The patch titled
Subject: userfaultfd: shmem: use shmem_mcopy_atomic_pte for shared memory
has been added to the -mm tree. Its filename is
userfaultfd-shmem-use-shmem_mcopy_atomic_pte-for-shared-memory.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-shmem-use-shmem_mcopy_atomic_pte-for-shared-memory.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-shmem-use-shmem_mcopy_atomic_pte-for-shared-memory.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxx
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Michael Rapoport <RAPOPORT@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/userfaultfd.c | 34 +++++++++++++++++++++-------------
1 file changed, 21 insertions(+), 13 deletions(-)
diff -puN mm/userfaultfd.c~userfaultfd-shmem-use-shmem_mcopy_atomic_pte-for-shared-memory mm/userfaultfd.c
--- a/mm/userfaultfd.c~userfaultfd-shmem-use-shmem_mcopy_atomic_pte-for-shared-memory
+++ a/mm/userfaultfd.c
@@ -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();
_
Patches currently in -mm which might be from rppt@xxxxxxxxxxxxxxxxxx are
userfaultfd-non-cooperative-dup_userfaultfd-use-mm_count-instead-of-mm_users.patch
userfaultfd-introduce-vma_can_userfault.patch
userfaultfd-shmem-add-shmem_mcopy_atomic_pte-for-userfaultfd-support.patch
userfaultfd-shmem-introduce-vma_is_shmem.patch
userfaultfd-shmem-use-shmem_mcopy_atomic_pte-for-shared-memory.patch
userfaultfd-shmem-add-userfaultfd-hook-for-shared-memory-faults.patch
userfaultfd-shmem-allow-registration-of-shared-memory-ranges.patch
userfaultfd-shmem-add-userfaultfd_shmem-test.patch
userfaultfd-non-cooperative-selftest-introduce-userfaultfd_open.patch
userfaultfd-non-cooperative-selftest-add-ufd-parameter-to-copy_page.patch
userfaultfd-non-cooperative-selftest-add-test-for-fork-madvdontneed-and-remap-events.patch
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