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authorMike Rapoport <rppt@linux.vnet.ibm.com>2017-02-23 02:43:40 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-23 03:41:28 +0300
commitcac673292b9b39493bb0ff526b96c83ace6fdcd0 (patch)
tree7d8dbcd6cabcdf35cc2866b672c65be98cc1e5be
parentcfda05267f7bd02b5ae5ac6a37fbbdf3b9c41b57 (diff)
downloadlinux-cac673292b9b39493bb0ff526b96c83ace6fdcd0.tar.xz
userfaultfd: shmem: allow registration of shared memory ranges
Expand the userfaultfd_register/unregister routines to allow shared memory VMAs. Currently, there is no UFFDIO_ZEROPAGE and write-protection support for shared memory VMAs, which is reflected in ioctl methods supported by uffdio_register. Link: http://lkml.kernel.org/r/20161216144821.5183-34-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>
-rw-r--r--fs/userfaultfd.c21
-rw-r--r--include/uapi/linux/userfaultfd.h2
-rw-r--r--tools/testing/selftests/vm/userfaultfd.c2
3 files changed, 9 insertions, 16 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 593135c296bc..18406158e13f 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1098,7 +1098,8 @@ static __always_inline int validate_range(struct mm_struct *mm,
static inline bool vma_can_userfault(struct vm_area_struct *vma)
{
- return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma);
+ return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
+ vma_is_shmem(vma);
}
static int userfaultfd_register(struct userfaultfd_ctx *ctx,
@@ -1111,7 +1112,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
struct uffdio_register __user *user_uffdio_register;
unsigned long vm_flags, new_flags;
bool found;
- bool huge_pages;
+ bool non_anon_pages;
unsigned long start, end, vma_end;
user_uffdio_register = (struct uffdio_register __user *) arg;
@@ -1175,13 +1176,9 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
/*
* Search for not compatible vmas.
- *
- * FIXME: this shall be relaxed later so that it doesn't fail
- * on tmpfs backed vmas (in addition to the current allowance
- * on anonymous vmas).
*/
found = false;
- huge_pages = false;
+ non_anon_pages = false;
for (cur = vma; cur && cur->vm_start < end; cur = cur->vm_next) {
cond_resched();
@@ -1220,8 +1217,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
/*
* Note vmas containing huge pages
*/
- if (is_vm_hugetlb_page(cur))
- huge_pages = true;
+ if (is_vm_hugetlb_page(cur) || vma_is_shmem(cur))
+ non_anon_pages = true;
found = true;
}
@@ -1292,7 +1289,7 @@ out_unlock:
* userland which ioctls methods are guaranteed to
* succeed on this range.
*/
- if (put_user(huge_pages ? UFFD_API_RANGE_IOCTLS_HPAGE :
+ if (put_user(non_anon_pages ? UFFD_API_RANGE_IOCTLS_BASIC :
UFFD_API_RANGE_IOCTLS,
&user_uffdio_register->ioctls))
ret = -EFAULT;
@@ -1352,10 +1349,6 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
/*
* Search for not compatible vmas.
- *
- * FIXME: this shall be relaxed later so that it doesn't fail
- * on tmpfs backed vmas (in addition to the current allowance
- * on anonymous vmas).
*/
found = false;
ret = -EINVAL;
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index 7293321abdfb..10631a4cdb24 100644
--- a/include/uapi/linux/userfaultfd.h
+++ b/include/uapi/linux/userfaultfd.h
@@ -30,7 +30,7 @@
((__u64)1 << _UFFDIO_WAKE | \
(__u64)1 << _UFFDIO_COPY | \
(__u64)1 << _UFFDIO_ZEROPAGE)
-#define UFFD_API_RANGE_IOCTLS_HPAGE \
+#define UFFD_API_RANGE_IOCTLS_BASIC \
((__u64)1 << _UFFDIO_WAKE | \
(__u64)1 << _UFFDIO_COPY)
diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 3011711212ca..d753a9161411 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -129,7 +129,7 @@ static void allocate_area(void **alloc_area)
#else /* HUGETLB_TEST */
-#define EXPECTED_IOCTLS UFFD_API_RANGE_IOCTLS_HPAGE
+#define EXPECTED_IOCTLS UFFD_API_RANGE_IOCTLS_BASIC
static int release_pages(char *rel_area)
{