[PATCH 3/8] mm: Add pmd_folio()

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

Convert directly from a pmd to a folio without going through another
representation first.  For now this is just a slightly shorter way to
write it, but it might end up being more efficient later.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/pgtable.h | 2 ++
 mm/huge_memory.c        | 6 +++---
 mm/madvise.c            | 2 +-
 mm/mempolicy.c          | 2 +-
 mm/mlock.c              | 2 +-
 mm/userfaultfd.c        | 2 +-
 6 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 600e17d03659..09c85c7bf9c2 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -50,6 +50,8 @@
 #define pmd_pgtable(pmd) pmd_page(pmd)
 #endif
 
+#define pmd_folio(pmd) page_folio(pmd_page(pmd))
+
 /*
  * A page table page can be thought of an array like this: pXd_t[PTRS_PER_PxD]
  *
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 78f9132daa52..8ee09bfdfdb7 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1816,7 +1816,7 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		goto out;
 	}
 
-	folio = pfn_folio(pmd_pfn(orig_pmd));
+	folio = pmd_folio(orig_pmd);
 	/*
 	 * If other processes are mapping this folio, we couldn't discard
 	 * the folio unless they all do MADV_FREE so let's skip the folio.
@@ -2086,7 +2086,7 @@ int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		if (pmd_protnone(*pmd))
 			goto unlock;
 
-		folio = page_folio(pmd_page(*pmd));
+		folio = pmd_folio(*pmd);
 		toptier = node_is_toptier(folio_nid(folio));
 		/*
 		 * Skip scanning top tier node if normal numa
@@ -2663,7 +2663,7 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 		 * It's safe to call pmd_page when folio is set because it's
 		 * guaranteed that pmd is present.
 		 */
-		if (folio && folio != page_folio(pmd_page(*pmd)))
+		if (folio && folio != pmd_folio(*pmd))
 			goto out;
 		__split_huge_pmd_locked(vma, pmd, range.start, freeze);
 	}
diff --git a/mm/madvise.c b/mm/madvise.c
index 7625830d6ae9..1f77a51baaac 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -363,7 +363,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
 			goto huge_unlock;
 		}
 
-		folio = pfn_folio(pmd_pfn(orig_pmd));
+		folio = pmd_folio(orig_pmd);
 
 		/* Do not interfere with other mappings of this folio */
 		if (folio_likely_mapped_shared(folio))
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 6e7069ecf713..4f5d0923af8f 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -509,7 +509,7 @@ static void queue_folios_pmd(pmd_t *pmd, struct mm_walk *walk)
 		qp->nr_failed++;
 		return;
 	}
-	folio = pfn_folio(pmd_pfn(*pmd));
+	folio = pmd_folio(*pmd);
 	if (is_huge_zero_folio(folio)) {
 		walk->action = ACTION_CONTINUE;
 		return;
diff --git a/mm/mlock.c b/mm/mlock.c
index 1ed2f2ab37cd..30b51cdea89d 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -378,7 +378,7 @@ static int mlock_pte_range(pmd_t *pmd, unsigned long addr,
 			goto out;
 		if (is_huge_zero_pmd(*pmd))
 			goto out;
-		folio = page_folio(pmd_page(*pmd));
+		folio = pmd_folio(*pmd);
 		if (vma->vm_flags & VM_LOCKED)
 			mlock_folio(folio);
 		else
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 4f1a392fe84f..f6267afe65d1 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -1697,7 +1697,7 @@ ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start,
 			/* Check if we can move the pmd without splitting it. */
 			if (move_splits_huge_pmd(dst_addr, src_addr, src_start + len) ||
 			    !pmd_none(dst_pmdval)) {
-				struct folio *folio = pfn_folio(pmd_pfn(*src_pmd));
+				struct folio *folio = pmd_folio(*src_pmd);
 
 				if (!folio || (!is_huge_zero_folio(folio) &&
 					       !PageAnonExclusive(&folio->page))) {
-- 
2.43.0