[Ocfs2-devel] [PATCH 2/6] ocfs2: o2hb: add NEGO_TIMEOUT message

[Andrew Morton]

On Fri, 22 Jan 2016 13:12:26 +0800 Junxiao Bi <junxiao.bi at oracle.com> wrote:

> On 01/22/2016 07:47 AM, Andrew Morton wrote:
> > On Wed, 20 Jan 2016 11:13:35 +0800 Junxiao Bi <junxiao.bi at oracle.com> wrote:
> > 
> >> This message is sent to master node when non-master nodes's
> >> negotiate timer expired. Master node records these nodes in
> >> a bitmap which is used to do write timeout timer re-queue
> >> decision.
> >>
> >> ...
> >>
> >> +static int o2hb_nego_timeout_handler(struct o2net_msg *msg, u32 len, void *data,
> >> +				void **ret_data)
> >> +{
> >> +	struct o2hb_region *reg = (struct o2hb_region *)data;
> > 
> > It's best not to typecast a void*.  It's unneeded clutter and the cast
> > can actually hide bugs - if someone changes `data' to a different type
> > or if there's a different "data" in scope, etc.
> There are many kinds of messages in ocfs2 and each one needs a different
> type of "data", so it is made type void*.

What I mean is to do this:

	struct o2hb_region *reg = data;

and not

	struct o2hb_region *reg = (struct o2hb_region *)data;

Because the typecast is unneeded and is actually harmful.  Imagine if someone
goofed and had `int data;': no warning, runtime failure.