vfs-6.19-rc1.fd_prepare.fs

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Merge tag 'vfs-6.19-rc1.fd_prepare.fs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull fd prepare updates from Christian Brauner:
 "This adds the FD_ADD() and FD_PREPARE() primitive. They simplify the
  common pattern of get_unused_fd_flags() + create file + fd_install()
  that is used extensively throughout the kernel and currently requires
  cumbersome cleanup paths.

  FD_ADD() - For simple cases where a file is installed immediately:

      fd = FD_ADD(O_CLOEXEC, vfio_device_open_file(device));
      if (fd < 0)
          vfio_device_put_registration(device);
      return fd;

  FD_PREPARE() - For cases requiring access to the fd or file, or
  additional work before publishing:

      FD_PREPARE(fdf, O_CLOEXEC, sync_file->file);
      if (fdf.err) {
          fput(sync_file->file);
          return fdf.err;
      }

      data.fence = fd_prepare_fd(fdf);
      if (copy_to_user((void __user *)arg, &data, sizeof(data)))
          return -EFAULT;

      return fd_publish(fdf);

  The primitives are centered around struct fd_prepare. FD_PREPARE()
  encapsulates all allocation and cleanup logic and must be followed by
  a call to fd_publish() which associates the fd with the file and
  installs it into the caller's fdtable. If fd_publish() isn't called,
  both are deallocated automatically. FD_ADD() is a shorthand that does
  fd_publish() immediately and never exposes the struct to the caller.

  I've implemented this in a way that it's compatible with the cleanup
  infrastructure while also being usable separately. IOW, it's centered
  around struct fd_prepare which is aliased to class_fd_prepare_t and so
  we can make use of all the basica guard infrastructure"

* tag 'vfs-6.19-rc1.fd_prepare.fs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (42 commits)
  io_uring: convert io_create_mock_file() to FD_PREPARE()
  file: convert replace_fd() to FD_PREPARE()
  vfio: convert vfio_group_ioctl_get_device_fd() to FD_ADD()
  tty: convert ptm_open_peer() to FD_ADD()
  ntsync: convert ntsync_obj_get_fd() to FD_PREPARE()
  media: convert media_request_alloc() to FD_PREPARE()
  hv: convert mshv_ioctl_create_partition() to FD_ADD()
  gpio: convert linehandle_create() to FD_PREPARE()
  pseries: port papr_rtas_setup_file_interface() to FD_ADD()
  pseries: convert papr_platform_dump_create_handle() to FD_ADD()
  spufs: convert spufs_gang_open() to FD_PREPARE()
  papr-hvpipe: convert papr_hvpipe_dev_create_handle() to FD_PREPARE()
  spufs: convert spufs_context_open() to FD_PREPARE()
  net/socket: convert __sys_accept4_file() to FD_ADD()
  net/socket: convert sock_map_fd() to FD_ADD()
  net/kcm: convert kcm_ioctl() to FD_PREPARE()
  net/handshake: convert handshake_nl_accept_doit() to FD_PREPARE()
  secretmem: convert memfd_secret() to FD_ADD()
  memfd: convert memfd_create() to FD_ADD()
  bpf: convert bpf_token_create() to FD_PREPARE()
  ...

arch/powerpc/platforms/cell/spufs/inode.c

@@ -267,22 +267,11 @@ spufs_mkdir(struct inode *dir, struct dentry *dentry, unsigned int flags,
 
 static int spufs_context_open(const struct path *path)
 {
-	int ret;
+	FD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred()));
-	struct file *filp;
+	if (fdf.err)
-
+		return fdf.err;
-	ret = get_unused_fd_flags(0);
+	fd_prepare_file(fdf)->f_op = &spufs_context_fops;
-	if (ret < 0)
+	return fd_publish(fdf);
-		return ret;
-
-	filp = dentry_open(path, O_RDONLY, current_cred());
-	if (IS_ERR(filp)) {
-		put_unused_fd(ret);
-		return PTR_ERR(filp);
-	}
-
-	filp->f_op = &spufs_context_fops;
-	fd_install(ret, filp);
-	return ret;
 }
 
 static struct spu_context *
@@ -508,26 +497,15 @@ static const struct file_operations spufs_gang_fops = {
 
 static int spufs_gang_open(const struct path *path)
 {
-	int ret;
-	struct file *filp;
-
-	ret = get_unused_fd_flags(0);
-	if (ret < 0)
-		return ret;
-
 	/*
 	 * get references for dget and mntget, will be released
 	 * in error path of *_open().
 	 */
-	filp = dentry_open(path, O_RDONLY, current_cred());
+	FD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred()));
-	if (IS_ERR(filp)) {
+	if (fdf.err)
-		put_unused_fd(ret);
+		return fdf.err;
-		return PTR_ERR(filp);
+	fd_prepare_file(fdf)->f_op = &spufs_gang_fops;
-	}
+	return fd_publish(fdf);
-
-	filp->f_op = &spufs_gang_fops;
-	fd_install(ret, filp);
-	return ret;
 }
 
 static int spufs_create_gang(struct inode *inode,

arch/powerpc/platforms/pseries/papr-hvpipe.c

@@ -479,10 +479,7 @@ static const struct file_operations papr_hvpipe_handle_ops = {
 
 static int papr_hvpipe_dev_create_handle(u32 srcID)
 {
-	struct hvpipe_source_info *src_info;
+	struct hvpipe_source_info *src_info __free(kfree) = NULL;
-	struct file *file;
-	long err;
-	int fd;
 
 	spin_lock(&hvpipe_src_list_lock);
 	/*
@@ -506,20 +503,13 @@ static int papr_hvpipe_dev_create_handle(u32 srcID)
 	src_info->tsk = current;
 	init_waitqueue_head(&src_info->recv_wqh);
 
-	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
-	if (fd < 0) {
+		   anon_inode_getfile("[papr-hvpipe]", &papr_hvpipe_handle_ops,
-		err = fd;
+				      (void *)src_info, O_RDWR));
-		goto free_buf;
+	if (fdf.err)
-	}
+		return fdf.err;
-
-	file = anon_inode_getfile("[papr-hvpipe]",
-			&papr_hvpipe_handle_ops, (void *)src_info,
-			O_RDWR);
-	if (IS_ERR(file)) {
-		err = PTR_ERR(file);
-		goto free_fd;
-	}
 
+	retain_and_null_ptr(src_info);
 	spin_lock(&hvpipe_src_list_lock);
 	/*
 	 * If two processes are executing ioctl() for the same
@@ -528,22 +518,11 @@ static int papr_hvpipe_dev_create_handle(u32 srcID)
 	 */
 	if (hvpipe_find_source(srcID)) {
 		spin_unlock(&hvpipe_src_list_lock);
-		err = -EALREADY;
+		return -EALREADY;
-		goto free_file;
 	}
 	list_add(&src_info->list, &hvpipe_src_list);
 	spin_unlock(&hvpipe_src_list_lock);
-
+	return fd_publish(fdf);
-	fd_install(fd, file);
-	return fd;
-
-free_file:
-	fput(file);
-free_fd:
-	put_unused_fd(fd);
-free_buf:
-	kfree(src_info);
-	return err;
 }
 
 /*

arch/powerpc/platforms/pseries/papr-platform-dump.c

@@ -303,8 +303,6 @@ static long papr_platform_dump_create_handle(u64 dump_tag)
 {
 	struct ibm_platform_dump_params *params;
 	u64 param_dump_tag;
-	struct file *file;
-	long err;
 	int fd;
 
 	/*
@@ -334,34 +332,22 @@ static long papr_platform_dump_create_handle(u64 dump_tag)
 	params->dump_tag_lo = (u32)(dump_tag & 0x00000000ffffffffULL);
 	params->status = RTAS_IBM_PLATFORM_DUMP_START;
 
-	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	fd = FD_ADD(O_RDONLY | O_CLOEXEC,
+		    anon_inode_getfile_fmode("[papr-platform-dump]",
+					     &papr_platform_dump_handle_ops,
+					     (void *)params, O_RDONLY,
+					     FMODE_LSEEK | FMODE_PREAD));
 	if (fd < 0) {
-		err = fd;
+		rtas_work_area_free(params->work_area);
-		goto free_area;
+		kfree(params);
+		return fd;
 	}
 
-	file = anon_inode_getfile_fmode("[papr-platform-dump]",
-				&papr_platform_dump_handle_ops,
-				(void *)params, O_RDONLY,
-				FMODE_LSEEK | FMODE_PREAD);
-	if (IS_ERR(file)) {
-		err = PTR_ERR(file);
-		goto put_fd;
-	}
-
-	fd_install(fd, file);
-
 	list_add(&params->list, &platform_dump_list);
 
 	pr_info("%s (%d) initiated platform dump for dump tag %llu\n",
 		current->comm, current->pid, dump_tag);
 	return fd;
-put_fd:
-	put_unused_fd(fd);
-free_area:
-	rtas_work_area_free(params->work_area);
-	kfree(params);
-	return err;
 }
 
 /*

arch/powerpc/platforms/pseries/papr-rtas-common.c

@@ -205,35 +205,18 @@ long papr_rtas_setup_file_interface(struct papr_rtas_sequence *seq,
 				char *name)
 {
 	const struct papr_rtas_blob *blob;
-	struct file *file;
-	long ret;
 	int fd;
 
 	blob = papr_rtas_retrieve(seq);
 	if (IS_ERR(blob))
 		return PTR_ERR(blob);
 
