diff options
author | Eric Biggers <ebiggers@google.com> | 2018-01-31 16:19:48 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-01-31 17:18:39 -0800 |
commit | 284cd241a18ee6d999296f8ff3104eb6d2fc898f (patch) | |
tree | 001b843c3d63357e0a6a7dbb95192bd5feba116d | |
parent | c5c63835e5713b09fc974241db47956362a63efa (diff) |
userfaultfd: convert to use anon_inode_getfd()
Nothing actually calls userfaultfd_file_create() besides the
userfaultfd() system call itself. So simplify things by folding it into
the system call and using anon_inode_getfd() instead of
anon_inode_getfile(). Do the same in resolve_userfault_fork() as well.
This removes over 50 lines with no change in functionality.
Link: http://lkml.kernel.org/r/20171229212403.22800-1-ebiggers3@gmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | fs/userfaultfd.c | 70 |
1 files changed, 9 insertions, 61 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index a9d0ddc12ace..87a13a7c8270 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -988,24 +988,14 @@ static int resolve_userfault_fork(struct userfaultfd_ctx *ctx, struct uffd_msg *msg) { int fd; - struct file *file; - unsigned int flags = new->flags & UFFD_SHARED_FCNTL_FLAGS; - fd = get_unused_fd_flags(flags); + fd = anon_inode_getfd("[userfaultfd]", &userfaultfd_fops, new, + O_RDWR | (new->flags & UFFD_SHARED_FCNTL_FLAGS)); if (fd < 0) return fd; - file = anon_inode_getfile("[userfaultfd]", &userfaultfd_fops, new, - O_RDWR | flags); - if (IS_ERR(file)) { - put_unused_fd(fd); - return PTR_ERR(file); - } - - fd_install(fd, file); msg->arg.reserved.reserved1 = 0; msg->arg.fork.ufd = fd; - return 0; } @@ -1887,24 +1877,10 @@ static void init_once_userfaultfd_ctx(void *mem) seqcount_init(&ctx->refile_seq); } -/** - * userfaultfd_file_create - Creates a userfaultfd file pointer. - * @flags: Flags for the userfaultfd file. - * - * This function creates a userfaultfd file pointer, w/out installing - * it into the fd table. This is useful when the userfaultfd file is - * used during the initialization of data structures that require - * extra setup after the userfaultfd creation. So the userfaultfd - * creation is split into the file pointer creation phase, and the - * file descriptor installation phase. In this way races with - * userspace closing the newly installed file descriptor can be - * avoided. Returns a userfaultfd file pointer, or a proper error - * pointer. - */ -static struct file *userfaultfd_file_create(int flags) +SYSCALL_DEFINE1(userfaultfd, int, flags) { - struct file *file; struct userfaultfd_ctx *ctx; + int fd; BUG_ON(!current->mm); @@ -1912,14 +1888,12 @@ static struct file *userfaultfd_file_create(int flags) BUILD_BUG_ON(UFFD_CLOEXEC != O_CLOEXEC); BUILD_BUG_ON(UFFD_NONBLOCK != O_NONBLOCK); - file = ERR_PTR(-EINVAL); if (flags & ~UFFD_SHARED_FCNTL_FLAGS) - goto out; + return -EINVAL; - file = ERR_PTR(-ENOMEM); ctx = kmem_cache_alloc(userfaultfd_ctx_cachep, GFP_KERNEL); if (!ctx) - goto out; + return -ENOMEM; atomic_set(&ctx->refcount, 1); ctx->flags = flags; @@ -1930,39 +1904,13 @@ static struct file *userfaultfd_file_create(int flags) /* prevent the mm struct to be freed */ mmgrab(ctx->mm); - file = anon_inode_getfile("[userfaultfd]", &userfaultfd_fops, ctx, - O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS)); - if (IS_ERR(file)) { + fd = anon_inode_getfd("[userfaultfd]", &userfaultfd_fops, ctx, + O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS)); + if (fd < 0) { mmdrop(ctx->mm); kmem_cache_free(userfaultfd_ctx_cachep, ctx); } -out: - return file; -} - -SYSCALL_DEFINE1(userfaultfd, int, flags) -{ - int fd, error; - struct file *file; - - error = get_unused_fd_flags(flags & UFFD_SHARED_FCNTL_FLAGS); - if (error < 0) - return error; - fd = error; - - file = userfaultfd_file_create(flags); - if (IS_ERR(file)) { - error = PTR_ERR(file); - goto err_put_unused_fd; - } - fd_install(fd, file); - return fd; - -err_put_unused_fd: - put_unused_fd(fd); - - return error; } static int __init userfaultfd_init(void) |