From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH 13/12] memcg: don't need memcg->memcg_name
Date: Mon, 8 Apr 2013 20:59:07 -0700
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To: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Cgroups <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org

On Tue, Apr 09, 2013 at 11:18:21AM +0800, Li Zefan wrote:
> >> -		if (memcg->memcg_name)
> >> -			seq_printf(m, "%s:\n", memcg->memcg_name);
> >> +		ret = cgroup_path(memcg->css.cgroup, memcg_name, PAGE_SIZE);
> >> +		if (!ret)
> >> +			seq_printf(m, "%s:\n", memcg_name);
> >>   		else
> >>   			seq_printf(m, "%p (name lost):\n", memcg);
> >>   
> > 
> > I'm sorry for dawm question ...when this error happens ?
> > We may get ENAMETOOLONG even with PAGE_SIZE(>=4096bytes) buffer ?
> > 
> 
> It does no harm to check the return value, and we don't have to
> worry about if cgroup_path() will be changed to return some other
> errno like ENOMEM in the future.

Maybe change the function to return the length of the path regardless
of the specified buffer length?  ie. as in snprintf()?

-- 
tejun