mm/huge_memory: fix folio split stats counting

The "return <error code>" statements for error checks at the beginning of
__folio_split() skip necessary count_vm_event() and count_mthp_stat() at
the end of the function.  Fix these by replacing them with "ret = <error
code>; goto out;".

Link: https://lkml.kernel.org/r/20251126210618.1971206-5-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1a3273491cc5f76c11abfab6fd2f4e851eb2c52b..8db0d81fca406018335634b2bec969c5d5abc624 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3942,16 +3942,20 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
        VM_WARN_ON_ONCE_FOLIO(!folio_test_locked(folio), folio);
        VM_WARN_ON_ONCE_FOLIO(!folio_test_large(folio), folio);
 
-       if (folio != page_folio(split_at) || folio != page_folio(lock_at))
-               return -EINVAL;
+       if (folio != page_folio(split_at) || folio != page_folio(lock_at)) {
+               ret = -EINVAL;
+               goto out;
+       }
 
-       if (new_order >= old_order)
-               return -EINVAL;
+       if (new_order >= old_order) {
+               ret = -EINVAL;
+               goto out;
+       }
 
        ret = folio_check_splittable(folio, new_order, split_type);
        if (ret) {
                VM_WARN_ONCE(ret == -EINVAL, "Tried to split an unsplittable folio");
-               return ret;
+               goto out;
        }
 
        if (is_anon) {