From: Kairui Song Date: Tue, 17 Feb 2026 20:06:35 +0000 (+0800) Subject: mm, swap: no need to truncate the scan border X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=45711d446b743da099b7a795ce91ca581d5981a3;p=thirdparty%2Flinux.git mm, swap: no need to truncate the scan border swap_map had a static flexible size, so the last cluster won't be fully covered, hence the allocator needs to check the scan border to avoid OOB. But the swap table has a fixed-sized swap table for each cluster, and the slots beyond the device size are marked as bad slots. The allocator can simply scan all slots as usual, and any bad slots will be skipped. Link: https://lkml.kernel.org/r/20260218-swap-table-p3-v3-10-f4e34be021a7@tencent.com Signed-off-by: Kairui Song Acked-by: Chris Li Cc: Baoquan He Cc: Barry Song Cc: David Hildenbrand Cc: Johannes Weiner Cc: Kairui Song Cc: Kemeng Shi Cc: kernel test robot Cc: Lorenzo Stoakes Cc: Nhat Pham Signed-off-by: Andrew Morton --- diff --git a/mm/swap.h b/mm/swap.h index 0a91e21e92b14..cc410b94e91ad 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -85,7 +85,7 @@ static inline struct swap_cluster_info *__swap_offset_to_cluster( struct swap_info_struct *si, pgoff_t offset) { VM_WARN_ON_ONCE(percpu_ref_is_zero(&si->users)); /* race with swapoff */ - VM_WARN_ON_ONCE(offset >= si->max); + VM_WARN_ON_ONCE(offset >= roundup(si->max, SWAPFILE_CLUSTER)); return &si->cluster_info[offset / SWAPFILE_CLUSTER]; } diff --git a/mm/swapfile.c b/mm/swapfile.c index cf976ecae8a80..4442c90407642 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -945,8 +945,8 @@ static unsigned int alloc_swap_scan_cluster(struct swap_info_struct *si, { unsigned int next = SWAP_ENTRY_INVALID, found = SWAP_ENTRY_INVALID; unsigned long start = ALIGN_DOWN(offset, SWAPFILE_CLUSTER); - unsigned long end = min(start + SWAPFILE_CLUSTER, si->max); unsigned int order = likely(folio) ? folio_order(folio) : 0; + unsigned long end = start + SWAPFILE_CLUSTER; unsigned int nr_pages = 1 << order; bool need_reclaim, ret, usable;