mm/huge_memory: clean up after-split folio freeing in __folio_split

Replace free_folio_and_swap_cache() with an explicit folio_free_swap() and
folio_put() in the after-split loop.  free_folio_and_swap_cache() must
trylock it again and re-check folio_mapped() before freeing the swap cache
entries.  If the trylock loses a race, the entries are left behind even
though the folio reference is dropped.

The sub folios are still locked here, so just directly call
folio_free_swap() under the lock if it's unmapped, then unlock and drop
the reference.  This makes the swap cache freeing deterministic and the
reference drop explicit.

Link: https://lore.kernel.org/20260923-swap-thp-cleanup-v6-15-ba1b4ba72c6f@tencent.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nico Pache <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Youngjun Park <youngjun.park@lge.com>
Cc: Shivam Kalra <shivamkalra98@zohomail.in>
Cc: Kairui Song <ryncsn@gmail.com>

0 files changed, 0 insertions, 0 deletions