Re: [PATCH v2 1/2] fs/fcntl: f_setown, allow returning error

[Jeff Layton <jlayton@redhat.com>]

On Tue, 2017-06-13 at 11:22 +0200, Jiri Slaby wrote:
> Allow f_setown to return an error value. We will fail in the next patch
> with EINVAL for bad input to f_setown, so tile the path for the later
> patch.
> 
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Cc: Jeff Layton <jlayton@poochiereds.net>
> Cc: "J. Bruce Fields" <bfields@fieldses.org>
> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> Cc: linux-fsdevel@vger.kernel.org
> ---
>  fs/fcntl.c         | 7 ++++---
>  include/linux/fs.h | 2 +-
>  net/socket.c       | 3 +--
>  3 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/fcntl.c b/fs/fcntl.c
> index bbf80344c125..313eba860346 100644
> --- a/fs/fcntl.c
> +++ b/fs/fcntl.c
> @@ -109,7 +109,7 @@ void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
>  }
>  EXPORT_SYMBOL(__f_setown);
>  
> -void f_setown(struct file *filp, unsigned long arg, int force)
> +int f_setown(struct file *filp, unsigned long arg, int force)
>  {
>  	enum pid_type type;
>  	struct pid *pid;
> @@ -123,6 +123,8 @@ void f_setown(struct file *filp, unsigned long arg, int force)
>  	pid = find_vpid(who);
>  	__f_setown(filp, pid, type, force);
>  	rcu_read_unlock();
> +
> +	return 0;
>  }
>  EXPORT_SYMBOL(f_setown);
>  
> @@ -305,8 +307,7 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
>  		force_successful_syscall_return();
>  		break;
>  	case F_SETOWN:
> -		f_setown(filp, arg, 1);
> -		err = 0;
> +		err = f_setown(filp, arg, 1);
>  		break;
>  	case F_GETOWN_EX:
>  		err = f_getown_ex(filp, arg);
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index ecc301043abf..6dd215a339d4 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1250,7 +1250,7 @@ extern void fasync_free(struct fasync_struct *);
>  extern void kill_fasync(struct fasync_struct **, int, int);
>  
>  extern void __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
> -extern void f_setown(struct file *filp, unsigned long arg, int force);
> +extern int f_setown(struct file *filp, unsigned long arg, int force);
>  extern void f_delown(struct file *filp);
>  extern pid_t f_getown(struct file *filp);
>  extern int send_sigurg(struct fown_struct *fown);
> diff --git a/net/socket.c b/net/socket.c
> index 8f9dab330d57..59e902b9df09 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -991,8 +991,7 @@ static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg)
>  			err = -EFAULT;
>  			if (get_user(pid, (int __user *)argp))
>  				break;
> -			f_setown(sock->file, pid, 1);
> -			err = 0;
> +			err = f_setown(sock->file, pid, 1);
>  			break;
>  		case FIOGETOWN:
>  		case SIOCGPGRP:

Looks good:

Reviewed-by: Jeff Layton <jlayton@redhat.com>