[PATCH 25/43] mm: Switch vma_merge(), split_vma(), and __split_vma to vma iterator

[Liam Howlett <liam.howlett@oracle.com>]

From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>

Drop the vmi_* functions and transition all users to use the vma
iterator directly.

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
 fs/userfaultfd.c   | 14 ++++----
 include/linux/mm.h | 16 +++-------
 mm/madvise.c       |  6 ++--
 mm/mempolicy.c     |  6 ++--
 mm/mlock.c         |  6 ++--
 mm/mmap.c          | 79 +++++++++++++---------------------------------
 mm/mprotect.c      |  6 ++--
 mm/mremap.c        |  2 +-
 8 files changed, 47 insertions(+), 88 deletions(-)

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index b3249388696a..e60f86d6b91c 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -883,7 +883,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
 			continue;
 		}
 		new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS;
-		prev = vmi_vma_merge(&vmi, mm, prev, vma->vm_start, vma->vm_end,
+		prev = vma_merge(&vmi, mm, prev, vma->vm_start, vma->vm_end,
 				 new_flags, vma->anon_vma,
 				 vma->vm_file, vma->vm_pgoff,
 				 vma_policy(vma),
@@ -1426,7 +1426,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
 		vma_end = min(end, vma->vm_end);
 
 		new_flags = (vma->vm_flags & ~__VM_UFFD_FLAGS) | vm_flags;
-		prev = vmi_vma_merge(&vmi, mm, prev, start, vma_end, new_flags,
+		prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags,
 				 vma->anon_vma, vma->vm_file, vma->vm_pgoff,
 				 vma_policy(vma),
 				 ((struct vm_userfaultfd_ctx){ ctx }),
@@ -1437,12 +1437,12 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
 			goto next;
 		}
 		if (vma->vm_start < start) {
-			ret = vmi_split_vma(&vmi, mm, vma, start, 1);
+			ret = split_vma(&vmi, vma, start, 1);
 			if (ret)
 				break;
 		}
 		if (vma->vm_end > end) {
-			ret = vmi_split_vma(&vmi, mm, vma, end, 0);
+			ret = split_vma(&vmi, vma, end, 0);
 			if (ret)
 				break;
 		}
@@ -1606,7 +1606,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
 			uffd_wp_range(mm, vma, start, vma_end - start, false);
 
 		new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS;
-		prev = vmi_vma_merge(&vmi, mm, prev, start, vma_end, new_flags,
+		prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags,
 				 vma->anon_vma, vma->vm_file, vma->vm_pgoff,
 				 vma_policy(vma),
 				 NULL_VM_UFFD_CTX, anon_vma_name(vma));
@@ -1615,13 +1615,13 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
 			goto next;
 		}
 		if (vma->vm_start < start) {
-			ret = vmi_split_vma(&vmi, mm, vma, start, 1);
+			ret = split_vma(&vmi, vma, start, 1);
 			if (ret)
 				break;
 		}
 		if (vma->vm_end > end) {
 			vma_iter_set(&vmi, vma->vm_end);
-			ret = vmi_split_vma(&vmi, mm, vma, end, 0);
+			ret = split_vma(&vmi, vma, end, 0);
 			if (ret)
 				break;
 		}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 17623a774e02..2fa8aae4c4f2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2700,22 +2700,16 @@ static inline int vma_adjust(struct vm_area_struct *vma, unsigned long start,
 {
 	return __vma_adjust(vma, start, end, pgoff, insert, NULL);
 }
-extern struct vm_area_struct *vma_merge(struct mm_struct *,
-	struct vm_area_struct *prev, unsigned long addr, unsigned long end,
-	unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
-	struct mempolicy *, struct vm_userfaultfd_ctx, struct anon_vma_name *);
-extern struct vm_area_struct *vmi_vma_merge(struct vma_iterator *vmi,
+extern struct vm_area_struct *vma_merge(struct vma_iterator *vmi,
 	struct mm_struct *, struct vm_area_struct *prev, unsigned long addr,
 	unsigned long end, unsigned long vm_flags, struct anon_vma *,
 	struct file *, pgoff_t, struct mempolicy *, struct vm_userfaultfd_ctx,
 	struct anon_vma_name *);
 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
-extern int vmi__split_vma(struct vma_iterator *vmi, struct mm_struct *,
-	struct vm_area_struct *, unsigned long addr, int new_below);
-extern int split_vma(struct mm_struct *, struct vm_area_struct *,
-	unsigned long addr, int new_below);
-extern int vmi_split_vma(struct vma_iterator *vmi, struct mm_struct *,
-		struct vm_area_struct *, unsigned long addr, int new_below);
+extern int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *,
+		       unsigned long addr, int new_below);
+extern int split_vma(struct vma_iterator *vmi, struct vm_area_struct *,
+			 unsigned long addr, int new_below);
 extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
 extern void unlink_file_vma(struct vm_area_struct *);
 extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
diff --git a/mm/madvise.c b/mm/madvise.c
index 2beced2d5eee..bf23d64515e1 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -153,7 +153,7 @@ static int madvise_update_vma(struct vm_area_struct *vma,
 	}
 
