| Message ID | 20171229212403.22800-1-ebiggers3@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Dec 29, 2017 at 03:24:03PM -0600, Eric Biggers wrote: > From: Eric Biggers <ebiggers@google.com> > > 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. > > Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com> > --- > fs/userfaultfd.c | 70 ++++++++------------------------------------------------ > 1 file changed, 9 insertions(+), 61 deletions(-) > > diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c > index 41a75f9f23fd..b87cc2c5cfb1 100644 > --- a/fs/userfaultfd.c > +++ b/fs/userfaultfd.c > @@ -985,24 +985,14 @@ 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; > } > > @@ -1884,24 +1874,10 @@ 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); > > @@ -1909,14 +1885,12 @@ 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; > @@ -1927,39 +1901,13 @@ 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) > -- > 2.15.1 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> >
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 41a75f9f23fd..b87cc2c5cfb1 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -985,24 +985,14 @@ 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; } @@ -1884,24 +1874,10 @@ 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); @@ -1909,14 +1885,12 @@ 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; @@ -1927,39 +1901,13 @@ 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)