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.
Signed-off-by: Mike Rapoport <[email protected]> --- 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 --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 2aab2e1..2f9c87e 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1068,7 +1068,8 @@ 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, @@ -1081,7 +1082,7 @@ 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; @@ -1138,13 +1139,9 @@ 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(); @@ -1188,8 +1185,8 @@ 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; } @@ -1260,7 +1257,7 @@ 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; @@ -1320,10 +1317,6 @@ 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 7a386c5..a9c3389 100644 --- a/include/uapi/linux/userfaultfd.h +++ b/include/uapi/linux/userfaultfd.h @@ -31,7 +31,7 @@ (__u64)1 << _UFFDIO_COPY | \ (__u64)1 << _UFFDIO_ZEROPAGE | \ (__u64)1 << _UFFDIO_WRITEPROTECT) -#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 3011711..d753a91 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) { -- 1.9.1
