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Commit 26071ced authored by Mike Rapoport's avatar Mike Rapoport Committed by Linus Torvalds
Browse files

userfaultfd: shmem: use shmem_mcopy_atomic_pte for shared memory 

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: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrea 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 95cc09d6

mm/userfaultfd.c

+21 −13
Original line number Diff line number Diff line
@@ -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 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm, 
	 */

	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 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm, 
	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 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm, 
	 * 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 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm, 
		BUG_ON(pmd_none(*dst_pmd));

		BUG_ON(pmd_trans_huge(*dst_pmd));



		if (vma_is_anonymous(dst_vma)) {

			if (!zeropage)

				err = mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma,

					       dst_addr, src_addr, &page);

						       dst_addr, src_addr,

						       &page);

			else

			err = mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma,

						 dst_addr);

				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();