Re: [PATCH 2/3] xen: modify xenstore watch event interface

From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Juergen Gross <jgross@suse.com>,
	linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org
Cc: konrad.wilk@oracle.com, roger.pau@citrix.com,
	wei.liu2@citrix.com, paul.durrant@citrix.com,
	netdev@vger.kernel.org
Subject: Re: [PATCH 2/3] xen: modify xenstore watch event interface
Date: Fri, 6 Jan 2017 16:57:31 -0500	[thread overview]
Message-ID: <c4a181ac-ca47-16bd-5b3d-ea25e413355f@oracle.com> (raw)
In-Reply-To: <20170106150544.10836-3-jgross@suse.com>

On 01/06/2017 10:05 AM, Juergen Gross wrote:
> Today a Xenstore watch event is delivered via a callback function
> declared as:
>
> void (*callback)(struct xenbus_watch *,
>                  const char **vec, unsigned int len);
>
> As all watch events only ever come with two parameters (path and token)
> changing the prototype to:
>
> void (*callback)(struct xenbus_watch *,
>                  const char *path, const char *token);
>
> is the natural thing to do.
>
> Apply this change and adapt all users.
>
> Cc: konrad.wilk@oracle.com
> Cc: roger.pau@citrix.com
> Cc: wei.liu2@citrix.com
> Cc: paul.durrant@citrix.com
> Cc: netdev@vger.kernel.org
>
> Signed-off-by: Juergen Gross <jgross@suse.com>

>  
> @@ -903,24 +902,24 @@ static int process_msg(void)
>  	body[msg->hdr.len] = '\0';
>  
>  	if (msg->hdr.type == XS_WATCH_EVENT) {
> -		msg->u.watch.vec = split(body, msg->hdr.len,
> -					 &msg->u.watch.vec_size);
> -		if (IS_ERR(msg->u.watch.vec)) {
> -			err = PTR_ERR(msg->u.watch.vec);
> +		if (count_strings(body, msg->hdr.len) != 2) {
> +			err = -EINVAL;

xenbus_write_watch() returns -EILSEQ when this type of error is
encountered so perhaps for we should return the same error here.

Either way

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>