+ mm-swap-introduce-a-helper-for-retrieving-cluster-from-offset.patch added to mm-unstable branch

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

The patch titled
     Subject: mm, swap: introduce a helper for retrieving cluster from offset
has been added to the -mm mm-unstable branch.  Its filename is
     mm-swap-introduce-a-helper-for-retrieving-cluster-from-offset.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swap-introduce-a-helper-for-retrieving-cluster-from-offset.patch

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

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------------------------------------------------------
From: Kairui Song <kasong@tencent.com>
Subject: mm, swap: introduce a helper for retrieving cluster from offset
Date: Tue, 31 Dec 2024 01:46:19 +0800

It's a common operation to retrieve the cluster info from offset,
introduce a helper for this.

Link: https://lkml.kernel.org/r/20241230174621.61185-12-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Suggested-by: Chris Li <chrisl@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/swapfile.c |   14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

--- a/mm/swapfile.c~mm-swap-introduce-a-helper-for-retrieving-cluster-from-offset
+++ a/mm/swapfile.c
@@ -424,6 +424,12 @@ static inline unsigned int cluster_index
 	return ci - si->cluster_info;
 }
 
+static inline struct swap_cluster_info *offset_to_cluster(struct swap_info_struct *si,
+							  unsigned long offset)
+{
+	return &si->cluster_info[offset / SWAPFILE_CLUSTER];
+}
+
 static inline unsigned int cluster_offset(struct swap_info_struct *si,
 					  struct swap_cluster_info *ci)
 {
@@ -435,7 +441,7 @@ static inline struct swap_cluster_info *
 {
 	struct swap_cluster_info *ci;
 
-	ci = &si->cluster_info[offset / SWAPFILE_CLUSTER];
+	ci = offset_to_cluster(si, offset);
 	spin_lock(&ci->lock);
 
 	return ci;
@@ -1477,10 +1483,10 @@ static void swap_entry_range_free(struct
 	unsigned char *map_end = map + nr_pages;
 	struct swap_cluster_info *ci;
 
-	/* It should never free entries across different clusters */
-	VM_BUG_ON((offset / SWAPFILE_CLUSTER) != ((offset + nr_pages - 1) / SWAPFILE_CLUSTER));
-
 	ci = lock_cluster(si, offset);
+
+	/* It should never free entries across different clusters */
+	VM_BUG_ON(ci != offset_to_cluster(si, offset + nr_pages - 1));
 	VM_BUG_ON(cluster_is_free(ci));
 	VM_BUG_ON(ci->count < nr_pages);
 
_

Patches currently in -mm which might be from kasong@tencent.com are

mm-list_lru-fix-false-warning-of-negative-counter.patch
mm-madvise-fix-potential-workingset-node-list_lru-leaks.patch
mm-memcontrol-avoid-duplicated-memcg-enable-check.patch
mm-swap_cgroup-remove-swap_cgroup_cmpxchg.patch
mm-swap_cgroup-remove-global-swap-cgroup-lock.patch
mm-swap_cgroup-decouple-swap-cgroup-recording-and-clearing.patch
mm-swap-minor-clean-up-for-swap-entry-allocation.patch
mm-swap-fold-swap_info_get_cont-in-the-only-caller.patch
mm-swap-remove-old-allocation-path-for-hdd.patch
mm-swap-use-cluster-lock-for-hdd.patch
mm-swap-clean-up-device-availability-check.patch
mm-swap-clean-up-plist-removal-and-adding.patch
mm-swap-hold-a-reference-during-scan-and-cleanup-flag-usage.patch
mm-swap-use-an-enum-to-define-all-cluster-flags-and-wrap-flags-changes.patch
mm-swap-reduce-contention-on-device-lock.patch
mm-swap-simplify-percpu-cluster-updating.patch
mm-swap-introduce-a-helper-for-retrieving-cluster-from-offset.patch
mm-swap-use-a-global-swap-cluster-for-non-rotation-devices.patch
mm-swap_slots-remove-slot-cache-for-freeing-path.patch