Re: [PATCH v2] ubi: gluebi: Fix NULL pointer dereference caused by ftl notifier

From: Richard Weinberger <richard@nod.at>
To: chengzhihao1 <chengzhihao1@huawei.com>
Cc: ZhaoLong Wang <wangzhaolong1@huawei.com>,
	 Miquel Raynal <miquel.raynal@bootlin.com>,
	 Vignesh Raghavendra <vigneshr@ti.com>,
	 dpervushin <dpervushin@embeddedalley.com>,
	 Artem Bityutskiy <Artem.Bityutskiy@nokia.com>,
	 linux-mtd <linux-mtd@lists.infradead.org>,
	 linux-kernel <linux-kernel@vger.kernel.org>,
	 yi zhang <yi.zhang@huawei.com>, yangerkun <yangerkun@huawei.com>
Subject: Re: [PATCH v2] ubi: gluebi: Fix NULL pointer dereference caused by ftl notifier
Date: Mon, 23 Oct 2023 09:15:41 +0200 (CEST)	[thread overview]
Message-ID: <879960555.29268.1698045341596.JavaMail.zimbra@nod.at> (raw)
In-Reply-To: <93b2d5ab-e36c-be08-7343-ef4ca16f991d@huawei.com>

----- Ursprüngliche Mail -----
> Von: "chengzhihao1" <chengzhihao1@huawei.com>
>>> If we add new ioctls to control creation/destroying of gluebi, then
>>> gluebi mtd won't be automatically created when UBI volume is added. I'm
>>> not certain whether this change will effect existing startup process
>>> that depends on gluebi.
>> 
>> Let's take a stack back. The sole purpose of gluebi is providing
>> a way to run JFFS2 on top of UBI.
> 
> Is it possible that someone runs ext4 on mtdblock based on gluebi, for
> the advantage of wear-leveling?

Unless they want to kill their NAND immediately, no.
UBIblock hat initially an RW-Mode but it was rejected because
UBI is not an FTL and will all dangerous setups.

What I'm trying to say is, I'd like to avoid adding complicated solutions
or workarounds just to make artificial stacking of outdated MTD components
possible.
Let's keep the big picture in mind.

Thanks,
//richard

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