+ mm-swap-enable-swap_entry_range_free-to-drop-any-kind-of-last-ref-fix.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: swap: add __maybe_unused attribute for swap_is_last_ref() and update it's comment
has been added to the -mm mm-new branch.  Its filename is
     mm-swap-enable-swap_entry_range_free-to-drop-any-kind-of-last-ref-fix.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swap-enable-swap_entry_range_free-to-drop-any-kind-of-last-ref-fix.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Kemeng Shi <shikemeng@huaweicloud.com>
Subject: mm: swap: add __maybe_unused attribute for swap_is_last_ref() and update it's comment
Date: Thu, 10 Apr 2025 23:39:08 +0800

Add __maybe_unused attribute for swap_is_last_ref ()to fix following build
warning:

mm/swapfile.c:1517:20: warning: function 'swap_is_last_ref' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    1517 | static inline bool swap_is_last_ref(unsigned char count)
         |                    ^~~~~~~~~~~~~~~~
   1 warning generated.

Besides, original comment for swap_entries_free() is placed before
swap_is_last_ref() which may introduce confusion.  Update comment to
address this.

Link: https://lkml.kernel.org/r/20250410153908.612984-1-shikemeng@huaweicloud.com
Fixes: 6bb001b6b64ec ("mm: swap: enable swap_entry_range_free() to drop any kind of last ref")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Suggested-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Tested-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/swapfile.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/mm/swapfile.c~mm-swap-enable-swap_entry_range_free-to-drop-any-kind-of-last-ref-fix
+++ a/mm/swapfile.c
@@ -1511,15 +1511,19 @@ fallback:
 }
 
 /*
- * Drop the last ref(1, SWAP_HAS_CACHE or SWAP_MAP_SHMEM) of swap entries,
- * caller have to ensure all entries belong to the same cgroup and cluster.
+ * Check if it's the last ref of swap entry in the freeing path.
+ * Qualified vlaue includes 1, SWAP_HAS_CACHE or SWAP_MAP_SHMEM.
  */
-static inline bool swap_is_last_ref(unsigned char count)
+static inline bool __maybe_unused swap_is_last_ref(unsigned char count)
 {
 	return (count == SWAP_HAS_CACHE) || (count == 1) ||
 	       (count == SWAP_MAP_SHMEM);
 }
 
+/*
+ * Drop the last ref of swap entries, caller have to ensure all entries
+ * belong to the same cgroup and cluster.
+ */
 static void swap_entries_free(struct swap_info_struct *si,
 			      struct swap_cluster_info *ci,
 			      swp_entry_t entry, unsigned int nr_pages)
_

Patches currently in -mm which might be from shikemeng@huaweicloud.com are

mm-swap-rename-__swap__free-to-swap__put.patch
mm-swap-enable-swap_entry_range_free-to-drop-any-kind-of-last-ref.patch
mm-swap-enable-swap_entry_range_free-to-drop-any-kind-of-last-ref-fix.patch
mm-swap-use-swap_entries_free-to-free-swap-entry-in-swap_entry_put_locked.patch
mm-swap-use-swap_entries_free-drop-last-ref-count-in-swap_entries_put_nr.patch
mm-swap-drop-last-swap_map_shmem-flag-in-batch-in-swap_entries_put_nr.patch
mm-swap-free-each-cluster-individually-in-swap_entries_put_map_nr.patch
mm-swap-factor-out-helper-to-drop-cache-of-entries-within-a-single-cluster.patch
mm-swap-replace-cluster_swap_free_nr-with-swap_entries_put_.patch