userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support

shmem_mcopy_atomic_pte is the low level routine that implements the
userfaultfd UFFDIO_COPY command.  It is based on the existing
mcopy_atomic_pte routine with modifications for shared memory pages.

Link: http://lkml.kernel.org/r/20161216144821.5183-29-aarcange@redhat.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michael Rapoport <RAPOPORT@il.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Rapoport
2017-02-22 15:43:25 -08:00
committed by Linus Torvalds
parent ba6907db6d
commit 4c27fe4c4c
2 changed files with 121 additions and 0 deletions

View File

@@ -124,4 +124,15 @@ static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
}
#endif
#ifdef CONFIG_SHMEM
extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
struct page **pagep);
#else
#define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
src_addr, pagep) ({ BUG(); 0; })
#endif
#endif