1 files changed, 64 insertions, 22 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index afbb5974bd22..1e5d68acf62a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -92,7 +92,7 @@ unsigned long huge_anon_orders_madvise __read_mostly;
 unsigned long huge_anon_orders_inherit __read_mostly;
 static bool anon_orders_configured __initdata;
 
-static inline bool file_thp_enabled(struct vm_area_struct *vma)
+static inline bool file_thp_enabled(const struct vm_area_struct *vma)
 {
 	struct inode *inode;
 
@@ -118,6 +118,67 @@ static bool vma_is_special_huge(const struct vm_area_struct *vma)
 	return vma_test_any(vma, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT);
 }
 
+static bool vma_file_bypass_thp_tuneables(const struct vm_area_struct *vma,
+		enum tva_type type)
+{
+	const bool has_huge_fault = vma->vm_ops->huge_fault;
+
+	/* MADV_COLLAPSE ignores tuneables. */
+	if (type == TVA_FORCED_COLLAPSE)
+		return true;
+	/* Huge PFN mappings are uncompactable so the policy doesn't apply. */
+	if (vma_test(vma, VMA_PFNMAP_BIT) && has_huge_fault)
+		return true;
+	return false;
+}
+
+static bool vma_file_allow_thp_tuneables(vm_flags_t vm_flags)
+{
+	/* THP=always? */
+	if (hugepage_global_always())
+		return true;
+	/* THP=madvise and marked MADV_HUGEPAGE? */
+	if (hugepage_global_enabled() && (vm_flags & VM_HUGEPAGE))
+		return true;
+	return false;
+}
+
+static bool vma_file_check_thp_tuneables(const struct vm_area_struct *vma,
+		vm_flags_t vm_flags, enum tva_type type)
+{
+	return vma_file_bypass_thp_tuneables(vma, type) ||
+		vma_file_allow_thp_tuneables(vm_flags);
+}
+
+static bool vma_can_map_huge_file(const struct vm_area_struct *vma,
+		vm_flags_t vm_flags, enum tva_type type)
+{
+	const bool has_huge_fault = vma->vm_ops->huge_fault;
+
+	/*
+	 * Enforce THP collapse requirements as necessary. Anonymous vmas
+	 * were already handled in thp_vma_allowable_orders().
+	 */
+	if (!vma_file_check_thp_tuneables(vma, vm_flags, type))
+		return false;
+
+	switch (type) {
+	case TVA_PAGEFAULT:
+		/*
+		 * Trust that ->huge_fault() handlers know what they are doing
+		 * in fault path.
+		 */
+		return has_huge_fault;
+	case TVA_SMAPS:
+		if (has_huge_fault)
+			return true;
+		fallthrough;
+	default:
+		/* Only regular file is valid in collapse path. */
+		return file_thp_enabled(vma);
+	}
+}
+
 unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
 					 vm_flags_t vm_flags,
 					 enum tva_type type,
@@ -190,27 +251,8 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
 						   vma, vma_start_pgoff(vma), 0,
 						   forced_collapse);
 
-	if (!vma_is_anonymous(vma)) {
-		/*
-		 * Enforce THP collapse requirements as necessary. Anonymous vmas
-		 * were already handled in thp_vma_allowable_orders().
-		 */
-		if (!forced_collapse &&
-		    (!hugepage_global_enabled() || (!(vm_flags & VM_HUGEPAGE) &&
-						    !hugepage_global_always())))
-			return 0;
-
-		/*
-		 * Trust that ->huge_fault() handlers know what they are doing
-		 * in fault path.
-		 */
-		if (((in_pf || smaps)) && vma->vm_ops->huge_fault)
-			return orders;
-		/* Only regular file is valid in collapse path */
-		if (((!in_pf || smaps)) && file_thp_enabled(vma))
-			return orders;
-		return 0;
-	}
+	if (!vma_is_anonymous(vma))
+		return vma_can_map_huge_file(vma, vm_flags, type) ? orders : 0;
 
 	if (vma_is_temporary_stack(vma))
 		return 0;