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userfaultfd: shmem: use shmem_mcopy_atomic_pte for shared memory

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The shmem_mcopy_atomic_pte implements low lever part of UFFDIO_COPY
operation for shared memory VMAs.  It's based on mcopy_atomic_pte with
adjustments necessary for shared memory pages.

Link: http://lkml.kernel.org/r/20161216144821.5183-32-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 15:43:34 -08:00 committed by Linus Torvalds
parent 95cc09d66f
commit 26071cedc5
1 changed files with 21 additions and 13 deletions
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34
mm/userfaultfd.c
View file

@ -16,6 +16,7 @@
#include <linux/mmu_notifier.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/shmem_fs.h>
#include <asm/tlbflush.h>
#include "internal.h"
@ -369,7 +370,9 @@ retry:
*/
err = -EINVAL;
dst_vma = find_vma(dst_mm, dst_start);
if (!dst_vma || (dst_vma->vm_flags & VM_SHARED))
if (!dst_vma)
goto out_unlock;
if (!vma_is_shmem(dst_vma) && dst_vma->vm_flags & VM_SHARED)
goto out_unlock;
if (dst_start < dst_vma->vm_start ||
dst_start + len > dst_vma->vm_end)
@ -394,11 +397,7 @@ retry:
if (!dst_vma->vm_userfaultfd_ctx.ctx)
goto out_unlock;
/*
* FIXME: only allow copying on anonymous vmas, tmpfs should
* be added.
*/
if (!vma_is_anonymous(dst_vma))
if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma))
goto out_unlock;
/*
@ -407,7 +406,7 @@ retry:
* dst_vma.
*/
err = -ENOMEM;
if (unlikely(anon_vma_prepare(dst_vma)))
if (vma_is_anonymous(dst_vma) && unlikely(anon_vma_prepare(dst_vma)))
goto out_unlock;
while (src_addr < src_start + len) {
@ -444,12 +443,21 @@ retry:
BUG_ON(pmd_none(*dst_pmd));
BUG_ON(pmd_trans_huge(*dst_pmd));
if (!zeropage)
err = mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma,
dst_addr, src_addr, &page);
else
err = mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma,
dst_addr);
if (vma_is_anonymous(dst_vma)) {
if (!zeropage)
err = mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma,
dst_addr, src_addr,
&page);
else
err = mfill_zeropage_pte(dst_mm, dst_pmd,
dst_vma, dst_addr);
} else {
err = -EINVAL; /* if zeropage is true return -EINVAL */
if (likely(!zeropage))
err = shmem_mcopy_atomic_pte(dst_mm, dst_pmd,
dst_vma, dst_addr,
src_addr, &page);
}
cond_resched();