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Diffstat (limited to 'mm')
-rw-r--r--mm/userfaultfd.c56
1 files changed, 32 insertions, 24 deletions
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 07f44555fd03..a10aa8563e41 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -18,6 +18,36 @@
#include <asm/tlbflush.h>
#include "internal.h"
+static __always_inline
+struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm,
+ unsigned long dst_start,
+ unsigned long len)
+{
+ /*
+ * Make sure that the dst range is both valid and fully within a
+ * single existing vma.
+ */
+ struct vm_area_struct *dst_vma;
+
+ dst_vma = find_vma(dst_mm, dst_start);
+ if (!dst_vma)
+ return NULL;
+
+ if (dst_start < dst_vma->vm_start ||
+ dst_start + len > dst_vma->vm_end)
+ return NULL;
+
+ /*
+ * Check the vma is registered in uffd, this is required to
+ * enforce the VM_MAYWRITE check done at uffd registration
+ * time.
+ */
+ if (!dst_vma->vm_userfaultfd_ctx.ctx)
+ return NULL;
+
+ return dst_vma;
+}
+
static int mcopy_atomic_pte(struct mm_struct *dst_mm,
pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
@@ -220,20 +250,9 @@ retry:
*/
if (!dst_vma) {
err = -ENOENT;
- dst_vma = find_vma(dst_mm, dst_start);
+ dst_vma = find_dst_vma(dst_mm, dst_start, len);
if (!dst_vma || !is_vm_hugetlb_page(dst_vma))
goto out_unlock;
- /*
- * Check the vma is registered in uffd, this is
- * required to enforce the VM_MAYWRITE check done at
- * uffd registration time.
- */
- if (!dst_vma->vm_userfaultfd_ctx.ctx)
- goto out_unlock;
-
- if (dst_start < dst_vma->vm_start ||
- dst_start + len > dst_vma->vm_end)
- goto out_unlock;
err = -EINVAL;
if (vma_hpagesize != vma_kernel_pagesize(dst_vma))
@@ -468,20 +487,9 @@ retry:
* both valid and fully within a single existing vma.
*/
err = -ENOENT;
- dst_vma = find_vma(dst_mm, dst_start);
+ dst_vma = find_dst_vma(dst_mm, dst_start, len);
if (!dst_vma)
goto out_unlock;
- /*
- * Check the vma is registered in uffd, this is required to
- * enforce the VM_MAYWRITE check done at uffd registration
- * time.
- */
- if (!dst_vma->vm_userfaultfd_ctx.ctx)
- goto out_unlock;
-
- if (dst_start < dst_vma->vm_start ||
- dst_start + len > dst_vma->vm_end)
- goto out_unlock;
err = -EINVAL;
/*