 	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
-	*prev = vmi_vma_merge(&vmi, mm, *prev, start, end, new_flags,
+	*prev = vma_merge(&vmi, mm, *prev, start, end, new_flags,
 			  vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
 			  vma->vm_userfaultfd_ctx, anon_name);
 	if (*prev) {
@@ -166,7 +166,7 @@ static int madvise_update_vma(struct vm_area_struct *vma,
 	if (start != vma->vm_start) {
 		if (unlikely(mm->map_count >= sysctl_max_map_count))
 			return -ENOMEM;
-		error = vmi__split_vma(&vmi, mm, vma, start, 1);
+		error = __split_vma(&vmi, vma, start, 1);
 		if (error)
 			return error;
 	}
@@ -174,7 +174,7 @@ static int madvise_update_vma(struct vm_area_struct *vma,
 	if (end != vma->vm_end) {
 		if (unlikely(mm->map_count >= sysctl_max_map_count))
 			return -ENOMEM;
-		error = vmi__split_vma(&vmi, mm, vma, end, 0);
+		error = __split_vma(&vmi, vma, end, 0);
 		if (error)
 			return error;
 	}
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 5bf4ab8eee49..ee9751323c59 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -810,7 +810,7 @@ static int mbind_range(struct mm_struct *mm, unsigned long start,
 
 		pgoff = vma->vm_pgoff +
 			((vmstart - vma->vm_start) >> PAGE_SHIFT);
-		prev = vmi_vma_merge(&vmi, mm, prev, vmstart, vmend, vma->vm_flags,
+		prev = vma_merge(&vmi, mm, prev, vmstart, vmend, vma->vm_flags,
 				 vma->anon_vma, vma->vm_file, pgoff,
 				 new_pol, vma->vm_userfaultfd_ctx,
 				 anon_vma_name(vma));
@@ -819,12 +819,12 @@ static int mbind_range(struct mm_struct *mm, unsigned long start,
 			goto replace;
 		}
 		if (vma->vm_start != vmstart) {
-			err = vmi_split_vma(&vmi, vma->vm_mm, vma, vmstart, 1);
+			err = split_vma(&vmi, vma, vmstart, 1);
 			if (err)
 				goto out;
 		}
 		if (vma->vm_end != vmend) {
-			err = vmi_split_vma(&vmi, vma->vm_mm, vma, vmend, 0);
+			err = split_vma(&vmi, vma, vmend, 0);
 			if (err)
 				goto out;
 		}
diff --git a/mm/mlock.c b/mm/mlock.c
index f06b02b631b5..393cddee2f06 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -418,7 +418,7 @@ static int mlock_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		goto out;
 
