[PATCH 38/39] mm/huge_memory: remove vma_is_special_huge()

[Lorenzo Stoakes (ARM)]

vma_is_special_huge() tests whether either the VMA_PFNMAP_BIT or
VMA_MIXEDMAP_BIT is set (i.e. whether the VMA is a kernel-owned mapping),
but with a DAX carve-out.

DAX however no longer sets VMA_MIXEDMAP_BIT, so this carve-out is no longer
required.

Therefore test for vma_is_kernel_owned() instead and also drop the
VMA_IO_BIT check, as it is now redundant since it is enforced that only
kernel-owned mappings can set this flag.

This also eliminates another overloaded use of 'special' within mm.

No functional change intended.

Signed-off-by: Lorenzo Stoakes (ARM) <ljs@xxxxxxxxxx>
---
 mm/huge_memory.c | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index cf6c50e531f5..1ec1cd970ce6 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -110,14 +110,6 @@ static inline bool file_thp_enabled(const struct vm_area_struct *vma)
 	return S_ISREG(inode->i_mode);
 }
 
-/* If returns true, we are unable to access the VMA's folios. */
-static bool vma_is_special_huge(const struct vm_area_struct *vma)
-{
-	if (vma_is_dax(vma))
-		return false;
-	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)
 {
@@ -192,7 +184,7 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
 	/* Check the intersection of requested and supported orders. */
 	if (vma_is_anonymous(vma))
 		supported_orders = THP_ORDERS_ALL_ANON;
-	else if (vma_is_dax(vma) || vma_is_special_huge(vma))
+	else if (vma_is_dax(vma) || vma_is_kernel_owned(vma))
 		supported_orders = THP_ORDERS_ALL_SPECIAL_DAX;
 	else
 		supported_orders = THP_ORDERS_ALL_FILE_DEFAULT;
@@ -3065,7 +3057,7 @@ int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma,
 	orig_pud = pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm);
 	arch_check_zapped_pud(vma, orig_pud);
 	tlb_remove_pud_tlb_entry(tlb, pud, addr);
-	if (vma_is_special_huge(vma)) {
+	if (vma_is_kernel_owned(vma)) {
 		spin_unlock(ptl);
 		/* No zero page support yet */
 	} else {
@@ -3221,7 +3213,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 		 */
 		if (arch_needs_pgtable_deposit())
 			zap_deposited_table(mm, pmd);
-		if (vma_is_special_huge(vma))
+		if (vma_is_kernel_owned(vma))
 			return;
 		if (unlikely(pmd_is_migration_entry(old_pmd))) {
 			const softleaf_t old_entry = softleaf_from_pmd(old_pmd);
@@ -4750,9 +4742,7 @@ static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma)
 {
 	if (vma_is_dax(vma))
 		return true;
-	if (vma_is_special_huge(vma))
-		return true;
-	if (vma_test(vma, VMA_IO_BIT))
+	if (vma_is_kernel_owned(vma))
 		return true;
 	if (vma_is_hugetlb(vma))
 		return true;

-- 
2.55.0