Unverified Commit 39f6e758 authored by Christian Brauner's avatar Christian Brauner
Browse files

userfaultfd: convert new_userfaultfd() to FD_PREPARE() 

Link: https://patch.msgid.link/20251123-work-fd-prepare-v4-16-b6efa1706cfd@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 14010faa

fs/userfaultfd.c

+10 −20
Original line number Diff line number Diff line
@@ -2111,9 +2111,7 @@ static void init_once_userfaultfd_ctx(void *mem) 


static int new_userfaultfd(int flags)

{

	struct userfaultfd_ctx *ctx;

	struct file *file;

	int fd;

	struct userfaultfd_ctx *ctx __free(kfree) = NULL;



	VM_WARN_ON_ONCE(!current->mm);
@@ -2135,26 +2133,18 @@ static int new_userfaultfd(int flags) 
	atomic_set(&ctx->mmap_changing, 0);

	ctx->mm = current->mm;



	fd = get_unused_fd_flags(flags & UFFD_SHARED_FCNTL_FLAGS);

	if (fd < 0)

		goto err_out;

	FD_PREPARE(fdf, flags & UFFD_SHARED_FCNTL_FLAGS,

		   anon_inode_create_getfile("[userfaultfd]", &userfaultfd_fops, ctx,

					     O_RDONLY | (flags & UFFD_SHARED_FCNTL_FLAGS),

					     NULL));

	if (fdf.err)

		return fdf.err;



	/* Create a new inode so that the LSM can block the creation.  */

	file = anon_inode_create_getfile("[userfaultfd]", &userfaultfd_fops, ctx,

			O_RDONLY | (flags & UFFD_SHARED_FCNTL_FLAGS), NULL);

	if (IS_ERR(file)) {

		put_unused_fd(fd);

		fd = PTR_ERR(file);

		goto err_out;

	}

	/* prevent the mm struct to be freed */

	mmgrab(ctx->mm);

	file->f_mode |= FMODE_NOWAIT;

	fd_install(fd, file);

	return fd;

err_out:

	kmem_cache_free(userfaultfd_ctx_cachep, ctx);

	return fd;

	fd_prepare_file(fdf)->f_mode |= FMODE_NOWAIT;

	retain_and_null_ptr(ctx);

	return fd_publish(fdf);

}



static inline bool userfaultfd_syscall_allowed(int flags)