 	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
-	*prev = vmi_vma_merge(vmi, mm, *prev, start, end, newflags,
+	*prev = vma_merge(vmi, mm, *prev, start, end, newflags,
 			vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
 			vma->vm_userfaultfd_ctx, anon_vma_name(vma));
 	if (*prev) {
@@ -427,13 +427,13 @@ static int mlock_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma,
 	}
 
 	if (start != vma->vm_start) {
-		ret = vmi_split_vma(vmi, mm, vma, start, 1);
+		ret = split_vma(vmi, vma, start, 1);
 		if (ret)
 			goto out;
 	}
 
 	if (end != vma->vm_end) {
-		ret = vmi_split_vma(vmi, mm, vma, end, 0);
+		ret = split_vma(vmi, vma, end, 0);
 		if (ret)
 			goto out;
 	}
diff --git a/mm/mmap.c b/mm/mmap.c
index c22365727ab4..0c194a2a568d 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1070,7 +1070,7 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
  * parameter) may establish ptes with the wrong permissions of NNNN
  * instead of the right permissions of XXXX.
  */
-struct vm_area_struct *vma_merge(struct mm_struct *mm,
+struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
 			struct vm_area_struct *prev, unsigned long addr,
 			unsigned long end, unsigned long vm_flags,
 			struct anon_vma *anon_vma, struct file *file,
@@ -1079,7 +1079,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
 			struct anon_vma_name *anon_name)
 {
 	pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
-	struct vm_area_struct *mid, *next, *res;
+	struct vm_area_struct *mid, *next, *res = NULL;
 	int err = -1;
 	bool merge_prev = false;
 	bool merge_next = false;
@@ -1145,26 +1145,11 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
 	if (err)
 		return NULL;
 	khugepaged_enter_vma(res, vm_flags);
-	return res;
-}
 
-struct vm_area_struct *vmi_vma_merge(struct vma_iterator *vmi,
-			struct mm_struct *mm,
-			struct vm_area_struct *prev, unsigned long addr,
-			unsigned long end, unsigned long vm_flags,
-			struct anon_vma *anon_vma, struct file *file,
-			pgoff_t pgoff, struct mempolicy *policy,
-			struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
-			struct anon_vma_name *anon_name)
-{
-	struct vm_area_struct *tmp;
-
-	tmp = vma_merge(mm, prev, addr, end, vm_flags, anon_vma, file, pgoff,
-			policy, vm_userfaultfd_ctx, anon_name);
-	if (tmp)
+	if (res)
 		vma_iter_set(vmi, end);
 
-	return tmp;
+	return res;
 }
 
 /*
@@ -2287,12 +2272,14 @@ static void unmap_region(struct mm_struct *mm, struct maple_tree *mt,
  * __split_vma() bypasses sysctl_max_map_count checking.  We use this where it
  * has already been checked or doesn't make sense to fail.
  */
-int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
+int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		unsigned long addr, int new_below)
 {
 	struct vm_area_struct *new;
 	int err;
-	validate_mm_mt(mm);
+	unsigned long end = vma->vm_end;
+
+	validate_mm_mt(vma->vm_mm);
 
 	if (vma->vm_ops && vma->vm_ops->may_split) {
 		err = vma->vm_ops->may_split(vma, addr);
@@ -2332,8 +2319,10 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 		err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
 
 	/* Success. */
-	if (!err)
+	if (!err) {
+		vma_iter_set(vmi, end);
 		return 0;
+	}
 
 	/* Avoid vm accounting in close() operation */
 	new->vm_start = new->vm_end;
@@ -2348,46 +2337,21 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 	mpol_put(vma_policy(new));
  out_free_vma:
 	vm_area_free(new);
-	validate_mm_mt(mm);
+	validate_mm_mt(vma->vm_mm);
 	return err;
 }
-int vmi__split_vma(struct vma_iterator *vmi, struct mm_struct *mm,
-		   struct vm_area_struct *vma, unsigned long addr, int new_below)
-{
-	int ret;
-	unsigned long end = vma->vm_end;
-
-	ret = __split_vma(mm, vma, addr, new_below);
-	if (!ret)
-		vma_iter_set(vmi, end);
-
-	return ret;
-}
 
 /*
  * Split a vma into two pieces at address 'addr', a new vma is allocated
  * either for the first part or the tail.
  */
-int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
+int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
 	      unsigned long addr, int new_below)
 {
-	if (mm->map_count >= sysctl_max_map_count)
+	if (vma->vm_mm->map_count >= sysctl_max_map_count)
 		return -ENOMEM;
 