-	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	fd = FD_ADD(O_RDONLY | O_CLOEXEC,
-	if (fd < 0) {
+		   anon_inode_getfile_fmode(name, fops, (void *)blob, O_RDONLY,
-		ret = fd;
+					    FMODE_LSEEK | FMODE_PREAD));
-		goto free_blob;
+	if (fd < 0)
-	}
+		papr_rtas_blob_free(blob);
-
-	file = anon_inode_getfile_fmode(name, fops, (void *)blob,
-			O_RDONLY, FMODE_LSEEK | FMODE_PREAD);
-	if (IS_ERR(file)) {
-		ret = PTR_ERR(file);
-		goto put_fd;
-	}
-
-	fd_install(fd, file);
 	return fd;
-
-put_fd:
-	put_unused_fd(fd);
-free_blob:
-	papr_rtas_blob_free(blob);
-	return ret;
 }
 
 /*

drivers/dma-buf/dma-buf.c

@@ -768,18 +768,10 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_export, "DMA_BUF");
  */
 int dma_buf_fd(struct dma_buf *dmabuf, int flags)
 {
-	int fd;
-
 	if (!dmabuf || !dmabuf->file)
 		return -EINVAL;
 
-	fd = get_unused_fd_flags(flags);
+	return FD_ADD(flags, dmabuf->file);
-	if (fd < 0)
-		return fd;
-
-	fd_install(fd, dmabuf->file);
-
-	return fd;
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF");
 

drivers/gpio/gpiolib-cdev.c

@@ -298,12 +298,13 @@ static const struct file_operations linehandle_fileops = {
 #endif
 };
 
+DEFINE_FREE(linehandle_free, struct linehandle_state *, if (!IS_ERR_OR_NULL(_T)) linehandle_free(_T))
+
 static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 {
 	struct gpiohandle_request handlereq;
-	struct linehandle_state *lh;
+	struct linehandle_state *lh __free(linehandle_free) = NULL;
-	struct file *file;
+	int i, ret;
-	int fd, i, ret;
 	u32 lflags;
 
 	if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
@@ -327,10 +328,8 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 		lh->label = kstrndup(handlereq.consumer_label,
 				     sizeof(handlereq.consumer_label) - 1,
 				     GFP_KERNEL);
-		if (!lh->label) {
+		if (!lh->label)
-			ret = -ENOMEM;
+			return -ENOMEM;
-			goto out_free_lh;
-		}
 	}
 
 	lh->num_descs = handlereq.lines;
@@ -340,20 +339,18 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 		u32 offset = handlereq.lineoffsets[i];
 		struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);
 
-		if (IS_ERR(desc)) {
+		if (IS_ERR(desc))
-			ret = PTR_ERR(desc);
+			return PTR_ERR(desc);
-			goto out_free_lh;
-		}
 
 		ret = gpiod_request_user(desc, lh->label);
 		if (ret)
-			goto out_free_lh;
+			return ret;
 		lh->descs[i] = desc;
 		linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
 
 		ret = gpiod_set_transitory(desc, false);
 		if (ret < 0)
-			goto out_free_lh;
+			return ret;
 
 		/*
 		 * Lines have to be requested explicitly for input
@@ -364,11 +361,11 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 
 			ret = gpiod_direction_output_nonotify(desc, val);
 			if (ret)
-				goto out_free_lh;
+				return ret;
 		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
 			ret = gpiod_direction_input_nonotify(desc);
 			if (ret)
-				goto out_free_lh;
+				return ret;
 		}
 
 		gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
@@ -377,44 +374,23 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 			offset);
 	}
 
-	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
-	if (fd < 0) {
+		   anon_inode_getfile("gpio-linehandle", &linehandle_fileops,
-		ret = fd;
+				      lh, O_RDONLY | O_CLOEXEC));
-		goto out_free_lh;
+	if (fdf.err)
-	}
+		return fdf.err;
+	retain_and_null_ptr(lh);
 
-	file = anon_inode_getfile("gpio-linehandle",
+	handlereq.fd = fd_prepare_fd(fdf);
-				  &linehandle_fileops,
+	if (copy_to_user(ip, &handlereq, sizeof(handlereq)))
-				  lh,
-				  O_RDONLY | O_CLOEXEC);
-	if (IS_ERR(file)) {
-		ret = PTR_ERR(file);
-		goto out_put_unused_fd;
-	}
-
-	handlereq.fd = fd;
-	if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
-		/*
-		 * fput() will trigger the release() callback, so do not go onto
-		 * the regular error cleanup path here.
-		 */
-		fput(file);
-		put_unused_fd(fd);
 		return -EFAULT;
-	}
 
-	fd_install(fd, file);
+	fd_publish(fdf);
 
 	dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
 		lh->num_descs);
 
 	return 0;
-
-out_put_unused_fd:
-	put_unused_fd(fd);
-out_free_lh:
-	linehandle_free(lh);
-	return ret;
 }
 #endif /* CONFIG_GPIO_CDEV_V1 */
 

drivers/hv/mshv_root_main.c

@@ -1870,8 +1870,6 @@ mshv_ioctl_create_partition(void __user *user_arg, struct device *module_dev)
 	struct hv_partition_creation_properties creation_properties = {};
 	union hv_partition_isolation_properties isolation_properties = {};
 	struct mshv_partition *partition;
-	struct file *file;
-	int fd;
 	long ret;
 
 	if (copy_from_user(&args, user_arg, sizeof(args)))
@@ -1938,29 +1936,13 @@ mshv_ioctl_create_partition(void __user *user_arg, struct device *module_dev)
 		goto delete_partition;
 
 	ret = mshv_init_async_handler(partition);
-	if (ret)
+	if (!ret) {
-		goto remove_partition;
+		ret = FD_ADD(O_CLOEXEC, anon_inode_getfile("mshv_partition",
-
+							   &mshv_partition_fops,
-	fd = get_unused_fd_flags(O_CLOEXEC);
+							   partition, O_RDWR));
-	if (fd < 0) {
+		if (ret >= 0)
-		ret = fd;
+			return ret;
-		goto remove_partition;
 	}
-
-	file = anon_inode_getfile("mshv_partition", &mshv_partition_fops,
-				  partition, O_RDWR);
-	if (IS_ERR(file)) {
-		ret = PTR_ERR(file);
-		goto put_fd;
-	}
-
-	fd_install(fd, file);
-
-	return fd;
-
-put_fd:
-	put_unused_fd(fd);
-remove_partition:
 	remove_partition(partition);
 delete_partition:
 	hv_call_delete_partition(partition->pt_id);

drivers/media/mc/mc-request.c

@@ -282,8 +282,6 @@ EXPORT_SYMBOL_GPL(media_request_get_by_fd);
 int media_request_alloc(struct media_device *mdev, int *alloc_fd)
 {
 	struct media_request *req;
-	struct file *filp;
-	int fd;
 	int ret;
 
 	/* Either both are NULL or both are non-NULL */
@@ -297,19 +295,6 @@ int media_request_alloc(struct media_device *mdev, int *alloc_fd)
 	if (!req)
 		return -ENOMEM;
 
-	fd = get_unused_fd_flags(O_CLOEXEC);
-	if (fd < 0) {
-		ret = fd;
-		goto err_free_req;
-	}
-
-	filp = anon_inode_getfile("request", &request_fops, NULL, O_CLOEXEC);
-	if (IS_ERR(filp)) {
-		ret = PTR_ERR(filp);
-		goto err_put_fd;
-	}
-
-	filp->private_data = req;
 	req->mdev = mdev;
 	req->state = MEDIA_REQUEST_STATE_IDLE;
 	req->num_incomplete_objects = 0;
@@ -320,19 +305,24 @@ int media_request_alloc(struct media_device *mdev, int *alloc_fd)
 	req->updating_count = 0;
 	req->access_count = 0;
 
-	*alloc_fd = fd;
+	FD_PREPARE(fdf, O_CLOEXEC,
+		   anon_inode_getfile("request", &request_fops, NULL,
+				      O_CLOEXEC));
+	if (fdf.err) {
+		ret = fdf.err;
+		goto err_free_req;
+	}
+
+	fd_prepare_file(fdf)->private_data = req;
+
+	*alloc_fd = fd_publish(fdf);
 
 	snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d",
-		 atomic_inc_return(&mdev->request_id), fd);
+		 atomic_inc_return(&mdev->request_id), *alloc_fd);
 	dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);
 
-	fd_install(fd, filp);
-
 	return 0;
 
-err_put_fd:
-	put_unused_fd(fd);
-
 err_free_req:
 	if (mdev->ops->req_free)
 		mdev->ops->req_free(req);

drivers/misc/ntsync.c

@@ -721,21 +721,12 @@ static struct ntsync_obj *ntsync_alloc_obj(struct ntsync_device *dev,
 
 static int ntsync_obj_get_fd(struct ntsync_obj *obj)
 {
-	struct file *file;
+	FD_PREPARE(fdf, O_CLOEXEC,
-	int fd;
+		   anon_inode_getfile("ntsync", &ntsync_obj_fops, obj, O_RDWR));
-
+	if (fdf.err)
-	fd = get_unused_fd_flags(O_CLOEXEC);
+		return fdf.err;
-	if (fd < 0)
+	obj->file = fd_prepare_file(fdf);
-		return fd;
+	return fd_publish(fdf);
-	file = anon_inode_getfile("ntsync", &ntsync_obj_fops, obj, O_RDWR);
-	if (IS_ERR(file)) {
-		put_unused_fd(fd);
-		return PTR_ERR(file);
-	}
-	obj->file = file;
-	fd_install(fd, file);
-
-	return fd;
 }
 
 static int ntsync_create_sem(struct ntsync_device *dev, void __user *argp)

drivers/tty/pty.c

@@ -589,6 +589,23 @@ static inline void legacy_pty_init(void) { }
 #ifdef CONFIG_UNIX98_PTYS
 static struct cdev ptmx_cdev;
 
