[PATCH 02/12] mm: khugepaged: drop the hugepage_madvise()

[Baolin Wang]

After commit 2fd4e7693674 ("mm: fix incorrect vm_flags usage when checking
allowable orders for tmpfs"), hugepage_madvise() no longer calls any
khugepaged related functions and only updates the VMA flags. So remove this
helper and update the VMA flags directly in madvise_update_vma(), which
simplifies the code.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
 include/linux/huge_mm.h |  8 --------
 mm/khugepaged.c         | 22 ----------------------
 mm/madvise.c            |  8 +++++---
 3 files changed, 5 insertions(+), 33 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 8ca0fa3be2ac..334c387ad997 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -508,8 +508,6 @@ change_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			__split_huge_pud(__vma, __pud, __address);	\
 	}  while (0)
 
-int hugepage_madvise(struct vm_area_struct *vma, vm_flags_t *vm_flags,
-		     int advice);
 void vma_adjust_trans_huge(struct vm_area_struct *vma, unsigned long start,
 			   unsigned long end, struct vm_area_struct *next);
 spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma);
@@ -707,12 +705,6 @@ static inline bool unmap_huge_pmd_locked(struct vm_area_struct *vma,
 #define split_huge_pud(__vma, __pmd, __address)	\
 	do { } while (0)
 
-static inline int hugepage_madvise(struct vm_area_struct *vma,
-				   vm_flags_t *vm_flags, int advice)
-{
-	return -EINVAL;
-}
-
 static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
 					 unsigned long start,
 					 unsigned long end,
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 21d75f5b4b4d..f81ecaaa4890 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -380,28 +380,6 @@ static unsigned int collapse_max_ptes_swap(struct collapse_control *cc,
 	return cc->policy.max_ptes_swap;
 }
 
-int hugepage_madvise(struct vm_area_struct *vma,
-		     vm_flags_t *vm_flags, int advice)
-{
-	switch (advice) {
-	case MADV_HUGEPAGE:
-		*vm_flags &= ~VM_NOHUGEPAGE;
-		*vm_flags |= VM_HUGEPAGE;
-		break;
-	case MADV_NOHUGEPAGE:
-		*vm_flags &= ~VM_HUGEPAGE;
-		*vm_flags |= VM_NOHUGEPAGE;
-		/*
-		 * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning
-		 * this vma even if we leave the mm registered in khugepaged if
-		 * it got registered before VM_NOHUGEPAGE was set.
-		 */
-		break;
-	}
-
-	return 0;
-}
-
 int __init khugepaged_init(void)
 {
 	mm_slot_cache = KMEM_CACHE(mm_slot, 0);
diff --git a/mm/madvise.c b/mm/madvise.c
index eb491fa88325..4150f6a8cf64 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1598,10 +1598,12 @@ static int madvise_vma_behavior(struct madvise_behavior *madv_behavior)
 			goto out;
 		break;
 	case MADV_HUGEPAGE:
+		new_flags &= ~VM_NOHUGEPAGE;
+		new_flags |= VM_HUGEPAGE;
+		break;
 	case MADV_NOHUGEPAGE:
-		error = hugepage_madvise(vma, &new_flags, behavior);
-		if (error)
-			goto out;
+		new_flags &= ~VM_HUGEPAGE;
+		new_flags |= VM_NOHUGEPAGE;
 		break;
 	case __MADV_SET_ANON_VMA_NAME:
 		/* Only anonymous mappings can be named */
-- 
2.47.3