mm: switch vma_merge(), split_vma(), and __split_vma to vma iterator

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

Link: https://lkml.kernel.org/r/20230120162650.984577-30-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/userfaultfd.c

@@ -909,7 +909,7 @@ 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),
@@ -1452,7 +1452,7 @@ 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 }),
@@ -1463,12 +1463,12 @@ 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;
 		}
@@ -1632,7 +1632,7 @@ 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));
@@ -1641,12 +1641,12 @@ 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) {
-			ret = vmi_split_vma(&vmi, mm, vma, end, 0);
+			ret = split_vma(&vmi, vma, end, 0);
 			if (ret)
 				break;
 		}

include/linux/mm.h

@@ -2839,24 +2839,16 @@ 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 __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 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 **,

mm/madvise.c

@@ -150,7 +150,7 @@ 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) {
@@ -163,7 +163,7 @@ 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;
 	}
@@ -171,7 +171,7 @@ 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;
 	}

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;
 		}

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;
 	}

mm/mmap.c

@@ -1010,7 +1010,7 @@ 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,
@@ -1019,7 +1019,7 @@ 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;
@@ -1085,26 +1085,11 @@ 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;
 }
 
 /*
@@ -2228,12 +2213,14 @@ 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);
@@ -2273,8 +2260,10 @@ 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;
@@ -2289,46 +2278,21 @@ 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,
@@ -2388,7 +2352,7 @@ 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;
 
@@ -2409,7 +2373,7 @@ 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;
 
@@ -2690,9 +2654,10 @@ 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
@@ -3249,7 +3214,7 @@ 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) {

mm/mprotect.c

@@ -642,7 +642,7 @@ 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) {
@@ -654,13 +654,13 @@ 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;
 	}

mm/mremap.c

@@ -1043,12 +1043,10 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 			 * when a vma would be actually removed due to a merge.
 			 */
 			if (!vma->vm_ops || !vma->vm_ops->close) {
-				vma = vmi_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));
+				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));
 			} else if (vma_adjust(vma, vma->vm_start, addr + new_len,
 				   vma->vm_pgoff, NULL)) {
 				vma = NULL;

mm/nommu.c

@@ -1297,18 +1297,20 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
  * split a vma into two pieces at address 'addr', a new vma is allocated either
  * for the first part or the tail.
  */
-int vmi_split_vma(struct vma_iterator *vmi, struct mm_struct *mm,
-		  struct vm_area_struct *vma, unsigned long addr, int new_below)
+int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
+	      unsigned long addr, int new_below)
 {
 	struct vm_area_struct *new;
 	struct vm_region *region;
 	unsigned long npages;
+	struct mm_struct *mm;
 
 	/* we're only permitted to split anonymous regions (these should have
 	 * only a single usage on the region) */
 	if (vma->vm_file)
 		return -ENOMEM;
 
+	mm = vma->vm_mm;
 	if (mm->map_count >= sysctl_max_map_count)
 		return -ENOMEM;
 
@@ -1465,7 +1467,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list
 		if (end != vma->vm_end && offset_in_page(end))
 			return -EINVAL;
 		if (start != vma->vm_start && end != vma->vm_end) {
-			ret = vmi_split_vma(&vmi, mm, vma, start, 1);
+			ret = split_vma(&vmi, vma, start, 1);
 			if (ret < 0)
 				return ret;
 		}