Re: [PATCH 4/4] UBI: Implement bitrot checking (linux-mtd Digest, Vol 145, Issue 24)

From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: Richard Weinberger <richard@nod.at>
Cc: Andrea Scian <rnd4@dave-tech.it>,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
	dedekind1@gmail.com
Subject: Re: [PATCH 4/4] UBI: Implement bitrot checking (linux-mtd Digest, Vol 145, Issue 24)
Date: Sun, 12 Apr 2015 23:30:19 +0200	[thread overview]
Message-ID: <20150412233019.2b4eac3e@bbrezillon> (raw)
In-Reply-To: <552ADD27.6080703@nod.at>

On Sun, 12 Apr 2015 23:01:27 +0200
Richard Weinberger <richard@nod.at> wrote:

> >>>>>> +static struct device_attribute dev_trigger_bitrot_check =
> >>>>>> +    __ATTR(trigger_bitrot_check, S_IWUSR, NULL, trigger_bitrot_check);
> >>>>>
> >>>>> How about making this attribute a RW one, so that users could check
> >>>>> if there's a bitrot check in progress.
> >>>>
> >>>> As the check will be initiated only by userspace and writing to the trigger
> >>>> while a check is running will return anyway a EBUSY I don't really see
> >>>> a point why userspace would check for it.
> >>>
> >>> Sometime you just want to know whether something is running or not (in
> >>> this case the bitrot check) without risking to trigger a new action...
> >>
> >> Why would they care?
> > 
> > I think is always useful to give some additional information in userspace, from both debugging and diagnostic point of view.
> 
> The question is, why does userspace care?
> Other UBI operations are also not visible...

Yes, but AFAIK other wear-leveling operations are not directly triggered
by user-space.

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com