From: Joakim Tjernlund <Joakim.Tjernlund@infinera.com>
To: "nkela@cisco.com" <nkela@cisco.com>,
"dwmw2@infradead.org" <dwmw2@infradead.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
"xe-linux-external@cisco.com" <xe-linux-external@cisco.com>
Subject: Re: [PATCH] jffs2: implement mount option to configure endianness
Date: Wed, 7 Nov 2018 09:16:39 +0000 [thread overview]
Message-ID: <1e4c066d1896e2a0b8b146253d34d05cc4f9ab36.camel@infinera.com> (raw)
In-Reply-To: <921b0f78cf67d7307a0555e1fd6f2c2976310adc.camel@infradead.org>
On Wed, 2018-11-07 at 10:05 +0100, David Woodhouse wrote:
>
> On Tue, 2018-11-06 at 13:49 -0800, Nikunj Kela wrote:
> > This patch allows the endianness of the JFSS2 filesystem to be
> > specified by mount option 'force_endian=big|little|native'. If
> > endianness is not specified, it defaults to 'native' endianness
> > thus retaining the existing behavior.
> >
> > Some architectures benefit from having a single known endianness
> > of JFFS2 filesystem (for data, not executables) independent of the
> > endianness of the processor (ARM processors can be switched to either
> > endianness at run-time).
> >
> > We have boards that are shipped with BE jffs2 and BE kernel. We are
> > now migrating to LE kernel. This mount option helps us in mounting
> > BE jffs2 on LE kernel.
>
> Thanks for implementing this. JFFS2 has often been very sensitive to
> performance at mount time — I'd love to see how this affects the time
> taken to mount a large file system. If it's significant, we may want a
> config option to make this conditional?
Yes, this may slow things down. I am not sure I agree with the impl. either.
Could one not make cpu_to_je_X/jeX_to_cpu a function ptr which is set to
a func. with the correct endian?
That way it should also be easy to have a config option for endian: Native/BE/LE or Dynamic
Jocke
next prev parent reply other threads:[~2018-11-07 9:16 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-06 21:49 [PATCH] jffs2: implement mount option to configure endianness Nikunj Kela
2018-11-07 9:05 ` David Woodhouse
2018-11-07 9:16 ` Joakim Tjernlund [this message]
2018-11-07 16:12 ` David Woodhouse
2018-11-07 17:33 ` Daniel Walker
2018-11-07 17:58 ` David Woodhouse
2018-11-07 18:41 ` Joakim Tjernlund
2018-11-08 15:25 ` Christoph Hellwig
2018-11-07 19:21 ` Daniel Walker
2018-11-07 18:04 ` Nikunj Kela (nkela)
2018-11-07 18:14 ` Richard Weinberger
2018-11-08 8:11 ` David Woodhouse
2018-11-08 18:01 ` Nikunj Kela (nkela)
2018-11-08 18:50 ` Joakim Tjernlund
2018-11-08 19:47 ` David Woodhouse
2018-11-12 21:43 ` Daniel Walker
2018-11-12 22:50 ` Daniel Walker
2018-11-12 23:11 ` David Woodhouse
2018-11-12 23:40 ` Daniel Walker
2018-11-12 23:43 ` David Woodhouse
2018-11-13 0:06 ` Daniel Walker
2018-11-13 21:01 ` Daniel Walker
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