From 3ece58a270cd1e5026282abe778bd50db7a11d08 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 16 May 2018 18:00:33 -0400 Subject: [PATCH] page cache: Convert find_get_pages_contig to XArray There's no direct replacement for radix_tree_for_each_contig() in the XArray API as it's an unusual thing to do. Instead, open-code a loop using xas_next(). This removes the only user of radix_tree_for_each_contig() so delete the iterator from the API and the test suite code for it. Signed-off-by: Matthew Wilcox --- .clang-format | 1 - include/linux/radix-tree.h | 17 --------- mm/filemap.c | 53 +++++++++++--------------- tools/testing/radix-tree/regression3.c | 23 ----------- 4 files changed, 22 insertions(+), 72 deletions(-) diff --git a/.clang-format b/.clang-format index 1d5da22e0ba50c..e6080f5834a356 100644 --- a/.clang-format +++ b/.clang-format @@ -323,7 +323,6 @@ ForEachMacros: - 'protocol_for_each_card' - 'protocol_for_each_dev' - 'queue_for_each_hw_ctx' - - 'radix_tree_for_each_contig' - 'radix_tree_for_each_slot' - 'radix_tree_for_each_tagged' - 'rbtree_postorder_for_each_entry_safe' diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index d55de428a58913..023e888e1163d0 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -522,23 +522,6 @@ static __always_inline void __rcu **radix_tree_next_slot(void __rcu **slot, slot || (slot = radix_tree_next_chunk(root, iter, 0)) ; \ slot = radix_tree_next_slot(slot, iter, 0)) -/** - * radix_tree_for_each_contig - iterate over contiguous slots - * - * @slot: the void** variable for pointer to slot - * @root: the struct radix_tree_root pointer - * @iter: the struct radix_tree_iter pointer - * @start: iteration starting index - * - * @slot points to radix tree slot, @iter->index contains its index. - */ -#define radix_tree_for_each_contig(slot, root, iter, start) \ - for (slot = radix_tree_iter_init(iter, start) ; \ - slot || (slot = radix_tree_next_chunk(root, iter, \ - RADIX_TREE_ITER_CONTIG)) ; \ - slot = radix_tree_next_slot(slot, iter, \ - RADIX_TREE_ITER_CONTIG)) - /** * radix_tree_for_each_tagged - iterate over tagged slots * diff --git a/mm/filemap.c b/mm/filemap.c index b72c39fe61c24a..089b675981008b 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1721,57 +1721,43 @@ unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start, unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, unsigned int nr_pages, struct page **pages) { - struct radix_tree_iter iter; - void **slot; + XA_STATE(xas, &mapping->i_pages, index); + struct page *page; unsigned int ret = 0; if (unlikely(!nr_pages)) return 0; rcu_read_lock(); - radix_tree_for_each_contig(slot, &mapping->i_pages, &iter, index) { - struct page *head, *page; -repeat: - page = radix_tree_deref_slot(slot); - /* The hole, there no reason to continue */ - if (unlikely(!page)) - break; - - if (radix_tree_exception(page)) { - if (radix_tree_deref_retry(page)) { - slot = radix_tree_iter_retry(&iter); - continue; - } - /* - * A shadow entry of a recently evicted page, - * or a swap entry from shmem/tmpfs. Stop - * looking for contiguous pages. - */ + for (page = xas_load(&xas); page; page = xas_next(&xas)) { + struct page *head; + if (xas_retry(&xas, page)) + continue; + /* + * If the entry has been swapped out, we can stop looking. + * No current caller is looking for DAX entries. + */ + if (xa_is_value(page)) break; - } 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; /* * must check mapping and index after taking the ref. * otherwise we can get both false positives and false * negatives, which is just confusing to the caller. */ - if (page->mapping == NULL || page_to_pgoff(page) != iter.index) { + if (!page->mapping || page_to_pgoff(page) != xas.xa_index) { put_page(page); break; } @@ -1779,6 +1765,11 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, pages[ret] = page; if (++ret == nr_pages) break; + continue; +put_page: + put_page(head); +retry: + xas_reset(&xas); } rcu_read_unlock(); return ret; diff --git a/tools/testing/radix-tree/regression3.c b/tools/testing/radix-tree/regression3.c index ace2543c3edab3..9f9a3b280f56d3 100644 --- a/tools/testing/radix-tree/regression3.c +++ b/tools/testing/radix-tree/regression3.c @@ -69,21 +69,6 @@ void regression3_test(void) continue; } } - radix_tree_delete(&root, 1); - - first = true; - radix_tree_for_each_contig(slot, &root, &iter, 0) { - printv(2, "contig %ld %p\n", iter.index, *slot); - if (first) { - radix_tree_insert(&root, 1, ptr); - first = false; - } - if (radix_tree_deref_retry(*slot)) { - printv(2, "retry at %ld\n", iter.index); - slot = radix_tree_iter_retry(&iter); - continue; - } - } radix_tree_for_each_slot(slot, &root, &iter, 0) { printv(2, "slot %ld %p\n", iter.index, *slot); @@ -93,14 +78,6 @@ void regression3_test(void) } } - radix_tree_for_each_contig(slot, &root, &iter, 0) { - printv(2, "contig %ld %p\n", iter.index, *slot); - if (!iter.index) { - printv(2, "next at %ld\n", iter.index); - slot = radix_tree_iter_resume(slot, &iter); - } - } - radix_tree_tag_set(&root, 0, 0); radix_tree_tag_set(&root, 1, 0); radix_tree_for_each_tagged(slot, &root, &iter, 0, 0) {