a6b7227..2a9441afe337 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2197,6 +2197,79 @@ bool folio_more_pages(struct folio *folio, pgoff_t index, pgoff_t max) } /** + * filemap_get_folios_contig - Get a batch of contiguous folios + * @mapping: The address_space to search + * @start: The starting page index + * @end: The final page index (inclusive) + * @fbatch: The batch to fill + * + * filemap_get_folios_contig() works exactly like filemap_get_folios(), + * except the returned folios are guaranteed to be contiguous. This may + * not return all contiguous folios if the batch gets filled up. + * + * Return: The number of folios found. + * Also update @start to be positioned for traversal of the next folio. + */ + +unsigned filemap_get_folios_contig(struct address_space *mapping, + pgoff_t *start, pgoff_t end, struct folio_batch *fbatch) +{ + XA_STATE(xas, &mapping->i_pages, *start); + unsigned long nr; + struct folio *folio; + + rcu_read_lock(); + + for (folio = xas_load(&xas); folio && xas.xa_index <= end; + folio = xas_next(&xas)) { + if (xas_retry(&xas, folio)) + continue; + /* + * If the entry has been swapped out, we can stop looking. + * No current caller is looking for DAX entries. + */ + if (xa_is_value(folio)) + goto update_start; + + if (!folio_try_get_rcu(folio)) + goto retry; + + if (unlikely(folio != xas_reload(&xas))) + goto put_folio; + + if (!folio_batch_add(fbatch, folio)) { + nr = folio_nr_pages(folio); + + if (folio_test_hugetlb(folio)) + nr = 1; + *start = folio->index + nr; + goto out; + } + continue; +put_folio: + folio_put(folio); + +retry: + xas_reset(&xas); + } + +update_start: + nr = folio_batch_count(fbatch); + + if (nr) { + folio = fbatch->folios[nr - 1]; + if (folio_test_hugetlb(folio)) + *start = folio->index + 1; + else + *start = folio->index + folio_nr_pages(folio); + } +out: + rcu_read_unlock(); + return folio_batch_count(fbatch); +} +EXPORT_SYMBOL(filemap_get_folios_contig); + +/** * find_get_pages_contig - gang contiguous pagecache lookup * @mapping: The address_space to search * @index: The starting page index |