[PATCH 10/13] mm/vma: convert miscellaneous uses of VMA flags in core mm

[Lorenzo Stoakes <ljs@kernel.org>]

Update various uses of legacy flags in vma.c and mmap.c to the new
vma_flags_t type, updating comments alongside them to be consistent.

Also update __install_special_mapping() to rearrange things slightly to
accommodate the changes.

Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
---
 mm/mmap.c | 39 +++++++++++++++++++++------------------
 mm/vma.c  | 16 ++++++++++------
 2 files changed, 31 insertions(+), 24 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index e834ec9273e3..a8546c9250a0 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -557,8 +557,8 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
 	}
 
 	/*
-	 * Set 'VM_NORESERVE' if we should not account for the
-	 * memory use of this mapping.
+	 * Set VMA_NORESERVE_BIT if we should not account for the memory use
+	 * of this mapping.
 	 */
 	if (flags & MAP_NORESERVE) {
 		/* We honor MAP_NORESERVE if allowed to overcommit */
@@ -985,7 +985,7 @@ struct vm_area_struct *find_extend_vma_locked(struct mm_struct *mm, unsigned lon
 		return NULL;
 	if (expand_stack_locked(prev, addr))
 		return NULL;
-	if (prev->vm_flags & VM_LOCKED)
+	if (vma_test(prev, VMA_LOCKED_BIT))
 		populate_vma_page_range(prev, addr, prev->vm_end, NULL);
 	return prev;
 }
@@ -1009,7 +1009,7 @@ struct vm_area_struct *find_extend_vma_locked(struct mm_struct *mm, unsigned lon
 	start = vma->vm_start;
 	if (expand_stack_locked(vma, addr))
 		return NULL;
-	if (vma->vm_flags & VM_LOCKED)
+	if (vma_test(vma, VMA_LOCKED_BIT))
 		populate_vma_page_range(vma, addr, start, NULL);
 	return vma;
 }
@@ -1134,18 +1134,18 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
 	 */
 	vma = vma_lookup(mm, start);
 
-	if (!vma || !(vma->vm_flags & VM_SHARED)) {
+	if (!vma || !vma_test(vma, VMA_SHARED_BIT)) {
 		mmap_read_unlock(mm);
 		return -EINVAL;
 	}
 
-	prot |= vma->vm_flags & VM_READ ? PROT_READ : 0;
-	prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0;
-	prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0;
+	prot |= vma_test(vma, VMA_READ_BIT) ? PROT_READ : 0;
+	prot |= vma_test(vma, VMA_WRITE_BIT) ? PROT_WRITE : 0;
+	prot |= vma_test(vma, VMA_EXEC_BIT) ? PROT_EXEC : 0;
 
 	flags &= MAP_NONBLOCK;
 	flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
-	if (vma->vm_flags & VM_LOCKED)
+	if (vma_test(vma, VMA_LOCKED_BIT))
 		flags |= MAP_LOCKED;
 
 	/* Save vm_flags used to calculate prot and flags, and recheck later. */
@@ -1271,7 +1271,7 @@ unsigned long tear_down_vmas(struct mm_struct *mm, struct vma_iterator *vmi,
 	mmap_assert_write_locked(mm);
 	vma_iter_set(vmi, vma->vm_end);
 	do {
-		if (vma->vm_flags & VM_ACCOUNT)
+		if (vma_test(vma, VMA_ACCOUNT_BIT))
 			nr_accounted += vma_pages(vma);
 		vma_mark_detached(vma);
 		remove_vma(vma);
@@ -1420,7 +1420,7 @@ static int special_mapping_split(struct vm_area_struct *vma, unsigned long addr)
 {
 	/*
 	 * Forbid splitting special mappings - kernel has expectations over
-	 * the number of pages in mapping. Together with VM_DONTEXPAND
+	 * the number of pages in mapping. Together with VMA_DONTEXPAND_BIT
 	 * the size of vma should stay the same over the special mapping's
 	 * lifetime.
 	 */
@@ -1692,7 +1692,7 @@ bool mmap_read_lock_maybe_expand(struct mm_struct *mm,
 		return true;
 	}
 
