From: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Subject: 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@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> --- fs/userfaultfd.c | 21 +++++++-------------- include/uapi/linux/userfaultfd.h | 2 +- tools/testing/selftests/vm/userfaultfd.c | 2 +- 3 files changed, 9 insertions(+), 16 deletions(-) diff -puN fs/userfaultfd.c~userfaultfd-shmem-allow-registration-of-shared-memory-ranges fs/userfaultfd.c --- a/fs/userfaultfd.c~userfaultfd-shmem-allow-registration-of-shared-memory-ranges +++ a/fs/userfaultfd.c @@ -1098,7 +1098,8 @@ static __always_inline int validate_rang 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 u 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 u /* * 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 u /* * 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 /* * 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 -puN include/uapi/linux/userfaultfd.h~userfaultfd-shmem-allow-registration-of-shared-memory-ranges include/uapi/linux/userfaultfd.h --- a/include/uapi/linux/userfaultfd.h~userfaultfd-shmem-allow-registration-of-shared-memory-ranges +++ a/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 -puN tools/testing/selftests/vm/userfaultfd.c~userfaultfd-shmem-allow-registration-of-shared-memory-ranges tools/testing/selftests/vm/userfaultfd.c --- a/tools/testing/selftests/vm/userfaultfd.c~userfaultfd-shmem-allow-registration-of-shared-memory-ranges +++ a/tools/testing/selftests/vm/userfaultfd.c @@ -129,7 +129,7 @@ static void allocate_area(void **alloc_a #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) { _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
