mm/hmm: move pmd_to_hmm_pfn_flags() to the respective #ifdeffery

When pmd_to_hmm_pfn_flags() is unused, it prevents kernel builds with
clang, `make W=1` and CONFIG_TRANSPARENT_HUGEPAGE=n:

  mm/hmm.c:186:29: warning: unused function 'pmd_to_hmm_pfn_flags' [-Wunused-function]

Fix this by moving the function to the respective existing ifdeffery
for its the only user.

See also:

  6863f5643dd7 ("kbuild: allow Clang to find unused static inline functions for W=1 build")

Link: https://lkml.kernel.org/r/20250710082403.664093-1-andriy.shevchenko@linux.intel.com
Fixes: 992de9a8b751 ("mm/hmm: allow to mirror vma of a file on a DAX backed filesystem")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/hmm.c b/mm/hmm.c
index f2415b4b2cdd3b10b6e53c21fb075af94ddcac4b..d545e24949949f4c1f057673799912418876d277 100644 (file)
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -183,6 +183,7 @@ static inline unsigned long hmm_pfn_flags_order(unsigned long order)
        return order << HMM_PFN_ORDER_SHIFT;
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static inline unsigned long pmd_to_hmm_pfn_flags(struct hmm_range *range,
                                                 pmd_t pmd)
 {
@@ -193,7 +194,6 @@ static inline unsigned long pmd_to_hmm_pfn_flags(struct hmm_range *range,
               hmm_pfn_flags_order(PMD_SHIFT - PAGE_SHIFT);
 }
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
                              unsigned long end, unsigned long hmm_pfns[],
                              pmd_t pmd)