+static struct file *ptm_open_peer_file(struct file *master,
+				       struct tty_struct *tty, int flags)
+{
+	struct path path;
+	struct file *file;
+
+	/* Compute the slave's path */
+	path.mnt = devpts_mntget(master, tty->driver_data);
+	if (IS_ERR(path.mnt))
+		return ERR_CAST(path.mnt);
+	path.dentry = tty->link->driver_data;
+
+	file = dentry_open(&path, flags, current_cred());
+	mntput(path.mnt);
+	return file;
+}
+
 /**
  *	ptm_open_peer - open the peer of a pty
  *	@master: the open struct file of the ptmx device node
@@ -601,42 +618,10 @@ static struct cdev ptmx_cdev;
  */
 int ptm_open_peer(struct file *master, struct tty_struct *tty, int flags)
 {
-	int fd;
-	struct file *filp;
-	int retval = -EINVAL;
-	struct path path;
-
 	if (tty->driver != ptm_driver)
 		return -EIO;
 
-	fd = get_unused_fd_flags(flags);
+	return FD_ADD(flags, ptm_open_peer_file(master, tty, flags));
-	if (fd < 0) {
-		retval = fd;
-		goto err;
-	}
-
-	/* Compute the slave's path */
-	path.mnt = devpts_mntget(master, tty->driver_data);
-	if (IS_ERR(path.mnt)) {
-		retval = PTR_ERR(path.mnt);
-		goto err_put;
-	}
-	path.dentry = tty->link->driver_data;
-
-	filp = dentry_open(&path, flags, current_cred());
-	mntput(path.mnt);
-	if (IS_ERR(filp)) {
-		retval = PTR_ERR(filp);
-		goto err_put;
-	}
-
-	fd_install(fd, filp);
-	return fd;
-
-err_put:
-	put_unused_fd(fd);
-err:
-	return retval;
 }
 
 static int pty_unix98_ioctl(struct tty_struct *tty,

drivers/vfio/group.c

@@ -299,10 +299,8 @@ static int vfio_group_ioctl_get_device_fd(struct vfio_group *group,
 					  char __user *arg)
 {
 	struct vfio_device *device;
-	struct file *filep;
 	char *buf;
-	int fdno;
+	int fd;
-	int ret;
 
 	buf = strndup_user(arg, PAGE_SIZE);
 	if (IS_ERR(buf))
@@ -313,26 +311,10 @@ static int vfio_group_ioctl_get_device_fd(struct vfio_group *group,
 	if (IS_ERR(device))
 		return PTR_ERR(device);
 
-	fdno = get_unused_fd_flags(O_CLOEXEC);
+	fd = FD_ADD(O_CLOEXEC, vfio_device_open_file(device));
-	if (fdno < 0) {
+	if (fd < 0)
-		ret = fdno;
+		vfio_device_put_registration(device);
-		goto err_put_device;
+	return fd;
-	}
-
-	filep = vfio_device_open_file(device);
-	if (IS_ERR(filep)) {
-		ret = PTR_ERR(filep);
-		goto err_put_fdno;
-	}
-
-	fd_install(fdno, filep);
-	return fdno;
-
-err_put_fdno:
-	put_unused_fd(fdno);
-err_put_device:
-	vfio_device_put_registration(device);
-	return ret;
 }
 
 static int vfio_group_ioctl_get_status(struct vfio_group *group,

fs/anon_inodes.c

@@ -280,27 +280,8 @@ static int __anon_inode_getfd(const char *name,
 			      const struct inode *context_inode,
 			      bool make_inode)
 {
-	int error, fd;
+	return FD_ADD(flags, __anon_inode_getfile(name, fops, priv, flags,
-	struct file *file;
+						  context_inode, make_inode));
-
-	error = get_unused_fd_flags(flags);
-	if (error < 0)
-		return error;
-	fd = error;
-
-	file = __anon_inode_getfile(name, fops, priv, flags, context_inode,
-				    make_inode);
-	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;
 }
 
 /**

fs/autofs/dev-ioctl.c

@@ -231,32 +231,14 @@ static int test_by_type(const struct path *path, void *p)
  */
 static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)
 {
-	int err, fd;
+	struct path path __free(path_put) = {};
+	int err;
 
-	fd = get_unused_fd_flags(O_CLOEXEC);
+	err = find_autofs_mount(name, &path, test_by_dev, &devid);
-	if (likely(fd >= 0)) {
+	if (err)
-		struct file *filp;
+		return err;
-		struct path path;
 
-		err = find_autofs_mount(name, &path, test_by_dev, &devid);
+	return FD_ADD(O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred()));
-		if (err)
-			goto out;
-
-		filp = dentry_open(&path, O_RDONLY, current_cred());
-		path_put(&path);
-		if (IS_ERR(filp)) {
-			err = PTR_ERR(filp);
-			goto out;
-		}
-
-		fd_install(fd, filp);
-	}
-
-	return fd;
-
-out:
-	put_unused_fd(fd);
-	return err;
 }
 
 /* Open a file descriptor on an autofs mount point */

fs/eventfd.c

@@ -378,9 +378,7 @@ EXPORT_SYMBOL_GPL(eventfd_ctx_fileget);
 
 static int do_eventfd(unsigned int count, int flags)
 {
-	struct eventfd_ctx *ctx;
+	struct eventfd_ctx *ctx __free(kfree) = NULL;
-	struct file *file;
-	int fd;
 
 	/* Check the EFD_* constants for consistency.  */
 	BUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC);
@@ -398,26 +396,19 @@ static int do_eventfd(unsigned int count, int flags)
 	init_waitqueue_head(&ctx->wqh);
 	ctx->count = count;
 	ctx->flags = flags;
-	ctx->id = ida_alloc(&eventfd_ida, GFP_KERNEL);
 
 	flags &= EFD_SHARED_FCNTL_FLAGS;
 	flags |= O_RDWR;
-	fd = get_unused_fd_flags(flags);
-	if (fd < 0)
-		goto err;
 
-	file = anon_inode_getfile_fmode("[eventfd]", &eventfd_fops,
+	FD_PREPARE(fdf, flags,
-					ctx, flags, FMODE_NOWAIT);
+		   anon_inode_getfile_fmode("[eventfd]", &eventfd_fops, ctx,
-	if (IS_ERR(file)) {
+					    flags, FMODE_NOWAIT));
-		put_unused_fd(fd);
+	if (fdf.err)
-		fd = PTR_ERR(file);
+		return fdf.err;
-		goto err;
+
-	}
+	ctx->id = ida_alloc(&eventfd_ida, GFP_KERNEL);
-	fd_install(fd, file);
+	retain_and_null_ptr(ctx);
-	return fd;
+	return fd_publish(fdf);
-err:
-	eventfd_free_ctx(ctx);
-	return fd;
 }
 
 SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)

fs/eventpoll.c

@@ -2165,9 +2165,8 @@ static void clear_tfile_check_list(void)
  */
 static int do_epoll_create(int flags)
 {
-	int error, fd;
+	int error;
-	struct eventpoll *ep = NULL;
+	struct eventpoll *ep;
-	struct file *file;
 
 	/* Check the EPOLL_* constant for consistency.  */
 	BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC);
@@ -2184,26 +2183,15 @@ static int do_epoll_create(int flags)
 	 * Creates all the items needed to setup an eventpoll file. That is,
 	 * a file structure and a free file descriptor.
 	 */
-	fd = get_unused_fd_flags(O_RDWR | (flags & O_CLOEXEC));
+	FD_PREPARE(fdf, O_RDWR | (flags & O_CLOEXEC),
-	if (fd < 0) {
+		   anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep,
-		error = fd;
+				      O_RDWR | (flags & O_CLOEXEC)));
-		goto out_free_ep;
+	if (fdf.err) {
+		ep_clear_and_put(ep);
+		return fdf.err;
 	}
-	file = anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep,
+	ep->file = fd_prepare_file(fdf);
-				 O_RDWR | (flags & O_CLOEXEC));
+	return fd_publish(fdf);
-	if (IS_ERR(file)) {
-		error = PTR_ERR(file);
-		goto out_free_fd;
-	}
-	ep->file = file;
-	fd_install(fd, file);
-	return fd;
-
-out_free_fd:
-	put_unused_fd(fd);
-out_free_ep:
-	ep_clear_and_put(ep);
-	return error;
 }
 
 SYSCALL_DEFINE1(epoll_create1, int, flags)

fs/exec.c

@@ -1280,10 +1280,9 @@ int begin_new_exec(struct linux_binprm * bprm)
 
 	/* Pass the opened binary to the interpreter. */
 	if (bprm->have_execfd) {
-		retval = get_unused_fd_flags(0);
+		retval = FD_ADD(0, bprm->executable);
 		if (retval < 0)
 			goto out_unlock;
-		fd_install(retval, bprm->executable);
 		bprm->executable = NULL;
 		bprm->execfd = retval;
 	}

fs/fhandle.c

@@ -404,32 +404,28 @@ static int handle_to_path(int mountdirfd, struct file_handle __user *ufh,
 	return retval;
 }
 
+static struct file *file_open_handle(struct path *path, int open_flag)
+{
+	const struct export_operations *eops;
+
+	eops = path->mnt->mnt_sb->s_export_op;
+	if (eops->open)
+		return eops->open(path, open_flag);
+
+	return file_open_root(path, "", open_flag, 0);
+}
+
 static long do_handle_open(int mountdirfd, struct file_handle __user *ufh,
 			   int open_flag)
 {
-	long retval = 0;
+	long retval;
 	struct path path __free(path_put) = {};
-	struct file *file;
-	const struct export_operations *eops;
 
 	retval = handle_to_path(mountdirfd, ufh, &path, open_flag);
 	if (retval)
 		return retval;
 
