From: Richard Weinberger <richard@nod.at>
To: hch <hch@lst.de>
Cc: joern <joern@lazybastard.org>,
Miquel Raynal <miquel.raynal@bootlin.com>,
Vignesh Raghavendra <vigneshr@ti.com>,
linux-mtd <linux-mtd@lists.infradead.org>
Subject: Re: [PATCH] mtd/block2mtd: don't poke into block layer internals
Date: Fri, 22 Oct 2021 09:50:29 +0200 (CEST) [thread overview]
Message-ID: <977960225.24313.1634889029764.JavaMail.zimbra@nod.at> (raw)
In-Reply-To: <20211019055309.GA20805@lst.de>
----- Ursprüngliche Mail -----
> Von: "hch" <hch@lst.de>
> An: "richard" <richard@nod.at>
> CC: "hch" <hch@lst.de>, "joern" <joern@lazybastard.org>, "Miquel Raynal" <miquel.raynal@bootlin.com>, "Vignesh
> Raghavendra" <vigneshr@ti.com>, "linux-mtd" <linux-mtd@lists.infradead.org>
> Gesendet: Dienstag, 19. Oktober 2021 07:53:09
> Betreff: Re: [PATCH] mtd/block2mtd: don't poke into block layer internals
> On Thu, Oct 14, 2021 at 09:28:19PM +0200, Richard Weinberger wrote:
>> > instead. Note that this contains a small behavior change in that erase
>> > now unconditionally writes all Fs instead of first scanning for them.
>>
>> Unless you have a strong opinoin I'd like to keep the scanning.
>> The original use case of block2mtd is using Compact Flash (ATA)
>> as MTD. Some of this devices are super stupid and I fear the 0xFF scanning
>> is here to avoid programming 0xFF bytes into the NAND.
>> Just to be on the safe side...
>
> I played with keeping the scanning, but it really is a mess. Shouldn't
> the higher layers (ubi, jffs2, etc) know what has already been erased?
Well, the higher layers are allowed to unconditionally re-erase a block.
I had a short discussion with Miquel, since it is not entirely clear what
the purpose of the read-before-write logic in the erase handler is, let's
keep on the safe side and keep it.
Either it is a performance optimization because erase was super slow on
compact flash cards at the time when Joern created block2mtd.
Or they have been super stupid^Wsimple and writing 0xFF bytes to an erased
region (via mtd_erase) was problematic.
> Btw, Joerns address bounces. Does anyone know if he still wants to
> maintain block2mtd and has a new address or if he should be removed from
> the maintainers list?
I sent a patch to remove him from the maintainers file.
If Joern returns I'll happily revert the patch.
Thanks,
//richard
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prev parent reply other threads:[~2021-10-22 7:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-14 14:52 RFC: decouple block2mtd from block layer internals Christoph Hellwig
2021-10-14 14:52 ` [PATCH] mtd/block2mtd: don't poke into " Christoph Hellwig
2021-10-14 19:28 ` Richard Weinberger
2021-10-15 6:28 ` hch
2021-10-15 6:53 ` Miquel Raynal
2021-10-19 5:53 ` hch
2021-10-22 7:50 ` Richard Weinberger [this message]
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