mm/userfaultfd: Create uffd_writeprotect() to do write protect of each vma

writeprotect checks the memory types, so extract the contents that does
the work to its own function for later modularization.

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 7fd74ae2b809b38a43c6cd974235e109d5313b41..1bdccadcaeb3545f16a1cf4677d8a5ac5c1d6ce8 100644 (file)
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -784,16 +784,41 @@ long uffd_wp_range(struct vm_area_struct *dst_vma,
        return ret;
 }
 
+static int uffd_writeprotect(struct uffd_info *info)
+{
+       long err;
+       struct vm_area_struct *dst_vma;
+       unsigned long end = info->src_addr + info->len;
+       unsigned long _start, _end;
+
+       dst_vma = info->dst_vma;
+       if (!userfaultfd_wp(dst_vma))
+               return -ENOENT;
+
+       if (is_vm_hugetlb_page(dst_vma)) {
+               unsigned long page_mask;
+               page_mask = vma_kernel_pagesize(dst_vma) - 1;
+               if ((info->src_addr & page_mask) || (info->len & page_mask))
+                       return -EINVAL;
+       }
+
+       _start = max(dst_vma->vm_start, info->src_addr);
+       _end = min(dst_vma->vm_end, end);
+
+       err = uffd_wp_range(dst_vma, _start, _end - _start, info->wp);
+       if (err < 0)
+               return err;
+
+       return 0;
+}
+
 int mwriteprotect_range(struct userfaultfd_ctx *ctx, unsigned long start,
                        unsigned long len, bool enable_wp)
 {
        struct mm_struct *dst_mm = ctx->mm;
-       unsigned long end = start + len;
-       unsigned long _start, _end;
-       struct vm_area_struct *dst_vma;
-       unsigned long page_mask;
        long err;
        VMA_ITERATOR(vmi, dst_mm, start);
+       struct uffd_info info = UFFD_STRUCT_INIT(0, start, len, ctx, enable_wp);
 
        /*
         * Sanitize the command parameters:
@@ -817,30 +842,12 @@ int mwriteprotect_range(struct userfaultfd_ctx *ctx, unsigned long start,
                goto out_unlock;
 
        err = -ENOENT;
-       for_each_vma_range(vmi, dst_vma, end) {
-
-               if (!userfaultfd_wp(dst_vma)) {
-                       err = -ENOENT;
-                       break;
-               }
-
-               if (is_vm_hugetlb_page(dst_vma)) {
-                       err = -EINVAL;
-                       page_mask = vma_kernel_pagesize(dst_vma) - 1;
-                       if ((start & page_mask) || (len & page_mask))
-                               break;
-               }
-
-               _start = max(dst_vma->vm_start, start);
-               _end = min(dst_vma->vm_end, end);
-
-               err = uffd_wp_range(dst_vma, _start, _end - _start, enable_wp);
-
-               /* Return 0 on success, <0 on failures */
-               if (err < 0)
+       for_each_vma_range(vmi, info.dst_vma, start + len) {
+               err = uffd_writeprotect(&info);
+               if (err)
                        break;
-               err = 0;
        }
+
 out_unlock:
        up_read(&ctx->map_changing_lock);
        mmap_read_unlock(dst_mm);