[PATCH V2] mm/hugetlb: Make __NR_USED_SUBPAGE check conditional

[Anshuman Khandual <anshuman.khandual@arm.com>]

The HugeTLB order check against __NR_USED_SUBPAGE is required only when
HUGETLB_PAGE_OPTIMIZE_VMEMMAP is enabled. Hence BUG_ON() trigger should
happen only when applicable.

Cc: Muchun Song <muchun.song@linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
This patch applies on v6.13-rc1

Changes in V2:

- Fixed #ifdef with CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP per Oscar

Changes in V1:

https://lore.kernel.org/all/20241202090728.78935-1-anshuman.khandual@arm.com/

 mm/hugetlb.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ea2ed8e301ef..e6a5b21e3578 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4513,11 +4513,13 @@ void __init hugetlb_add_hstate(unsigned int order)
 	struct hstate *h;
 	unsigned long i;
 
-	if (size_to_hstate(PAGE_SIZE << order)) {
+	if (size_to_hstate(PAGE_SIZE << order))
 		return;
-	}
+
 	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
+#ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
 	BUG_ON(order < order_base_2(__NR_USED_SUBPAGE));
+#endif
 	h = &hstates[hugetlb_max_hstate++];
 	__mutex_init(&h->resize_lock, "resize mutex", &h->resize_key);
 	h->order = order;
-- 
2.30.2