mm/uffd: enable write protection for shmem & hugetlbfs
We've had all the necessary changes ready for both shmem and hugetlbfs. Turn on all the shmem/hugetlbfs switches for userfaultfd-wp. We can expand UFFD_API_RANGE_IOCTLS_BASIC with _UFFDIO_WRITEPROTECT too because all existing types now support write protection mode. Since vma_can_userfault() will be used elsewhere, move into userfaultfd_k.h. Link: https://lkml.kernel.org/r/20220405014926.15101-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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8e165e733b
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4 changed files with 34 additions and 26 deletions
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@ -1258,24 +1258,6 @@ static __always_inline int validate_range(struct mm_struct *mm,
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return 0;
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return 0;
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}
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}
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static inline bool vma_can_userfault(struct vm_area_struct *vma,
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unsigned long vm_flags)
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{
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/* FIXME: add WP support to hugetlbfs and shmem */
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if (vm_flags & VM_UFFD_WP) {
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if (is_vm_hugetlb_page(vma) || vma_is_shmem(vma))
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return false;
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}
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if (vm_flags & VM_UFFD_MINOR) {
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if (!(is_vm_hugetlb_page(vma) || vma_is_shmem(vma)))
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return false;
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}
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return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
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vma_is_shmem(vma);
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}
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static int userfaultfd_register(struct userfaultfd_ctx *ctx,
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static int userfaultfd_register(struct userfaultfd_ctx *ctx,
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unsigned long arg)
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unsigned long arg)
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{
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{
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@ -1956,6 +1938,9 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
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#endif
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#endif
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#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP
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#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP
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uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP;
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uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP;
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#endif
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#ifndef CONFIG_PTE_MARKER_UFFD_WP
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uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM;
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#endif
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#endif
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uffdio_api.ioctls = UFFD_API_IOCTLS;
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uffdio_api.ioctls = UFFD_API_IOCTLS;
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ret = -EFAULT;
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ret = -EFAULT;
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@ -18,6 +18,7 @@
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#include <linux/swap.h>
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#include <linux/swap.h>
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#include <linux/swapops.h>
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#include <linux/swapops.h>
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#include <asm-generic/pgtable_uffd.h>
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#include <asm-generic/pgtable_uffd.h>
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#include <linux/hugetlb_inline.h>
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/* The set of all possible UFFD-related VM flags. */
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/* The set of all possible UFFD-related VM flags. */
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#define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR)
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#define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR)
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@ -140,6 +141,25 @@ static inline bool userfaultfd_armed(struct vm_area_struct *vma)
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return vma->vm_flags & __VM_UFFD_FLAGS;
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return vma->vm_flags & __VM_UFFD_FLAGS;
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}
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}
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static inline bool vma_can_userfault(struct vm_area_struct *vma,
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unsigned long vm_flags)
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{
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if (vm_flags & VM_UFFD_MINOR)
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return is_vm_hugetlb_page(vma) || vma_is_shmem(vma);
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#ifndef CONFIG_PTE_MARKER_UFFD_WP
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/*
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* If user requested uffd-wp but not enabled pte markers for
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* uffd-wp, then shmem & hugetlbfs are not supported but only
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* anonymous.
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*/
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if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma))
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return false;
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#endif
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return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
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vma_is_shmem(vma);
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}
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extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
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extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
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extern void dup_userfaultfd_complete(struct list_head *);
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extern void dup_userfaultfd_complete(struct list_head *);
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@ -33,7 +33,8 @@
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UFFD_FEATURE_THREAD_ID | \
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UFFD_FEATURE_THREAD_ID | \
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UFFD_FEATURE_MINOR_HUGETLBFS | \
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UFFD_FEATURE_MINOR_HUGETLBFS | \
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UFFD_FEATURE_MINOR_SHMEM | \
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UFFD_FEATURE_MINOR_SHMEM | \
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UFFD_FEATURE_EXACT_ADDRESS)
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UFFD_FEATURE_EXACT_ADDRESS | \
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UFFD_FEATURE_WP_HUGETLBFS_SHMEM)
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#define UFFD_API_IOCTLS \
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#define UFFD_API_IOCTLS \
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((__u64)1 << _UFFDIO_REGISTER | \
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((__u64)1 << _UFFDIO_REGISTER | \
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(__u64)1 << _UFFDIO_UNREGISTER | \
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(__u64)1 << _UFFDIO_UNREGISTER | \
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@ -47,7 +48,8 @@
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#define UFFD_API_RANGE_IOCTLS_BASIC \
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#define UFFD_API_RANGE_IOCTLS_BASIC \
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((__u64)1 << _UFFDIO_WAKE | \
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((__u64)1 << _UFFDIO_WAKE | \
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(__u64)1 << _UFFDIO_COPY | \
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(__u64)1 << _UFFDIO_COPY | \
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(__u64)1 << _UFFDIO_CONTINUE)
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(__u64)1 << _UFFDIO_CONTINUE | \
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(__u64)1 << _UFFDIO_WRITEPROTECT)
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/*
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/*
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* Valid ioctl command number range with this API is from 0x00 to
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* Valid ioctl command number range with this API is from 0x00 to
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@ -194,6 +196,9 @@ struct uffdio_api {
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* UFFD_FEATURE_EXACT_ADDRESS indicates that the exact address of page
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* UFFD_FEATURE_EXACT_ADDRESS indicates that the exact address of page
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* faults would be provided and the offset within the page would not be
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* faults would be provided and the offset within the page would not be
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* masked.
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* masked.
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*
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* UFFD_FEATURE_WP_HUGETLBFS_SHMEM indicates that userfaultfd
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* write-protection mode is supported on both shmem and hugetlbfs.
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*/
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*/
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#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0)
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#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0)
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#define UFFD_FEATURE_EVENT_FORK (1<<1)
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#define UFFD_FEATURE_EVENT_FORK (1<<1)
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@ -207,6 +212,7 @@ struct uffdio_api {
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#define UFFD_FEATURE_MINOR_HUGETLBFS (1<<9)
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#define UFFD_FEATURE_MINOR_HUGETLBFS (1<<9)
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#define UFFD_FEATURE_MINOR_SHMEM (1<<10)
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#define UFFD_FEATURE_MINOR_SHMEM (1<<10)
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#define UFFD_FEATURE_EXACT_ADDRESS (1<<11)
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#define UFFD_FEATURE_EXACT_ADDRESS (1<<11)
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#define UFFD_FEATURE_WP_HUGETLBFS_SHMEM (1<<12)
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__u64 features;
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__u64 features;
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__u64 ioctls;
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__u64 ioctls;
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@ -732,15 +732,12 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
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err = -ENOENT;
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err = -ENOENT;
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dst_vma = find_dst_vma(dst_mm, start, len);
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dst_vma = find_dst_vma(dst_mm, start, len);
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/*
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* Make sure the vma is not shared, that the dst range is
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if (!dst_vma)
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* both valid and fully within a single existing vma.
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*/
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if (!dst_vma || (dst_vma->vm_flags & VM_SHARED))
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goto out_unlock;
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goto out_unlock;
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if (!userfaultfd_wp(dst_vma))
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if (!userfaultfd_wp(dst_vma))
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goto out_unlock;
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goto out_unlock;
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if (!vma_is_anonymous(dst_vma))
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if (!vma_can_userfault(dst_vma, dst_vma->vm_flags))
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goto out_unlock;
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goto out_unlock;
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if (is_vm_hugetlb_page(dst_vma)) {
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if (is_vm_hugetlb_page(dst_vma)) {
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