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From: Richard Weinberger <richard@nod.at>
To: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
	Artem Bityutskiy <dedekind1@gmail.com>,
	Alexander Kaplan <alex@nextthing.co>,
	Brian Norris <computersforpeace@gmail.com>,
	Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Subject: Re: [RFC] Raising the UBI version
Date: Wed, 22 Jun 2016 15:54:34 +0200	[thread overview]
Message-ID: <576A989A.6080502@nod.at> (raw)
In-Reply-To: <20160622144344.07ba4d41@bbrezillon>

Am 22.06.2016 um 14:43 schrieb Boris Brezillon:
> Why do we need to hardcode /sys/class/ubi/version to 1? We just need to
> update the mtd-utils to support version 2. Am I missing something?

We don't want to break existing userspace.
Why should ubimkvol or ubiattach fail on a system with SLC NAND and
CONFIG_MTD_UBI_CONSOLIDATE=y?

Especially since existing tools *will* work with CONFIG_MTD_UBI_CONSOLIDATE=y.
Rasing /sys/class/ubi/version and breaking existing tools is only acceptable
when we change all UBI ioctl() and sysfs files in a way such that version 1
userspace cannot work. Which is not the case here.

This is a nice example why version numbers is bad and feature flags should be used.
Currently UBI mixes the implementation version and the on-flash version.
We're changing only the on-flash version. The user visible ABI stays and will only
get extended.

Thanks,
//richard

  parent reply	other threads:[~2016-06-22 13:55 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-21 19:19 [RFC] Raising the UBI version Richard Weinberger
2016-06-22 12:43 ` Boris Brezillon
2016-06-22 13:09   ` Michal Suchanek
2016-06-22 13:17     ` Boris Brezillon
2016-06-22 13:24       ` Boris Brezillon
2016-06-22 13:54   ` Richard Weinberger [this message]
2016-06-22 14:01     ` Boris Brezillon
2016-06-22 14:05       ` Richard Weinberger
2016-06-22 14:13         ` Boris Brezillon
2016-06-22 14:21           ` Richard Weinberger
2016-06-22 14:39             ` Boris Brezillon
2016-06-22 14:43               ` Richard Weinberger
2016-06-22 14:52                 ` Boris Brezillon
2016-06-22 14:59                   ` Richard Weinberger
2016-06-22 15:06                     ` Boris Brezillon
2016-06-22 19:59                       ` Richard Weinberger
2016-06-22 20:12                         ` Boris Brezillon
2016-06-22 20:24                           ` Richard Weinberger

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