linux-kernel - Re: State of the UBI fastmap feature

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAFLxGvxdqkvhZmMnL+KzTW4O-cL1oJ+WL6koD1TzBnVzJ7oLjA@mail.gmail.com>
Date: Tue, 2 Sep 2025 09:48:15 +0200
From: Richard Weinberger <richard.weinberger@...il.com>
To: Richard Weinberger <richard.weinberger@...il.com>, linux-mtd@...ts.infradead.org, 
	linux-kernel@...r.kernel.org
Subject: Re: State of the UBI fastmap feature

On Tue, Sep 2, 2025 at 9:37 AM Alexander Dahl <ada@...rsis.com> wrote:
> > I guess your motivation is reducing the attach time?
>
> Indeed.  Need to reduce boot time here, and UBI is attached twice.
> Once in U-Boot to read the kernel image and then again in Linux.

Some ideas that could significantly improve attach time while being
less invasive than Fastmap:
1. Pass the LEB-PEB mapping from U-Boot to Linux so that scanning
occurs only in U-Boot.
2. Optimize EC/VID header reads:
2.1. If supported by the device, transfer only the actual header size
instead of the entire (sub)page.
2.2. Read headers without ECC (if ECC overhead is measurable). If the
header CRC fails, re-read with ECC.

-- 
Thanks,
//richard