-	return __split_vma(mm, vma, addr, new_below);
-}
-
-int vmi_split_vma(struct vma_iterator *vmi, struct mm_struct *mm,
-		  struct vm_area_struct *vma, unsigned long addr, int new_below)
-{
-	int ret;
-	unsigned long end = vma->vm_end;
-
-	ret = split_vma(mm, vma, addr, new_below);
-	if (!ret)
-		vma_iter_set(vmi, end);
-
-	return ret;
+	return __split_vma(vmi, vma, addr, new_below);
 }
 
 static inline int munmap_sidetree(struct vm_area_struct *vma,
@@ -2447,7 +2411,7 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
 			goto map_count_exceeded;
 
-		error = vmi__split_vma(vmi, mm, vma, start, 0);
+		error = __split_vma(vmi, vma, start, 0);
 		if (error)
 			goto start_split_failed;
 
@@ -2468,7 +2432,7 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		if (next->vm_end > end) {
 			struct vm_area_struct *split;
 
-			error = vmi__split_vma(vmi, mm, next, end, 1);
+			error = __split_vma(vmi, next, end, 1);
 			if (error)
 				goto end_split_failed;
 
@@ -2749,9 +2713,10 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 		 * vma again as we may succeed this time.
 		 */
 		if (unlikely(vm_flags != vma->vm_flags && prev)) {
-			merge = vmi_vma_merge(&vmi, mm, prev, vma->vm_start,
-				vma->vm_end, vma->vm_flags, NULL, vma->vm_file,
-				vma->vm_pgoff, NULL, NULL_VM_UFFD_CTX, NULL);
+			merge = vma_merge(&vmi, mm, prev, vma->vm_start,
+				    vma->vm_end, vma->vm_flags, NULL,
+				    vma->vm_file, vma->vm_pgoff, NULL,
+				    NULL_VM_UFFD_CTX, NULL);
 			if (merge) {
 				/*
 				 * ->mmap() can change vma->vm_file and fput
@@ -3303,7 +3268,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
 	if (new_vma && new_vma->vm_start < addr + len)
 		return NULL;	/* should never get here */
 
-	new_vma = vmi_vma_merge(&vmi, mm, prev, addr, addr + len, vma->vm_flags,
+	new_vma = vma_merge(&vmi, mm, prev, addr, addr + len, vma->vm_flags,
 			    vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
 			    vma->vm_userfaultfd_ctx, anon_vma_name(vma));
 	if (new_vma) {
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 994e8d991e78..bd5c04974bbc 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -602,7 +602,7 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
 	 * First try to merge with previous and/or next vma.
 	 */
 	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
-	*pprev = vmi_vma_merge(vmi, mm, *pprev, start, end, newflags,
+	*pprev = vma_merge(vmi, mm, *pprev, start, end, newflags,
 			   vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
 			   vma->vm_userfaultfd_ctx, anon_vma_name(vma));
 	if (*pprev) {
@@ -614,13 +614,13 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
 	*pprev = vma;
 
 	if (start != vma->vm_start) {
-		error = vmi_split_vma(vmi, mm, vma, start, 1);
+		error = split_vma(vmi, vma, start, 1);
 		if (error)
 			goto fail;
 	}
 
 	if (end != vma->vm_end) {
-		error = vmi_split_vma(vmi, mm, vma, end, 0);
+		error = split_vma(vmi, vma, end, 0);
 		if (error)
 			goto fail;
 	}
diff --git a/mm/mremap.c b/mm/mremap.c
index 7302a71058ce..cbafea7fe895 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1033,7 +1033,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 			 * with the next vma if it becomes adjacent to the expanded vma and
 			 * otherwise compatible.
 			 */
-			vma = vmi_vma_merge(&vmi, mm, vma, extension_start,
+			vma = vma_merge(&vmi, mm, vma, extension_start,
 				extension_end, vma->vm_flags, vma->anon_vma,
 				vma->vm_file, extension_pgoff, vma_policy(vma),
 				vma->vm_userfaultfd_ctx, anon_vma_name(vma));
-- 
2.35.1