Re: [PATCH 2/3] c/r: add checkpoint/restore methods to struct proto_ops

[Oren Laadan <orenl-RdfvBDnrOixBDgjK7y7TUQ@public.gmane.org>]

Dan Smith wrote:
> OL> -	if ((h->sock.type != SOCK_DGRAM) && (h->sock.type != SOCK_STREAM)) {
> OL> -		ckpt_debug("Socket type %i not supported", h->sock.type);
> OL> +	if (h->sock.type & ~SOCK_TYPE_MASK)
> OL>  		return ERR_PTR(-EINVAL);
> OL> -	}
> 
> The idea here was to prevent a rewritten checkpoint stream from
> causing us to call sock_create() with a type that we don't support.
> Checking the mask may be functionally equivalent right now, but may
> open the door for an interesting failure later, no?

I figured that if we called a sock_create() for a type that isn't
supported by checkpoint/restart, we will catch it down the code by
testing sock->ops->restore. That way, I don't need to "teach"
sock_file_restore() about socket types and protocols.

> 
> OL>  static const struct proto_ops unix_seqpacket_ops = {
> OL> @@ -565,6 +569,8 @@ static const struct proto_ops unix_seqpacket_ops = {
> OL>  	.recvmsg =	unix_dgram_recvmsg,
> OL>  	.mmap =		sock_no_mmap,
> OL>  	.sendpage =	sock_no_sendpage,
> OL> +	.checkpoint =	sock_unix_checkpoint,
> OL> +	.restore =	sock_unix_restore,
> OL>  };
> 
> Have you tested SEQPACKET?  I haven't.

Hehe ... I guess I'm too eager :)

Do you see any reason why it should work ?  The only difference (for
afunix) between dgram and seqpacket is the requirement that the socket
be connected - see unix_seqpacket_sendmsg().

> 
> Other than that, it looks fine to me and fails the same set of tests
> that the current tree does.
> 

Thanks,

Oren.