swapfile: convert __try_to_reclaim_swap() to use a folio

Saves five calls to compound_head().

Link: https://lkml.kernel.org/r/20220902194653.1739778-36-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 23cdbe8..e3e1bd3 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -132,27 +132,27 @@ static int __try_to_reclaim_swap(struct swap_info_struct *si,
                                 unsigned long offset, unsigned long flags)
 {
        swp_entry_t entry = swp_entry(si->type, offset);
-       struct page *page;
+       struct folio *folio;
        int ret = 0;
 
-       page = find_get_page(swap_address_space(entry), offset);
-       if (!page)
+       folio = filemap_get_folio(swap_address_space(entry), offset);
+       if (!folio)
                return 0;
        /*
         * When this function is called from scan_swap_map_slots() and it's
-        * called by vmscan.c at reclaiming pages. So, we hold a lock on a page,
+        * called by vmscan.c at reclaiming folios. So we hold a folio lock
         * here. We have to use trylock for avoiding deadlock. This is a special
-        * case and you should use try_to_free_swap() with explicit lock_page()
+        * case and you should use folio_free_swap() with explicit folio_lock()
         * in usual operations.
         */
-       if (trylock_page(page)) {
+       if (folio_trylock(folio)) {
                if ((flags & TTRS_ANYWAY) ||
-                   ((flags & TTRS_UNMAPPED) && !page_mapped(page)) ||
-                   ((flags & TTRS_FULL) && mem_cgroup_swap_full(page)))
-                       ret = try_to_free_swap(page);
-               unlock_page(page);
+                   ((flags & TTRS_UNMAPPED) && !folio_mapped(folio)) ||
+                   ((flags & TTRS_FULL) && mem_cgroup_swap_full(&folio->page)))
+                       ret = folio_free_swap(folio);
+               folio_unlock(folio);
        }
-       put_page(page);
+       folio_put(folio);
        return ret;
 }