mm, swap: rename helper for setup bad slots

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.

Link: https://lkml.kernel.org/r/20251007-swap-clean-after-swap-table-p1-v1-2-74860ef8ba74@tencent.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Chris Li <chrisl@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: 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 0d1924f6f49584268416cddd01a5430739e5d62c..732e07c70ce9e52ba2fefca346f86afa89072cfa 100644 (file)
--- 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;
        }