Commit 3ece58a2 authored by Matthew Wilcox's avatar Matthew Wilcox

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: default avatarMatthew Wilcox <willy@infradead.org>
parent fd1b3cee
......@@ -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'
......
......@@ -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
*
......
......@@ -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;
......
......@@ -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) {
......
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