[PATCH v3 3/6] mm: gup: move gup_must_unshare() and INTERNAL_GUP_FLAGS to gup.c

[Yeoreum Yun]

gup_must_unshare() and INTERNAL_GUP_FLAGS are used in gup.c only.
Move gup_must_unshare() and INTERNAL_GUP_FLAGS from internal.h to gup.c

Signed-off-by: Yeoreum Yun <yeoreum.yun@xxxxxxx>
---
 mm/gup.c      | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 mm/internal.h | 70 -----------------------------------------------------------
 2 files changed, 69 insertions(+), 70 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index 7f9348c633d58..bfe83ce1411d5 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -633,6 +633,71 @@ static struct page *no_page_table(struct vm_area_struct *vma,
 	return NULL;
 }
 
+/*
+ * Indicates for which pages that are write-protected in the page table,
+ * whether GUP has to trigger unsharing via FAULT_FLAG_UNSHARE such that the
+ * GUP pin will remain consistent with the pages mapped into the page tables
+ * of the MM.
+ *
+ * Temporary unmapping of PageAnonExclusive() pages or clearing of
+ * PageAnonExclusive() has to protect against concurrent GUP:
+ * * Ordinary GUP: Using the PT lock
+ * * GUP-fast and fork(): mm->write_protect_seq
+ * * GUP-fast and KSM or temporary unmapping (swap, migration): see
+ *    folio_try_share_anon_rmap_*()
+ *
+ * Must be called with the (sub)page that's actually referenced via the
+ * page table entry, which might not necessarily be the head page for a
+ * PTE-mapped THP.
+ *
+ * If the vma is NULL, we're coming from the GUP-fast path and might have
+ * to fallback to the slow path just to lookup the vma.
+ */
+static inline bool gup_must_unshare(struct vm_area_struct *vma,
+				    unsigned int flags, struct page *page)
+{
+	/*
+	 * FOLL_WRITE is implicitly handled correctly as the page table entry
+	 * has to be writable -- and if it references (part of) an anonymous
+	 * folio, that part is required to be marked exclusive.
+	 */
+	if ((flags & (FOLL_WRITE | FOLL_PIN)) != FOLL_PIN)
+		return false;
+	/*
+	 * Note: PageAnon(page) is stable until the page is actually getting
+	 * freed.
+	 */
+	if (!PageAnon(page)) {
+		/*
+		 * We only care about R/O long-term pining: R/O short-term
+		 * pinning does not have the semantics to observe successive
+		 * changes through the process page tables.
+		 */
+		if (!(flags & FOLL_LONGTERM))
+			return false;
+
+		/* We really need the vma ... */
+		if (!vma)
+			return true;
+
+		/*
+		 * ... because we only care about writable private ("COW")
+		 * mappings where we have to break COW early.
+		 */
+		return vma_is_cow_mapping(vma);
+	}
+
+	/* Paired with a memory barrier in folio_try_share_anon_rmap_*(). */
+	if (IS_ENABLED(CONFIG_HAVE_GUP_FAST))
+		smp_rmb();
+
+	/*
+	 * Note that KSM pages cannot be exclusive, and consequently,
+	 * cannot get pinned.
+	 */
+	return !PageAnonExclusive(page);
+}
+
 #ifdef CONFIG_PGTABLE_HAS_HUGE_LEAVES
 /* FOLL_FORCE can write to even unwritable PUDs in COW mappings. */
 static inline bool can_follow_write_pud(pud_t pud, struct page *page,
@@ -2503,6 +2568,10 @@ static long __gup_longterm_locked(struct mm_struct *mm,
 	return rc ? rc : nr_pinned_pages;
 }
 
+#define INTERNAL_GUP_FLAGS (FOLL_TOUCH | FOLL_TRIED | FOLL_REMOTE | FOLL_PIN | \
+			    FOLL_FAST_ONLY | FOLL_UNLOCKABLE | \
+			    FOLL_MADV_POPULATE)
+
 /*
  * Check that the given flags are valid for the exported gup/pup interface, and
  * update them with the required flags that the caller must have set.
diff --git a/mm/internal.h b/mm/internal.h
index 9b8864a8540aa..7a315c0a93f49 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1330,76 +1330,6 @@ enum {
 	FOLL_MADV_POPULATE = 1 << 22,
 };
 
-#define INTERNAL_GUP_FLAGS (FOLL_TOUCH | FOLL_TRIED | FOLL_REMOTE | FOLL_PIN | \
-			    FOLL_FAST_ONLY | FOLL_UNLOCKABLE | \
-			    FOLL_MADV_POPULATE)
-
-/*
- * Indicates for which pages that are write-protected in the page table,
- * whether GUP has to trigger unsharing via FAULT_FLAG_UNSHARE such that the
- * GUP pin will remain consistent with the pages mapped into the page tables
- * of the MM.
- *
- * Temporary unmapping of PageAnonExclusive() pages or clearing of
- * PageAnonExclusive() has to protect against concurrent GUP:
- * * Ordinary GUP: Using the PT lock
- * * GUP-fast and fork(): mm->write_protect_seq
- * * GUP-fast and KSM or temporary unmapping (swap, migration): see
- *    folio_try_share_anon_rmap_*()
- *
- * Must be called with the (sub)page that's actually referenced via the
- * page table entry, which might not necessarily be the head page for a
- * PTE-mapped THP.
- *
- * If the vma is NULL, we're coming from the GUP-fast path and might have
- * to fallback to the slow path just to lookup the vma.
- */
-static inline bool gup_must_unshare(struct vm_area_struct *vma,
-				    unsigned int flags, struct page *page)
-{
-	/*
-	 * FOLL_WRITE is implicitly handled correctly as the page table entry
-	 * has to be writable -- and if it references (part of) an anonymous
-	 * folio, that part is required to be marked exclusive.
-	 */
-	if ((flags & (FOLL_WRITE | FOLL_PIN)) != FOLL_PIN)
-		return false;
-	/*
-	 * Note: PageAnon(page) is stable until the page is actually getting
-	 * freed.
-	 */
-	if (!PageAnon(page)) {
-		/*
-		 * We only care about R/O long-term pining: R/O short-term
-		 * pinning does not have the semantics to observe successive
-		 * changes through the process page tables.
-		 */
-		if (!(flags & FOLL_LONGTERM))
-			return false;
-
-		/* We really need the vma ... */
-		if (!vma)
-			return true;
-
-		/*
-		 * ... because we only care about writable private ("COW")
-		 * mappings where we have to break COW early.
-		 */
-		return vma_is_cow_mapping(vma);
-	}
-
-	/* Paired with a memory barrier in folio_try_share_anon_rmap_*(). */
-	if (IS_ENABLED(CONFIG_HAVE_GUP_FAST))
-		smp_rmb();
-
-	/*
-	 * Note that KSM pages cannot be exclusive, and consequently,
-	 * cannot get pinned.
-	 */
-	return !PageAnonExclusive(page);
-}
-
-
 static inline bool vma_soft_dirty_enabled(struct vm_area_struct *vma)
 {
 	/*

-- 
2.43.0