-	CLASS(get_unused_fd, fd)(open_flag);
+	return FD_ADD(open_flag, file_open_handle(&path, open_flag));
-	if (fd < 0)
-		return fd;
-
-	eops = path.mnt->mnt_sb->s_export_op;
-	if (eops->open)
-		file = eops->open(&path, open_flag);
-	else
-		file = file_open_root(&path, "", open_flag, 0);
-	if (IS_ERR(file))
-		return PTR_ERR(file);
-
-	fd_install(fd, file);
-	return take_fd(fd);
 }
 
 /**

fs/file.c

@@ -1380,28 +1380,25 @@ int replace_fd(unsigned fd, struct file *file, unsigned flags)
  */
 int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)
 {
-	int new_fd;
 	int error;
 
 	error = security_file_receive(file);
 	if (error)
 		return error;
 
-	new_fd = get_unused_fd_flags(o_flags);
+	FD_PREPARE(fdf, o_flags, file);
-	if (new_fd < 0)
+	if (fdf.err)
-		return new_fd;
+		return fdf.err;
+	get_file(file);
 
 	if (ufd) {
-		error = put_user(new_fd, ufd);
+		error = put_user(fd_prepare_fd(fdf), ufd);
-		if (error) {
+		if (error)
-			put_unused_fd(new_fd);
 			return error;
-		}
 	}
 
-	fd_install(new_fd, get_file(file));
+	__receive_sock(fd_prepare_file(fdf));
-	__receive_sock(file);
+	return fd_publish(fdf);
-	return new_fd;
 }
 EXPORT_SYMBOL_GPL(receive_fd);
 

fs/namespace.c

@@ -3100,19 +3100,7 @@ static struct file *vfs_open_tree(int dfd, const char __user *filename, unsigned
 
 SYSCALL_DEFINE3(open_tree, int, dfd, const char __user *, filename, unsigned, flags)
 {
-	int fd;
+	return FD_ADD(flags, vfs_open_tree(dfd, filename, flags));
-	struct file *file __free(fput) = NULL;
-
-	file = vfs_open_tree(dfd, filename, flags);
-	if (IS_ERR(file))
-		return PTR_ERR(file);
-
-	fd = get_unused_fd_flags(flags & O_CLOEXEC);
-	if (fd < 0)
-		return fd;
-
-	fd_install(fd, no_free_ptr(file));
-	return fd;
 }
 
 /*
@@ -4281,10 +4269,10 @@ static unsigned int attr_flags_to_mnt_flags(u64 attr_flags)
 SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,
 		unsigned int, attr_flags)
 {
+	struct path new_path __free(path_put) = {};
 	struct mnt_namespace *ns;
 	struct fs_context *fc;
-	struct file *file;
+	struct vfsmount *new_mnt;
-	struct path newmount;
 	struct mount *mnt;
 	unsigned int mnt_flags = 0;
 	long ret;
@@ -4322,35 +4310,36 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,
 
 	fc = fd_file(f)->private_data;
 
-	ret = mutex_lock_interruptible(&fc->uapi_mutex);
+	ACQUIRE(mutex_intr, uapi_mutex)(&fc->uapi_mutex);
-	if (ret < 0)
+	ret = ACQUIRE_ERR(mutex_intr, &uapi_mutex);
+	if (ret)
 		return ret;
 
 	/* There must be a valid superblock or we can't mount it */
 	ret = -EINVAL;
 	if (!fc->root)
-		goto err_unlock;
+		return ret;
 
 	ret = -EPERM;
 	if (mount_too_revealing(fc->root->d_sb, &mnt_flags)) {
 		errorfcp(fc, "VFS", "Mount too revealing");
-		goto err_unlock;
+		return ret;
 	}
 
 	ret = -EBUSY;
 	if (fc->phase != FS_CONTEXT_AWAITING_MOUNT)
-		goto err_unlock;
+		return ret;
 
 	if (fc->sb_flags & SB_MANDLOCK)
 		warn_mandlock();
 
-	newmount.mnt = vfs_create_mount(fc);
+	new_mnt = vfs_create_mount(fc);
-	if (IS_ERR(newmount.mnt)) {
+	if (IS_ERR(new_mnt))
-		ret = PTR_ERR(newmount.mnt);
+		return PTR_ERR(new_mnt);
-		goto err_unlock;
+	new_mnt->mnt_flags = mnt_flags;
-	}
+
-	newmount.dentry = dget(fc->root);
+	new_path.dentry = dget(fc->root);
-	newmount.mnt->mnt_flags = mnt_flags;
+	new_path.mnt = new_mnt;
 
 	/* We've done the mount bit - now move the file context into more or
 	 * less the same state as if we'd done an fspick().  We don't want to
@@ -4360,38 +4349,27 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,
 	vfs_clean_context(fc);
 
 	ns = alloc_mnt_ns(current->nsproxy->mnt_ns->user_ns, true);
-	if (IS_ERR(ns)) {
+	if (IS_ERR(ns))
-		ret = PTR_ERR(ns);
+		return PTR_ERR(ns);
-		goto err_path;
+	mnt = real_mount(new_path.mnt);
-	}
-	mnt = real_mount(newmount.mnt);
 	ns->root = mnt;
 	ns->nr_mounts = 1;
 	mnt_add_to_ns(ns, mnt);
-	mntget(newmount.mnt);
+	mntget(new_path.mnt);
 
-	/* Attach to an apparent O_PATH fd with a note that we need to unmount
+	FD_PREPARE(fdf, (flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,
-	 * it, not just simply put it.
+		   dentry_open(&new_path, O_PATH, fc->cred));
-	 */
+	if (fdf.err) {
-	file = dentry_open(&newmount, O_PATH, fc->cred);
+		dissolve_on_fput(new_path.mnt);
-	if (IS_ERR(file)) {
+		return fdf.err;
-		dissolve_on_fput(newmount.mnt);
-		ret = PTR_ERR(file);
-		goto err_path;
 	}
-	file->f_mode |= FMODE_NEED_UNMOUNT;
 
-	ret = get_unused_fd_flags((flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0);
+	/*
-	if (ret >= 0)
+	 * Attach to an apparent O_PATH fd with a note that we
-		fd_install(ret, file);
+	 * need to unmount it, not just simply put it.
-	else
+	 */
-		fput(file);
+	fd_prepare_file(fdf)->f_mode |= FMODE_NEED_UNMOUNT;
-
+	return fd_publish(fdf);
-err_path:
-	path_put(&newmount);
-err_unlock:
-	mutex_unlock(&fc->uapi_mutex);
-	return ret;
 }
 
 static inline int vfs_move_mount(const struct path *from_path,
@@ -5033,19 +5011,17 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user *, filename,
 		unsigned, flags, struct mount_attr __user *, uattr,
 		size_t, usize)
 {
-	struct file __free(fput) *file = NULL;
-	int fd;
-
 	if (!uattr && usize)
 		return -EINVAL;
 
-	file = vfs_open_tree(dfd, filename, flags);
+	FD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags));
-	if (IS_ERR(file))
+	if (fdf.err)
-		return PTR_ERR(file);
+		return fdf.err;
 
 	if (uattr) {
-		int ret;
 		struct mount_kattr kattr = {};
+		struct file *file = fd_prepare_file(fdf);
+		int ret;
 
 		if (flags & OPEN_TREE_CLONE)
 			kattr.kflags = MOUNT_KATTR_IDMAP_REPLACE;
@@ -5061,12 +5037,7 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user *, filename,
 			return ret;
 	}
 
-	fd = get_unused_fd_flags(flags & O_CLOEXEC);
+	return fd_publish(fdf);
-	if (fd < 0)
-		return fd;
-
-	fd_install(fd, no_free_ptr(file));
-	return fd;
 }
 
 int show_path(struct seq_file *m, struct dentry *root)

fs/notify/fanotify/fanotify_user.c

@@ -1597,16 +1597,20 @@ static struct hlist_head *fanotify_alloc_merge_hash(void)
 	return hash;
 }
 
+DEFINE_CLASS(fsnotify_group,
+	     struct fsnotify_group *,
+	     if (!IS_ERR_OR_NULL(_T)) fsnotify_destroy_group(_T),
+	     fsnotify_alloc_group(ops, flags),
+	     const struct fsnotify_ops *ops, int flags)
+
 /* fanotify syscalls */
 SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 {
 	struct user_namespace *user_ns = current_user_ns();
-	struct fsnotify_group *group;
 	int f_flags, fd;
 	unsigned int fid_mode = flags & FANOTIFY_FID_BITS;
 	unsigned int class = flags & FANOTIFY_CLASS_BITS;
 	unsigned int internal_flags = 0;
-	struct file *file;
 
 	pr_debug("%s: flags=%x event_f_flags=%x\n",
 		 __func__, flags, event_f_flags);
@@ -1690,36 +1694,29 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 	if (flags & FAN_NONBLOCK)
 		f_flags |= O_NONBLOCK;
 
-	/* fsnotify_alloc_group takes a ref.  Dropped in fanotify_release */
+	CLASS(fsnotify_group, group)(&fanotify_fsnotify_ops,
-	group = fsnotify_alloc_group(&fanotify_fsnotify_ops,
 				     FSNOTIFY_GROUP_USER);
-	if (IS_ERR(group)) {
+	/* fsnotify_alloc_group takes a ref.  Dropped in fanotify_release */
+	if (IS_ERR(group))
 		return PTR_ERR(group);
-	}
 
