Instead of using a pagevec, just use the XArray iterators. Add a
conditional rescheduling point which probably should have been there in
the original.
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
---
fs/dax.c | 57 +++++++++++++++++++++-----------------------------------
1 file changed, 21 insertions(+), 36 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 71181f4bb1d3..7b80b17cba50 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -697,11 +697,10 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
*/
struct page *dax_layout_busy_page(struct address_space *mapping)
{
- pgoff_t indices[PAGEVEC_SIZE];
+ XA_STATE(xas, &mapping->i_pages, 0);
+ void *entry;
+ unsigned int scanned = 0;
struct page *page = NULL;
- struct pagevec pvec;
- pgoff_t index, end;
- unsigned i;
/*
* In the 'limited' case get_user_pages() for dax is disabled.
@@ -712,13 +711,9 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
if (!dax_mapping(mapping) || !mapping_mapped(mapping))
return NULL;
- pagevec_init(&pvec);
- index = 0;
- end = -1;
-
/*
* If we race get_user_pages_fast() here either we'll see the
- * elevated page count in the pagevec_lookup and wait, or
+ * elevated page count in the iteration and wait, or
* get_user_pages_fast() will see that the page it took a reference
* against is no longer mapped in the page tables and bail to the
* get_user_pages() slow path. The slow path is protected by
@@ -730,36 +725,26 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
*/
unmap_mapping_range(mapping, 0, 0, 1);
- while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
- min(end - index, (pgoff_t)PAGEVEC_SIZE),
- indices)) {
- for (i = 0; i < pagevec_count(&pvec); i++) {
- struct page *pvec_ent = pvec.pages[i];
- void *entry;
-
- index = indices[i];
- if (index >= end)
- break;
-
- if (!xa_is_value(pvec_ent))
- continue;
-
- xa_lock_irq(&mapping->i_pages);
- entry = get_unlocked_mapping_entry(mapping, index, NULL);
- if (entry)
- page = dax_busy_page(entry);
- put_unlocked_mapping_entry(mapping, index, entry);
- xa_unlock_irq(&mapping->i_pages);
- if (page)
- break;
- }
- pagevec_remove_exceptionals(&pvec);
- pagevec_release(&pvec);
- index++;
-
+ xas_lock_irq(&xas);
+ xas_for_each(&xas, entry, ULONG_MAX) {
+ if (!xa_is_value(entry))
+ continue;
+ if (unlikely(dax_is_locked(entry)))
+ entry = get_unlocked_entry(&xas);
+ if (entry)
+ page = dax_busy_page(entry);
+ put_unlocked_entry(&xas, entry);
if (page)
break;
+ if (++scanned % XA_CHECK_SCHED)
+ continue;
+
+ xas_pause(&xas);
+ xas_unlock_irq(&xas);
+ cond_resched();
+ xas_lock_irq(&xas);
}
+ xas_unlock_irq(&xas);
return page;
}
EXPORT_SYMBOL_GPL(dax_layout_busy_page);
--
2.17.1
