btrfs: remove duplicated include in block-group.c

[linux-2.6-microblaze.git] / mm / userfaultfd.c

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 7d6ab05..512576e 100644 (file)
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -638,3 +638,57 @@ ssize_t mfill_zeropage(struct mm_struct *dst_mm, unsigned long start,
 {
        return __mcopy_atomic(dst_mm, start, 0, len, true, mmap_changing, 0);
 }
+
+int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
+                       unsigned long len, bool enable_wp, bool *mmap_changing)
+{
+       struct vm_area_struct *dst_vma;
+       pgprot_t newprot;
+       int err;
+
+       /*
+        * Sanitize the command parameters:
+        */
+       BUG_ON(start & ~PAGE_MASK);
+       BUG_ON(len & ~PAGE_MASK);
+
+       /* Does the address range wrap, or is the span zero-sized? */
+       BUG_ON(start + len <= start);
+
+       down_read(&dst_mm->mmap_sem);
+
+       /*
+        * If memory mappings are changing because of non-cooperative
+        * operation (e.g. mremap) running in parallel, bail out and
+        * request the user to retry later
+        */
+       err = -EAGAIN;
+       if (mmap_changing && READ_ONCE(*mmap_changing))
+               goto out_unlock;
+
+       err = -ENOENT;
+       dst_vma = find_dst_vma(dst_mm, start, len);
+       /*
+        * Make sure the vma is not shared, that the dst range is
+        * both valid and fully within a single existing vma.
+        */
+       if (!dst_vma || (dst_vma->vm_flags & VM_SHARED))
+               goto out_unlock;
+       if (!userfaultfd_wp(dst_vma))
+               goto out_unlock;
+       if (!vma_is_anonymous(dst_vma))
+               goto out_unlock;
+
+       if (enable_wp)
+               newprot = vm_get_page_prot(dst_vma->vm_flags & ~(VM_WRITE));
+       else
+               newprot = vm_get_page_prot(dst_vma->vm_flags);
+
+       change_protection(dst_vma, start, start + len, newprot,
+                         enable_wp ? MM_CP_UFFD_WP : MM_CP_UFFD_WP_RESOLVE);
+
+       err = 0;
+out_unlock:
+       up_read(&dst_mm->mmap_sem);
+       return err;
+}