 	/* Enforce groups limits per user in all containing user ns */
 	group->fanotify_data.ucounts = inc_ucount(user_ns, current_euid(),
 						  UCOUNT_FANOTIFY_GROUPS);
-	if (!group->fanotify_data.ucounts) {
+	if (!group->fanotify_data.ucounts)
-		fd = -EMFILE;
+		return -EMFILE;
-		goto out_destroy_group;
-	}
 
 	group->fanotify_data.flags = flags | internal_flags;
 	group->memcg = get_mem_cgroup_from_mm(current->mm);
 	group->user_ns = get_user_ns(user_ns);
 
 	group->fanotify_data.merge_hash = fanotify_alloc_merge_hash();
-	if (!group->fanotify_data.merge_hash) {
+	if (!group->fanotify_data.merge_hash)
-		fd = -ENOMEM;
+		return -ENOMEM;
-		goto out_destroy_group;
-	}
 
 	group->overflow_event = fanotify_alloc_overflow_event();
-	if (unlikely(!group->overflow_event)) {
+	if (unlikely(!group->overflow_event))
-		fd = -ENOMEM;
+		return -ENOMEM;
-		goto out_destroy_group;
-	}
 
 	if (force_o_largefile())
 		event_f_flags |= O_LARGEFILE;
@@ -1738,8 +1735,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 		group->priority = FSNOTIFY_PRIO_PRE_CONTENT;
 		break;
 	default:
-		fd = -EINVAL;
+		return -EINVAL;
-		goto out_destroy_group;
 	}
 
 	BUILD_BUG_ON(!(FANOTIFY_ADMIN_INIT_FLAGS & FAN_UNLIMITED_QUEUE));
@@ -1750,27 +1746,15 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 	}
 
 	if (flags & FAN_ENABLE_AUDIT) {
-		fd = -EPERM;
 		if (!capable(CAP_AUDIT_WRITE))
-			goto out_destroy_group;
+			return -EPERM;
 	}
 
-	fd = get_unused_fd_flags(f_flags);
+	fd = FD_ADD(f_flags,
-	if (fd < 0)
+		    anon_inode_getfile_fmode("[fanotify]", &fanotify_fops,
-		goto out_destroy_group;
+					     group, f_flags, FMODE_NONOTIFY));
-
+	if (fd >= 0)
-	file = anon_inode_getfile_fmode("[fanotify]", &fanotify_fops, group,
+		retain_and_null_ptr(group);
-					f_flags, FMODE_NONOTIFY);
-	if (IS_ERR(file)) {
-		put_unused_fd(fd);
-		fd = PTR_ERR(file);
-		goto out_destroy_group;
-	}
-	fd_install(fd, file);
-	return fd;
-
-out_destroy_group:
-	fsnotify_destroy_group(group);
 	return fd;
 }
 

fs/nsfs.c

@@ -110,7 +110,6 @@ int ns_get_path(struct path *path, struct task_struct *task,
 int open_namespace(struct ns_common *ns)
 {
 	struct path path __free(path_put) = {};
-	struct file *f;
 	int err;
 
 	/* call first to consume reference */
@@ -118,16 +117,7 @@ int open_namespace(struct ns_common *ns)
 	if (err < 0)
 		return err;
 
-	CLASS(get_unused_fd, fd)(O_CLOEXEC);
+	return FD_ADD(O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred()));
-	if (fd < 0)
-		return fd;
-
-	f = dentry_open(&path, O_RDONLY, current_cred());
-	if (IS_ERR(f))
-		return PTR_ERR(f);
-
-	fd_install(fd, f);
-	return take_fd(fd);
 }
 
 int open_related_ns(struct ns_common *ns,
@@ -313,7 +303,6 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl,
 		struct mnt_ns_info kinfo = {};
 		struct mnt_ns_info __user *uinfo = (struct mnt_ns_info __user *)arg;
 		struct path path __free(path_put) = {};
-		struct file *f __free(fput) = NULL;
 		size_t usize = _IOC_SIZE(ioctl);
 
 		if (ns->ns_type != CLONE_NEWNS)
@@ -332,28 +321,18 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl,
 		if (ret)
 			return ret;
 
-		CLASS(get_unused_fd, fd)(O_CLOEXEC);
+		FD_PREPARE(fdf, O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred()));
-		if (fd < 0)
+		if (fdf.err)
-			return fd;
+			return fdf.err;
-
+		/*
-		f = dentry_open(&path, O_RDONLY, current_cred());
+		 * If @uinfo is passed return all information about the
-		if (IS_ERR(f))
+		 * mount namespace as well.
-			return PTR_ERR(f);
+		 */
-
+		ret = copy_ns_info_to_user(to_mnt_ns(ns), uinfo, usize, &kinfo);
-		if (uinfo) {
+		if (ret)
-			/*
+			return ret;
-			 * If @uinfo is passed return all information about the
+		ret = fd_publish(fdf);
-			 * mount namespace as well.
+		break;
-			 */
-			ret = copy_ns_info_to_user(to_mnt_ns(ns), uinfo, usize, &kinfo);
-			if (ret)
-				return ret;
-		}
-
-		/* Transfer reference of @f to caller's fdtable. */
-		fd_install(fd, no_free_ptr(f));
-		/* File descriptor is live so hand it off to the caller. */
-		return take_fd(fd);
 	}
 	default:
 		ret = -ENOTTY;

fs/open.c

@@ -1416,8 +1416,8 @@ static int do_sys_openat2(int dfd, const char __user *filename,
 			  struct open_how *how)
 {
 	struct open_flags op;
-	struct filename *tmp;
+	struct filename *tmp __free(putname) = NULL;
-	int err, fd;
+	int err;
 
 	err = build_open_flags(how, &op);
 	if (unlikely(err))
@@ -1427,18 +1427,7 @@ static int do_sys_openat2(int dfd, const char __user *filename,
 	if (IS_ERR(tmp))
 		return PTR_ERR(tmp);
 
-	fd = get_unused_fd_flags(how->flags);
+	return FD_ADD(how->flags, do_filp_open(dfd, tmp, &op));
-	if (likely(fd >= 0)) {
-		struct file *f = do_filp_open(dfd, tmp, &op);
-		if (IS_ERR(f)) {
-			put_unused_fd(fd);
-			fd = PTR_ERR(f);
-		} else {
-			fd_install(fd, f);
-		}
-	}
-	putname(tmp);
-	return fd;
 }
 
 int do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)

fs/signalfd.c

@@ -250,8 +250,6 @@ static const struct file_operations signalfd_fops = {
 
 static int do_signalfd4(int ufd, sigset_t *mask, int flags)
 {
-	struct signalfd_ctx *ctx;
-
 	/* Check the SFD_* constants for consistency.  */
 	BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC);
 	BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK);
@@ -263,7 +261,8 @@ static int do_signalfd4(int ufd, sigset_t *mask, int flags)
 	signotset(mask);
 
 	if (ufd == -1) {
-		struct file *file;
+		int fd;
+		struct signalfd_ctx *ctx __free(kfree) = NULL;
 
 		ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
 		if (!ctx)
@@ -271,22 +270,16 @@ static int do_signalfd4(int ufd, sigset_t *mask, int flags)
 
 		ctx->sigmask = *mask;
 
-		ufd = get_unused_fd_flags(flags & O_CLOEXEC);
+		fd = FD_ADD(flags & O_CLOEXEC,
-		if (ufd < 0) {
+			    anon_inode_getfile_fmode(
-			kfree(ctx);
+				    "[signalfd]", &signalfd_fops, ctx,
-			return ufd;
+				    O_RDWR | (flags & O_NONBLOCK), FMODE_NOWAIT));
-		}
+		if (fd >= 0)
-
+			retain_and_null_ptr(ctx);
-		file = anon_inode_getfile_fmode("[signalfd]", &signalfd_fops,
+		return fd;
-					ctx, O_RDWR | (flags & O_NONBLOCK),
-					FMODE_NOWAIT);
-		if (IS_ERR(file)) {
-			put_unused_fd(ufd);
-			kfree(ctx);
-			return PTR_ERR(file);
-		}
-		fd_install(ufd, file);
 	} else {
+		struct signalfd_ctx *ctx;
+
 		CLASS(fd, f)(ufd);
 		if (fd_empty(f))
 			return -EBADF;

fs/timerfd.c

@@ -393,9 +393,8 @@ static const struct file_operations timerfd_fops = {
 
 SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 {
-	int ufd;
+	struct timerfd_ctx *ctx __free(kfree) = NULL;
-	struct timerfd_ctx *ctx;
+	int ret;
-	struct file *file;
 
 	/* Check the TFD_* constants for consistency.  */
 	BUILD_BUG_ON(TFD_CLOEXEC != O_CLOEXEC);
@@ -432,23 +431,13 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 
 	ctx->moffs = ktime_mono_to_real(0);
 
-	ufd = get_unused_fd_flags(flags & TFD_SHARED_FCNTL_FLAGS);
+	ret = FD_ADD(flags & TFD_SHARED_FCNTL_FLAGS,
-	if (ufd < 0) {
+		     anon_inode_getfile_fmode("[timerfd]", &timerfd_fops, ctx,
-		kfree(ctx);
+					      O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS),
-		return ufd;
+					      FMODE_NOWAIT));
-	}
+	if (ret >= 0)
-
+		retain_and_null_ptr(ctx);
-	file = anon_inode_getfile_fmode("[timerfd]", &timerfd_fops, ctx,
+	return ret;
-			    O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS),
-			    FMODE_NOWAIT);
-	if (IS_ERR(file)) {
-		put_unused_fd(ufd);
-		kfree(ctx);
-		return PTR_ERR(file);
-	}
-
-	fd_install(ufd, file);
-	return ufd;
 }
 
 static int do_timerfd_settime(int ufd, int flags, 

fs/userfaultfd.c

@@ -2111,9 +2111,7 @@ static void init_once_userfaultfd_ctx(void *mem)
 
 static int new_userfaultfd(int flags)
 {
-	struct userfaultfd_ctx *ctx;
+	struct userfaultfd_ctx *ctx __free(kfree) = NULL;
-	struct file *file;
-	int fd;
 