-	if (!(new_vma->vm_flags & VM_GROWSDOWN))
+	if (!vma_test(new_vma, VMA_GROWSDOWN_BIT))
 		return false;
 
 	mmap_write_lock(mm);
@@ -1742,7 +1742,7 @@ __latent_entropy int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
 		retval = vma_start_write_killable(mpnt);
 		if (retval < 0)
 			goto loop_out;
-		if (mpnt->vm_flags & VM_DONTCOPY) {
+		if (vma_test(mpnt, VMA_DONTCOPY_BIT)) {
 			retval = vma_iter_clear_gfp(&vmi, mpnt->vm_start,
 						    mpnt->vm_end, GFP_KERNEL);
 			if (retval)
@@ -1752,7 +1752,7 @@ __latent_entropy int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
 			continue;
 		}
 		charge = 0;
-		if (mpnt->vm_flags & VM_ACCOUNT) {
+		if (vma_test(mpnt, VMA_ACCOUNT_BIT)) {
 			unsigned long len = vma_pages(mpnt);
 
 			if (security_vm_enough_memory_mm(oldmm, len)) /* sic */
@@ -1770,16 +1770,19 @@ __latent_entropy int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
 		retval = dup_userfaultfd(tmp, &uf);
 		if (retval)
 			goto fail_nomem_anon_vma_fork;
-		if (tmp->vm_flags & VM_WIPEONFORK) {
+
+		if (vma_test(tmp, VMA_WIPEONFORK_BIT)) {
 			/*
-			 * VM_WIPEONFORK gets a clean slate in the child.
+			 * VMA_WIPEONFORK_BIT gets a clean slate in the child.
 			 * Don't prepare anon_vma until fault since we don't
 			 * copy page for current vma.
 			 */
 			tmp->anon_vma = NULL;
 		} else if (anon_vma_fork(tmp, mpnt))
 			goto fail_nomem_anon_vma_fork;
-		vm_flags_clear(tmp, VM_LOCKED_MASK);
+
+		vma_start_write(tmp);
+		vma_clear_flags_mask(tmp, VMA_LOCKED_MASK);
 		/*
 		 * Copy/update hugetlb private vma information.
 		 */
@@ -1812,7 +1815,7 @@ __latent_entropy int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
 			i_mmap_unlock_write(mapping);
 		}
 
-		if (!(tmp->vm_flags & VM_WIPEONFORK))
+		if (!vma_test(tmp, VMA_WIPEONFORK_BIT))
 			retval = copy_page_range(tmp, mpnt);
 
 		if (retval) {
diff --git a/mm/vma.c b/mm/vma.c
index b81c05e67a61..ab2ef0f04420 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -3417,23 +3417,27 @@ struct vm_area_struct *__install_special_mapping(
 	vm_flags_t vm_flags, void *priv,
 	const struct vm_operations_struct *ops)
 {
-	int ret;
+	vma_flags_t vma_flags = legacy_to_vma_flags(vm_flags);
 	struct vm_area_struct *vma;
+	int ret;
 
 	vma = vm_area_alloc(mm);
-	if (unlikely(vma == NULL))
+	if (unlikely(!vma))
 		return ERR_PTR(-ENOMEM);
 
-	vma_set_range(vma, addr, addr + len, 0);
-	vm_flags |= vma_flags_to_legacy(mm->def_vma_flags) | VM_DONTEXPAND;
+	vma_flags_set_mask(&vma_flags, mm->def_vma_flags);
+	vma_flags_set(&vma_flags, VMA_DONTEXPAND_BIT);
 	if (pgtable_supports_soft_dirty())
-		vm_flags |= VM_SOFTDIRTY;
-	vm_flags_init(vma, vm_flags & ~VM_LOCKED_MASK);
+		vma_flags_set(&vma_flags, VMA_SOFTDIRTY_BIT);
+	vma_flags_clear_mask(&vma_flags, VMA_LOCKED_MASK);
+	vma->flags = vma_flags;
 	vma->vm_page_prot = vma_get_page_prot(vma);
 
 	vma->vm_ops = ops;
 	vma->vm_private_data = priv;
 
+	vma_set_range(vma, addr, addr + len, 0);
+
 	ret = insert_vm_struct(mm, vma);
 	if (ret)
 		goto out;
-- 
2.54.0