[PATCH] mm/page_vma_mapped: guard check_pmd() with CONFIG_TRANSPARENT_HUGEPAGE

[Wei Yang]

The kernel test robot reported a build failure on the parisc architecture
when expanding HPAGE_PMD_NR in check_pmd().

   mm/page_vma_mapped.c:142:13: note: in expansion of macro 'HPAGE_PMD_NR'
     if ((pfn + HPAGE_PMD_NR - 1) < pvmw->pfn)
                ^~~~~~~~~~~~

The config [1] in report link shows neither TRANSPARENT_HUGEPAGE nor
HUGETLB_PAGE is defined. Then trigger the BUILD_BUG.

Fix it by define check_pmd() under CONFIG_TRANSPARENT_HUGEPAGE.

[1]: https://download.01.org/0day-ci/archive/20260624/202606240042.ffPsEXVc-lkp@xxxxxxxxx/config

Fixes: 2aff7a4755be ("mm: Convert page_vma_mapped_walk to work on PFNs")
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202606240042.ffPsEXVc-lkp@xxxxxxxxx/
---
 mm/page_vma_mapped.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 17dff8aab9f9..4aac94d9e8a9 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -136,6 +136,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw, unsigned long pte_nr)
 	return true;
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 /* Returns true if the two ranges overlap.  Careful to not overflow. */
 static bool check_pmd(unsigned long pfn, struct page_vma_mapped_walk *pvmw)
 {
@@ -145,6 +146,12 @@ static bool check_pmd(unsigned long pfn, struct page_vma_mapped_walk *pvmw)
 		return false;
 	return true;
 }
+#else
+static bool check_pmd(unsigned long pfn, struct page_vma_mapped_walk *pvmw)
+{
+	return false;
+}
+#endif
 
 static void step_forward(struct page_vma_mapped_walk *pvmw, unsigned long size)
 {
-- 
2.34.1