 	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);
+	FD_PREPARE(fdf, flags & UFFD_SHARED_FCNTL_FLAGS,
-	if (fd < 0)
+		   anon_inode_create_getfile("[userfaultfd]", &userfaultfd_fops, ctx,
-		goto err_out;
+					     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_prepare_file(fdf)->f_mode |= FMODE_NOWAIT;
-	fd_install(fd, file);
+	retain_and_null_ptr(ctx);
-	return fd;
+	return fd_publish(fdf);
-err_out:
-	kmem_cache_free(userfaultfd_ctx_cachep, ctx);
-	return fd;
 }
 
 static inline bool userfaultfd_syscall_allowed(int flags)

fs/xfs/xfs_handle.c

@@ -233,14 +233,11 @@ xfs_open_by_handle(
 	xfs_fsop_handlereq_t	*hreq)
 {
 	const struct cred	*cred = current_cred();
-	int			error;
-	int			fd;
 	int			permflag;
-	struct file		*filp;
 	struct inode		*inode;
 	struct dentry		*dentry;
 	fmode_t			fmode;
-	struct path		path;
+	struct path		path __free(path_put) = {};
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
@@ -249,12 +246,11 @@ xfs_open_by_handle(
 	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
 	inode = d_inode(dentry);
+	path.dentry = dentry;
 
 	/* Restrict xfs_open_by_handle to directories & regular files. */
-	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))) {
+	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
-		error = -EPERM;
+		return -EPERM;
-		goto out_dput;
-	}
 
 #if BITS_PER_LONG != 32
 	hreq->oflags |= O_LARGEFILE;
@@ -263,48 +259,30 @@ xfs_open_by_handle(
 	permflag = hreq->oflags;
 	fmode = OPEN_FMODE(permflag);
 	if ((!(permflag & O_APPEND) || (permflag & O_TRUNC)) &&
-	    (fmode & FMODE_WRITE) && IS_APPEND(inode)) {
+	    (fmode & FMODE_WRITE) && IS_APPEND(inode))
-		error = -EPERM;
+		return -EPERM;
-		goto out_dput;
-	}
 
-	if ((fmode & FMODE_WRITE) && IS_IMMUTABLE(inode)) {
+	if ((fmode & FMODE_WRITE) && IS_IMMUTABLE(inode))
-		error = -EPERM;
+		return -EPERM;
-		goto out_dput;
-	}
 
 	/* Can't write directories. */
-	if (S_ISDIR(inode->i_mode) && (fmode & FMODE_WRITE)) {
+	if (S_ISDIR(inode->i_mode) && (fmode & FMODE_WRITE))
-		error = -EISDIR;
+		return -EISDIR;
-		goto out_dput;
-	}
 
-	fd = get_unused_fd_flags(0);
+	path.mnt = mntget(parfilp->f_path.mnt);
-	if (fd < 0) {
-		error = fd;
-		goto out_dput;
-	}
 
-	path.mnt = parfilp->f_path.mnt;
+	FD_PREPARE(fdf, 0, dentry_open(&path, hreq->oflags, cred));
-	path.dentry = dentry;
+	if (fdf.err)
-	filp = dentry_open(&path, hreq->oflags, cred);
+		return fdf.err;
-	dput(dentry);
-	if (IS_ERR(filp)) {
-		put_unused_fd(fd);
-		return PTR_ERR(filp);
-	}
 
 	if (S_ISREG(inode->i_mode)) {
+		struct file *filp = fd_prepare_file(fdf);
+
 		filp->f_flags |= O_NOATIME;
 		filp->f_mode |= FMODE_NOCMTIME;
 	}
 
-	fd_install(fd, filp);
+	return fd_publish(fdf);
-	return fd;
-
- out_dput:
-	dput(dentry);
-	return error;
 }
 
 int

include/linux/cleanup.h

@@ -261,6 +261,10 @@ const volatile void * __must_check_fn(const volatile void *val)
  * CLASS(name, var)(args...):
  *	declare the variable @var as an instance of the named class
  *
+ * CLASS_INIT(name, var, init_expr):
+ *	declare the variable @var as an instance of the named class with
+ *	custom initialization expression.
+ *
  * Ex.
  *
  * DEFINE_CLASS(fdget, struct fd, fdput(_T), fdget(fd), int fd)
@@ -290,6 +294,9 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \
 	class_##_name##_t var __cleanup(class_##_name##_destructor) =	\
 		class_##_name##_constructor
 
+#define CLASS_INIT(_name, _var, _init_expr)                             \
+        class_##_name##_t _var __cleanup(class_##_name##_destructor) = (_init_expr)
+
 #define __scoped_class(_name, var, _label, args...)        \
 	for (CLASS(_name, var)(args); ; ({ goto _label; })) \
 		if (0) {                                   \

include/linux/file.h

@@ -127,4 +127,130 @@ extern void __fput_sync(struct file *);
 
 extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
 
+/*
+ * fd_prepare: Combined fd + file allocation cleanup class.
+ * @err: Error code to indicate if allocation succeeded.
+ * @__fd: Allocated fd (may not be accessed directly)
+ * @__file: Allocated struct file pointer (may not be accessed directly)
+ *
+ * Allocates an fd and a file together. On error paths, automatically cleans
+ * up whichever resource was successfully allocated. Allows flexible file
+ * allocation with different functions per usage.
+ *
+ * Do not use directly.
+ */
+struct fd_prepare {
+	s32 err;
+	s32 __fd; /* do not access directly */
+	struct file *__file; /* do not access directly */
+};
+
+/* Typedef for fd_prepare cleanup guards. */
+typedef struct fd_prepare class_fd_prepare_t;
+
+/*
+ * Accessors for fd_prepare class members.
+ * _Generic() is used for zero-cost type safety.
+ */
+#define fd_prepare_fd(_fdf) \
+	(_Generic((_fdf), struct fd_prepare: (_fdf).__fd))
+
+#define fd_prepare_file(_fdf) \
+	(_Generic((_fdf), struct fd_prepare: (_fdf).__file))
+
+/* Do not use directly. */
+static inline void class_fd_prepare_destructor(const struct fd_prepare *fdf)
+{
+	if (unlikely(fdf->err)) {
+		if (likely(fdf->__fd >= 0))
+			put_unused_fd(fdf->__fd);
+		if (unlikely(!IS_ERR_OR_NULL(fdf->__file)))
+			fput(fdf->__file);
+	}
+}
+
+/* Do not use directly. */
+static inline int class_fd_prepare_lock_err(const struct fd_prepare *fdf)
+{
+	if (unlikely(fdf->err))
+		return fdf->err;
+	if (unlikely(fdf->__fd < 0))
+		return fdf->__fd;
+	if (unlikely(IS_ERR(fdf->__file)))
+		return PTR_ERR(fdf->__file);
+	if (unlikely(!fdf->__file))
+		return -ENOMEM;
+	return 0;
+}
+
+/*
+ * __FD_PREPARE_INIT - Helper to initialize fd_prepare class.
+ * @_fd_flags: flags for get_unused_fd_flags()
+ * @_file_owned: expression that returns struct file *
+ *
+ * Returns a struct fd_prepare with fd, file, and err set.
+ * If fd allocation fails, fd will be negative and err will be set. If
+ * fd succeeds but file_init_expr fails, file will be ERR_PTR and err
+ * will be set. The err field is the single source of truth for error
+ * checking.
+ */
+#define __FD_PREPARE_INIT(_fd_flags, _file_owned)                 \
+	({                                                        \
+		struct fd_prepare fdf = {                         \
+			.__fd = get_unused_fd_flags((_fd_flags)), \
+		};                                                \
+		if (likely(fdf.__fd >= 0))                        \
+			fdf.__file = (_file_owned);               \
+		fdf.err = ACQUIRE_ERR(fd_prepare, &fdf);          \
+		fdf;                                              \
+	})
+
+/*
+ * FD_PREPARE - Macro to declare and initialize an fd_prepare variable.
+ *
+ * Declares and initializes an fd_prepare variable with automatic
+ * cleanup. No separate scope required - cleanup happens when variable
+ * goes out of scope.
+ *
+ * @_fdf: name of struct fd_prepare variable to define
+ * @_fd_flags: flags for get_unused_fd_flags()
+ * @_file_owned: struct file to take ownership of (can be expression)
+ */
+#define FD_PREPARE(_fdf, _fd_flags, _file_owned) \
+	CLASS_INIT(fd_prepare, _fdf, __FD_PREPARE_INIT(_fd_flags, _file_owned))
+
+/*
+ * fd_publish - Publish prepared fd and file to the fd table.
+ * @_fdf: struct fd_prepare variable
+ */
+#define fd_publish(_fdf)                                       \
+	({                                                     \
+		struct fd_prepare *fdp = &(_fdf);              \
+		VFS_WARN_ON_ONCE(fdp->err);                    \
+		VFS_WARN_ON_ONCE(fdp->__fd < 0);               \
+		VFS_WARN_ON_ONCE(IS_ERR_OR_NULL(fdp->__file)); \
+		fd_install(fdp->__fd, fdp->__file);            \
+		fdp->__fd;                                     \
+	})
+
+/* Do not use directly. */
+#define __FD_ADD(_fdf, _fd_flags, _file_owned)            \
+	({                                                \
+		FD_PREPARE(_fdf, _fd_flags, _file_owned); \
+		s32 ret = _fdf.err;                       \
+		if (likely(!ret))                         \
+			ret = fd_publish(_fdf);           \
+		ret;                                      \
+	})
+
+/*
+ * FD_ADD - Allocate and install an fd and file in one step.
+ * @_fd_flags: flags for get_unused_fd_flags()
+ * @_file_owned: struct file to take ownership of
+ *
+ * Returns the allocated fd number, or negative error code on failure.
+ */
+#define FD_ADD(_fd_flags, _file_owned) \
+	__FD_ADD(__UNIQUE_ID(fd_prepare), _fd_flags, _file_owned)
+
 #endif /* __LINUX_FILE_H */

