mm: swap: replace cluster_swap_free_nr() with swap_entries_put_[map/cache]()

Replace cluster_swap_free_nr() with swap_entries_put_[map/cache]() to
remove repeat code and leverage batch-remove for entries with last flag.
After removing cluster_swap_free_nr, only functions with "_nr" suffix
could free entries spanning cross clusters.  Add corresponding description
in comment of swap_entries_put_map_nr() as is first function with "_nr"
suffix and have a non-suffix variant function swap_entries_put_map().

Link: https://lkml.kernel.org/r/20250325162528.68385-9-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 953dcd99006edae697b57a76bd8d7d177e8b560b..b86637cfb17a8923288a3f0801aca0e8f3c596c9 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1520,6 +1520,11 @@ locked_fallback:
 
 }
 
+/*
+ * Only functions with "_nr" suffix are able to free entries spanning
+ * cross multi clusters, so ensure the range is within a single cluster
+ * when freeing entries with functions without "_nr" suffix.
+ */
 static bool swap_entries_put_map_nr(struct swap_info_struct *si,
                                    swp_entry_t entry, int nr)
 {
@@ -1581,21 +1586,6 @@ static void swap_entries_free(struct swap_info_struct *si,
                partial_free_cluster(si, ci);
 }
 
-static void cluster_swap_free_nr(struct swap_info_struct *si,
-               unsigned long offset, int nr_pages,
-               unsigned char usage)
-{
-       struct swap_cluster_info *ci;
-       unsigned long end = offset + nr_pages;
-
-       ci = lock_cluster(si, offset);
-       do {
-               swap_entry_put_locked(si, ci, swp_entry(si->type, offset),
-                                     usage);
-       } while (++offset < end);
-       unlock_cluster(ci);
-}
-
 /*
  * Caller has made sure that the swap device corresponding to entry
  * is still around or has not been recycled.
@@ -1612,7 +1602,7 @@ void swap_free_nr(swp_entry_t entry, int nr_pages)
 
        while (nr_pages) {
                nr = min_t(int, nr_pages, SWAPFILE_CLUSTER - offset % SWAPFILE_CLUSTER);
-               cluster_swap_free_nr(sis, offset, nr, 1);
+               swap_entries_put_map(sis, swp_entry(sis->type, offset), nr);
                offset += nr;
                nr_pages -= nr;
        }
@@ -3658,11 +3648,13 @@ int swapcache_prepare(swp_entry_t entry, int nr)
        return __swap_duplicate(entry, SWAP_HAS_CACHE, nr);
 }
 
+/*
+ * Caller should ensure entries belong to the same folio so
+ * the entries won't span cross cluster boundary.
+ */
 void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr)
 {
-       unsigned long offset = swp_offset(entry);
-
-       cluster_swap_free_nr(si, offset, nr, SWAP_HAS_CACHE);
+       swap_entries_put_cache(si, entry, nr);
 }
 
 struct swap_info_struct *swp_swap_info(swp_entry_t entry)