dax: Convert dax_layout_busy_page to XArray

[mirror_ubuntu-hirsute-kernel.git] / fs / dax.c

diff --git a/fs/dax.c b/fs/dax.c
index 8873e4b0bc988107d8450eeb0c7a9aa8f33490fb..28a51f2e8e50e03021c2815ed5cb3944859fb76a 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -722,11 +722,10 @@ restart:
  */
 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.
@@ -737,13 +736,9 @@ 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
@@ -755,43 +750,26 @@ 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 (WARN_ON_ONCE(!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;
-               }
-
-               /*
-                * We don't expect normal struct page entries to exist in our
-                * tree, but we keep these pagevec calls so that this code is
-                * consistent with the common pattern for handling pagevecs
-                * throughout the kernel.
-                */
-               pagevec_remove_exceptionals(&pvec);
-               pagevec_release(&pvec);
-               index++;
-
+       xas_lock_irq(&xas);
+       xas_for_each(&xas, entry, ULONG_MAX) {
+               if (WARN_ON_ONCE(!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);