io_uring/mock_file.c

@@ -211,10 +211,9 @@ static int io_create_mock_file(struct io_uring_cmd *cmd, unsigned int issue_flag
 	const struct file_operations *fops = &io_mock_fops;
 	const struct io_uring_sqe *sqe = cmd->sqe;
 	struct io_uring_mock_create mc, __user *uarg;
-	struct io_mock_file *mf = NULL;
+	struct file *file;
-	struct file *file = NULL;
+	struct io_mock_file *mf __free(kfree) = NULL;
 	size_t uarg_size;
-	int fd = -1, ret;
 
 	/*
 	 * It's a testing only driver that allows exercising edge cases
@@ -246,10 +245,6 @@ static int io_create_mock_file(struct io_uring_cmd *cmd, unsigned int issue_flag
 	if (!mf)
 		return -ENOMEM;
 
-	ret = fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
-	if (fd < 0)
-		goto fail;
-
 	init_waitqueue_head(&mf->poll_wq);
 	mf->size = mc.file_size;
 	mf->rw_delay_ns = mc.rw_delay_ns;
@@ -258,33 +253,25 @@ static int io_create_mock_file(struct io_uring_cmd *cmd, unsigned int issue_flag
 		mf->pollable = true;
 	}
 
-	file = anon_inode_create_getfile("[io_uring_mock]", fops,
+	FD_PREPARE(fdf, O_RDWR | O_CLOEXEC,
-					 mf, O_RDWR | O_CLOEXEC, NULL);
+		   anon_inode_create_getfile("[io_uring_mock]", fops, mf,
-	if (IS_ERR(file)) {
+					     O_RDWR | O_CLOEXEC, NULL));
-		ret = PTR_ERR(file);
+	if (fdf.err)
-		goto fail;
+		return fdf.err;
-	}
 
-	file->f_mode |= FMODE_READ | FMODE_CAN_READ |
+	retain_and_null_ptr(mf);
-			FMODE_WRITE | FMODE_CAN_WRITE |
+	file = fd_prepare_file(fdf);
-			FMODE_LSEEK;
+	file->f_mode |= FMODE_READ | FMODE_CAN_READ | FMODE_WRITE |
+			FMODE_CAN_WRITE | FMODE_LSEEK;
 	if (mc.flags & IORING_MOCK_CREATE_F_SUPPORT_NOWAIT)
 		file->f_mode |= FMODE_NOWAIT;
 
-	mc.out_fd = fd;
+	mc.out_fd = fd_prepare_fd(fdf);
-	if (copy_to_user(uarg, &mc, uarg_size)) {
+	if (copy_to_user(uarg, &mc, uarg_size))
-		fput(file);
+		return -EFAULT;
-		ret = -EFAULT;
-		goto fail;
-	}
 
-	fd_install(fd, file);
+	fd_publish(fdf);
 	return 0;
-fail:
-	if (fd >= 0)
-		put_unused_fd(fd);
-	kfree(mf);
-	return ret;
 }
 
 static int io_probe_mock(struct io_uring_cmd *cmd)

ipc/mqueue.c

@@ -892,15 +892,35 @@ static int prepare_open(struct dentry *dentry, int oflag, int ro,
 	return inode_permission(&nop_mnt_idmap, d_inode(dentry), acc);
 }
 
+static struct file *mqueue_file_open(struct filename *name,
+				     struct vfsmount *mnt, int oflag, bool ro,
+				     umode_t mode, struct mq_attr *attr)
+{
+	struct dentry *dentry;
+	struct file *file;
+	int ret;
+
+	dentry = start_creating_noperm(mnt->mnt_root, &QSTR(name->name));
+	if (IS_ERR(dentry))
+		return ERR_CAST(dentry);
+
+	ret = prepare_open(dentry, oflag, ro, mode, name, attr);
+	file = ERR_PTR(ret);
+	if (!ret) {
+		const struct path path = { .mnt = mnt, .dentry = dentry };
+		file = dentry_open(&path, oflag, current_cred());
+	}
+
+	end_creating(dentry);
+	return file;
+}
+
 static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
 		      struct mq_attr *attr)
 {
+	struct filename *name __free(putname) = NULL;;
 	struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
-	struct dentry *root = mnt->mnt_root;
+	int fd, ro;
-	struct filename *name;
-	struct path path;
-	int fd, error;
-	int ro;
 
 	audit_mq_open(oflag, mode, attr);
 
@@ -908,35 +928,10 @@ static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
 	if (IS_ERR(name))
 		return PTR_ERR(name);
 
-	fd = get_unused_fd_flags(O_CLOEXEC);
-	if (fd < 0)
-		goto out_putname;
-
 	ro = mnt_want_write(mnt);	/* we'll drop it in any case */
-	path.dentry = start_creating_noperm(root, &QSTR(name->name));
+	fd = FD_ADD(O_CLOEXEC, mqueue_file_open(name, mnt, oflag, ro, mode, attr));
-	if (IS_ERR(path.dentry)) {
-		error = PTR_ERR(path.dentry);
-		goto out_putfd;
-	}
-	path.mnt = mnt;
-	error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
-	if (!error) {
-		struct file *file = dentry_open(&path, oflag, current_cred());
-		if (!IS_ERR(file))
-			fd_install(fd, file);
-		else
-			error = PTR_ERR(file);
-	}
-out_putfd:
-	if (error) {
-		put_unused_fd(fd);
-		fd = error;
-	}
-	end_creating(path.dentry);
 	if (!ro)
 		mnt_drop_write(mnt);
-out_putname:
-	putname(name);
 	return fd;
 }
 

kernel/bpf/bpf_iter.c

@@ -634,37 +634,24 @@ static int prepare_seq_file(struct file *file, struct bpf_iter_link *link)
 int bpf_iter_new_fd(struct bpf_link *link)
 {
 	struct bpf_iter_link *iter_link;
-	struct file *file;
 	unsigned int flags;
-	int err, fd;
+	int err;
 
 	if (link->ops != &bpf_iter_link_lops)
 		return -EINVAL;
 
 	flags = O_RDONLY | O_CLOEXEC;
-	fd = get_unused_fd_flags(flags);
-	if (fd < 0)
-		return fd;
 
-	file = anon_inode_getfile("bpf_iter", &bpf_iter_fops, NULL, flags);
+	FD_PREPARE(fdf, flags, anon_inode_getfile("bpf_iter", &bpf_iter_fops, NULL, flags));
-	if (IS_ERR(file)) {
+	if (fdf.err)
-		err = PTR_ERR(file);
+		return fdf.err;
-		goto free_fd;
-	}
 
 	iter_link = container_of(link, struct bpf_iter_link, link);
-	err = prepare_seq_file(file, iter_link);
+	err = prepare_seq_file(fd_prepare_file(fdf), iter_link);
 	if (err)
-		goto free_file;
+		return err; /* Automatic cleanup handles fput */
 
-	fd_install(fd, file);
+	return fd_publish(fdf);
-	return fd;
-
-free_file:
-	fput(file);
-free_fd:
-	put_unused_fd(fd);
-	return err;
 }
 
 struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_stop)

kernel/bpf/token.c

@@ -110,16 +110,15 @@ const struct file_operations bpf_token_fops = {
 
 int bpf_token_create(union bpf_attr *attr)
 {
+	struct bpf_token *token __free(kfree) = NULL;
 	struct bpf_mount_opts *mnt_opts;
-	struct bpf_token *token = NULL;
 	struct user_namespace *userns;
 	struct inode *inode;
-	struct file *file;
 	CLASS(fd, f)(attr->token_create.bpffs_fd);
 	struct path path;
 	struct super_block *sb;
 	umode_t mode;
-	int err, fd;
+	int err;
 
 	if (fd_empty(f))
 		return -EBADF;
@@ -166,23 +165,20 @@ int bpf_token_create(union bpf_attr *attr)
 	inode->i_fop = &bpf_token_fops;
 	clear_nlink(inode); /* make sure it is unlinked */
 
-	file = alloc_file_pseudo(inode, path.mnt, BPF_TOKEN_INODE_NAME, O_RDWR, &bpf_token_fops);
+	FD_PREPARE(fdf, O_CLOEXEC,
-	if (IS_ERR(file)) {
+		   alloc_file_pseudo(inode, path.mnt, BPF_TOKEN_INODE_NAME,
-		iput(inode);
+				     O_RDWR, &bpf_token_fops));
-		return PTR_ERR(file);
+	if (fdf.err)
-	}
+		return fdf.err;
 
 	token = kzalloc(sizeof(*token), GFP_USER);
-	if (!token) {
+	if (!token)
-		err = -ENOMEM;
+		return -ENOMEM;
-		goto out_file;
-	}
 
 	atomic64_set(&token->refcnt, 1);
 
