linux-kernel - [PATCH 2/4] mm, swap: rename helper for setup bad slots

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Message-Id: <20251007-swap-clean-after-swap-table-p1-v1-2-74860ef8ba74@tencent.com>
Date: Tue, 07 Oct 2025 04:02:34 +0800
From: Kairui Song <ryncsn@...il.com>
To: linux-mm@...ck.org
Cc: Andrew Morton <akpm@...ux-foundation.org>, 
 Kemeng Shi <shikemeng@...weicloud.com>, Kairui Song <kasong@...cent.com>, 
 Nhat Pham <nphamcs@...il.com>, Baoquan He <bhe@...hat.com>, 
 Barry Song <baohua@...nel.org>, Chris Li <chrisl@...nel.org>, 
 Baolin Wang <baolin.wang@...ux.alibaba.com>, 
 David Hildenbrand <david@...hat.com>, 
 "Matthew Wilcox (Oracle)" <willy@...radead.org>, 
 Ying Huang <ying.huang@...ux.alibaba.com>, Kairui Song <ryncsn@...il.com>, 
 linux-kernel@...r.kernel.org
Subject: [PATCH 2/4] mm, swap: rename helper for setup bad slots

From: Kairui Song <kasong@...cent.com>

The name inc_cluster_info_page is very confusing, as this helper is only
used during swapon to mark bad slots. Rename it properly and turn the
VM_BUG_ON in it into WARN_ON to expose more potential issues. Swapon is
a cold path, so adding more checks should be a good idea.

No feature change except new WARN_ON.

Signed-off-by: Kairui Song <kasong@...cent.com>
---
 mm/swapfile.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 0d1924f6f495..732e07c70ce9 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -751,14 +751,14 @@ static void relocate_cluster(struct swap_info_struct *si,
 }
 
 /*
- * The cluster corresponding to page_nr will be used. The cluster will not be
- * added to free cluster list and its usage counter will be increased by 1.
- * Only used for initialization.
+ * The cluster corresponding to @offset will be accounted as having one bad
+ * slot. The cluster will not be added to the free cluster list, and its
+ * usage counter will be increased by 1. Only used for initialization.
  */
-static int inc_cluster_info_page(struct swap_info_struct *si,
-	struct swap_cluster_info *cluster_info, unsigned long page_nr)
+static int swap_cluster_setup_bad_slot(struct swap_cluster_info *cluster_info,
+				       unsigned long offset)
 {
-	unsigned long idx = page_nr / SWAPFILE_CLUSTER;
+	unsigned long idx = offset / SWAPFILE_CLUSTER;
 	struct swap_table *table;
 	struct swap_cluster_info *ci;
 
@@ -772,8 +772,8 @@ static int inc_cluster_info_page(struct swap_info_struct *si,
 
 	ci->count++;
 
-	VM_BUG_ON(ci->count > SWAPFILE_CLUSTER);
-	VM_BUG_ON(ci->flags);
+	WARN_ON(ci->count > SWAPFILE_CLUSTER);
+	WARN_ON(ci->flags);
 
 	return 0;
 }
@@ -3396,7 +3396,7 @@ static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si,
 	 * See setup_swap_map(): header page, bad pages,
 	 * and the EOF part of the last cluster.
 	 */
-	err = inc_cluster_info_page(si, cluster_info, 0);
+	err = swap_cluster_setup_bad_slot(cluster_info, 0);
 	if (err)
 		goto err;
 	for (i = 0; i < swap_header->info.nr_badpages; i++) {
@@ -3404,12 +3404,12 @@ static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si,
 
 		if (page_nr >= maxpages)
 			continue;
-		err = inc_cluster_info_page(si, cluster_info, page_nr);
+		err = swap_cluster_setup_bad_slot(cluster_info, page_nr);
 		if (err)
 			goto err;
 	}
 	for (i = maxpages; i < round_up(maxpages, SWAPFILE_CLUSTER); i++) {
-		err = inc_cluster_info_page(si, cluster_info, i);
+		err = swap_cluster_setup_bad_slot(cluster_info, i);
 		if (err)
 			goto err;
 	}

-- 
2.51.0