From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Morton <akpm@linux-foundation.org>
Date: Thu, 21 Jan 2016 21:45:05 -0800
Subject: [Ocfs2-devel] [PATCH 2/6] ocfs2: o2hb: add NEGO_TIMEOUT message
In-Reply-To: <56A1BA3A.20700@oracle.com>
References: <1453259619-5347-1-git-send-email-junxiao.bi@oracle.com>
	<1453259619-5347-3-git-send-email-junxiao.bi@oracle.com>
	<20160121154707.569ce8d12cce6cf43bc5e31c@linux-foundation.org>
	<56A1BA3A.20700@oracle.com>
Message-ID: <20160121214505.2a177efa.akpm@linux-foundation.org>
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To: ocfs2-devel@oss.oracle.com

On Fri, 22 Jan 2016 13:12:26 +0800 Junxiao Bi <junxiao.bi@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@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.