-	/* remember bpffs owning userns for future ns_capable() checks */
+	/* remember bpffs owning userns for future ns_capable() checks. */
-	token->userns = get_user_ns(userns);
+	token->userns = userns;
-
 	token->allowed_cmds = mnt_opts->delegate_cmds;
 	token->allowed_maps = mnt_opts->delegate_maps;
 	token->allowed_progs = mnt_opts->delegate_progs;
@@ -190,24 +186,11 @@ int bpf_token_create(union bpf_attr *attr)
 
 	err = security_bpf_token_create(token, attr, &path);
 	if (err)
-		goto out_token;
+		return err;
 
-	fd = get_unused_fd_flags(O_CLOEXEC);
+	get_user_ns(token->userns);
-	if (fd < 0) {
+	fd_prepare_file(fdf)->private_data = no_free_ptr(token);
-		err = fd;
+	return fd_publish(fdf);
-		goto out_token;
-	}
-
-	file->private_data = token;
-	fd_install(fd, file);
-
-	return fd;
-
-out_token:
-	bpf_token_free(token);
-out_file:
-	fput(file);
-	return err;
 }
 
 int bpf_token_get_info_by_fd(struct bpf_token *token,

mm/memfd.c

@@ -497,9 +497,9 @@ SYSCALL_DEFINE2(memfd_create,
 		const char __user *, uname,
 		unsigned int, flags)
 {
-	struct file *file;
+	char *name __free(kfree) = NULL;
-	int fd, error;
+	unsigned int fd_flags;
-	char *name;
+	int error;
 
 	error = sanitize_flags(&flags);
 	if (error < 0)
@@ -509,25 +509,6 @@ SYSCALL_DEFINE2(memfd_create,
 	if (IS_ERR(name))
 		return PTR_ERR(name);
 
-	fd = get_unused_fd_flags((flags & MFD_CLOEXEC) ? O_CLOEXEC : 0);
+	fd_flags = (flags & MFD_CLOEXEC) ? O_CLOEXEC : 0;
-	if (fd < 0) {
+	return FD_ADD(fd_flags, alloc_file(name, flags));
-		error = fd;
-		goto err_free_name;
-	}
-
-	file = alloc_file(name, flags);
-	if (IS_ERR(file)) {
-		error = PTR_ERR(file);
-		goto err_free_fd;
-	}
-
-	fd_install(fd, file);
-	kfree(name);
-	return fd;
-
-err_free_fd:
-	put_unused_fd(fd);
-err_free_name:
-	kfree(name);
-	return error;
 }

mm/secretmem.c

@@ -224,9 +224,6 @@ static struct file *secretmem_file_create(unsigned long flags)
 
 SYSCALL_DEFINE1(memfd_secret, unsigned int, flags)
 {
-	struct file *file;
-	int fd, err;
-
 	/* make sure local flags do not confict with global fcntl.h */
 	BUILD_BUG_ON(SECRETMEM_FLAGS_MASK & O_CLOEXEC);
 
@@ -238,22 +235,7 @@ SYSCALL_DEFINE1(memfd_secret, unsigned int, flags)
 	if (atomic_read(&secretmem_users) < 0)
 		return -ENFILE;
 
-	fd = get_unused_fd_flags(flags & O_CLOEXEC);
+	return FD_ADD(flags & O_CLOEXEC, secretmem_file_create(flags));
-	if (fd < 0)
-		return fd;
-
-	file = secretmem_file_create(flags);
-	if (IS_ERR(file)) {
-		err = PTR_ERR(file);
-		goto err_put_fd;
-	}
-
-	fd_install(fd, file);
-	return fd;
-
-err_put_fd:
-	put_unused_fd(fd);
-	return err;
 }
 
 static int secretmem_init_fs_context(struct fs_context *fc)

net/handshake/netlink.c

@@ -93,7 +93,7 @@ int handshake_nl_accept_doit(struct sk_buff *skb, struct genl_info *info)
 	struct handshake_net *hn = handshake_pernet(net);
 	struct handshake_req *req = NULL;
 	struct socket *sock;
-	int class, fd, err;
+	int class, err;
 
 	err = -EOPNOTSUPP;
 	if (!hn)
@@ -106,27 +106,25 @@ int handshake_nl_accept_doit(struct sk_buff *skb, struct genl_info *info)
 
 	err = -EAGAIN;
 	req = handshake_req_next(hn, class);
-	if (!req)
+	if (req) {
-		goto out_status;
+		sock = req->hr_sk->sk_socket;
 
-	sock = req->hr_sk->sk_socket;
+		FD_PREPARE(fdf, O_CLOEXEC, sock->file);
-	fd = get_unused_fd_flags(O_CLOEXEC);
+		if (fdf.err) {
-	if (fd < 0) {
+			err = fdf.err;
-		err = fd;
+			goto out_complete;
-		goto out_complete;
+		}
+
+		get_file(sock->file); /* FD_PREPARE() consumes a reference. */
+		err = req->hr_proto->hp_accept(req, info, fd_prepare_fd(fdf));
+		if (err)
+			goto out_complete; /* Automatic cleanup handles fput */
+
+		trace_handshake_cmd_accept(net, req, req->hr_sk, fd_prepare_fd(fdf));
+		fd_publish(fdf);
+		return 0;
 	}
 
-	err = req->hr_proto->hp_accept(req, info, fd);
-	if (err) {
-		put_unused_fd(fd);
-		goto out_complete;
-	}
-
-	fd_install(fd, get_file(sock->file));
-
-	trace_handshake_cmd_accept(net, req, req->hr_sk, fd);
-	return 0;
-
 out_complete:
 	handshake_complete(req, -EIO, NULL);
 out_status:

net/kcm/kcmsock.c

@@ -1560,24 +1560,16 @@ static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 	}
 	case SIOCKCMCLONE: {
 		struct kcm_clone info;
-		struct file *file;
 
-		info.fd = get_unused_fd_flags(0);
+		FD_PREPARE(fdf, 0, kcm_clone(sock));
-		if (unlikely(info.fd < 0))
+		if (fdf.err)
-			return info.fd;
+			return fdf.err;
 
-		file = kcm_clone(sock);
+		info.fd = fd_prepare_fd(fdf);
-		if (IS_ERR(file)) {
+		if (copy_to_user((void __user *)arg, &info, sizeof(info)))
-			put_unused_fd(info.fd);
-			return PTR_ERR(file);
-		}
-		if (copy_to_user((void __user *)arg, &info,
-				 sizeof(info))) {
-			put_unused_fd(info.fd);
-			fput(file);
 			return -EFAULT;
-		}
+
-		fd_install(info.fd, file);
+		fd_publish(fdf);
 		err = 0;
 		break;
 	}

net/socket.c

@@ -503,21 +503,12 @@ EXPORT_SYMBOL(sock_alloc_file);
 
 static int sock_map_fd(struct socket *sock, int flags)
 {
-	struct file *newfile;
+	int fd;
-	int fd = get_unused_fd_flags(flags);
+
-	if (unlikely(fd < 0)) {
+	fd = FD_ADD(flags, sock_alloc_file(sock, flags, NULL));
+	if (fd < 0)
 		sock_release(sock);
-		return fd;
+	return fd;
-	}
-
-	newfile = sock_alloc_file(sock, flags, NULL);
-	if (!IS_ERR(newfile)) {
-		fd_install(fd, newfile);
-		return fd;
-	}
-
-	put_unused_fd(fd);
-	return PTR_ERR(newfile);
 }
 
 /**
@@ -2012,8 +2003,6 @@ static int __sys_accept4_file(struct file *file, struct sockaddr __user *upeer_s
 			      int __user *upeer_addrlen, int flags)
 {
 	struct proto_accept_arg arg = { };
-	struct file *newfile;
-	int newfd;
 
 	if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
 		return -EINVAL;
@@ -2021,18 +2010,7 @@ static int __sys_accept4_file(struct file *file, struct sockaddr __user *upeer_s
 	if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
 		flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
 
-	newfd = get_unused_fd_flags(flags);
+	return FD_ADD(flags, do_accept(file, &arg, upeer_sockaddr, upeer_addrlen, flags));
-	if (unlikely(newfd < 0))
-		return newfd;
-
-	newfile = do_accept(file, &arg, upeer_sockaddr, upeer_addrlen,
-			    flags);
-	if (IS_ERR(newfile)) {
-		put_unused_fd(newfd);
-		return PTR_ERR(newfile);
-	}
-	fd_install(newfd, newfile);
-	return newfd;
 }
 
 /*

net/unix/af_unix.c

@@ -3276,9 +3276,6 @@ EXPORT_SYMBOL_GPL(unix_outq_len);
 
 static int unix_open_file(struct sock *sk)
 {
-	struct file *f;
-	int fd;
-
 	if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
 		return -EPERM;
 
@@ -3288,18 +3285,7 @@ static int unix_open_file(struct sock *sk)
 	if (!unix_sk(sk)->path.dentry)
 		return -ENOENT;
 
-	fd = get_unused_fd_flags(O_CLOEXEC);
+	return FD_ADD(O_CLOEXEC, dentry_open(&unix_sk(sk)->path, O_PATH, current_cred()));
-	if (fd < 0)
-		return fd;
-
-	f = dentry_open(&unix_sk(sk)->path, O_PATH, current_cred());
-	if (IS_ERR(f)) {
-		put_unused_fd(fd);
-		return PTR_ERR(f);
-	}
-
-	fd_install(fd, f);
-	return fd;
 }
 
 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)