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Message-Id: <20180617020052.4759-28-willy@infradead.org>
Date: Sat, 16 Jun 2018 19:00:05 -0700
From: Matthew Wilcox <willy@...radead.org>
To: linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Matthew Wilcox <willy@...radead.org>, Jan Kara <jack@...e.cz>,
Jeff Layton <jlayton@...hat.com>,
Lukas Czerner <lczerner@...hat.com>,
Ross Zwisler <ross.zwisler@...ux.intel.com>,
Christoph Hellwig <hch@....de>,
Goldwyn Rodrigues <rgoldwyn@...e.com>,
Nicholas Piggin <npiggin@...il.com>,
Ryusuke Konishi <konishi.ryusuke@....ntt.co.jp>,
linux-nilfs@...r.kernel.org, Jaegeuk Kim <jaegeuk@...nel.org>,
Chao Yu <yuchao0@...wei.com>,
linux-f2fs-devel@...ts.sourceforge.net
Subject: [PATCH v14 27/74] 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 <willy@...radead.org>
---
.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 faffc0d5af4e..c1de31c6875e 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 4b6f685309fc..eefa0b099dd5 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 019c263bb6be..8a69613fcdf3 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 ace2543c3eda..9f9a3b280f56 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) {
--
2.17.1
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