linux-kernel - Re: [PATCH] mtd: set mtd partition panic write flag

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Message-ID: <CAKekbeucdjZgttQfHeiXH6S92He2qkKGsQcEqz_4_okHzDK16A@mail.gmail.com>
Date:   Thu, 9 Jan 2020 10:25:59 -0500
From:   Kamal Dasu <kamal.dasu@...adcom.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
Cc:     Richard Weinberger <richard@....at>,
        Kamal Dasu <kdasu.kdev@...il.com>,
        linux-mtd <linux-mtd@...ts.infradead.org>,
        bcm-kernel-feedback-list <bcm-kernel-feedback-list@...adcom.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Vignesh Raghavendra <vigneshr@...com>
Subject: Re: [PATCH] mtd: set mtd partition panic write flag

Miquel,

Yes the issue is still open. I was trying to understand the suggestion
and did not get a reply on the question I had

Richard wrote :
"So the right fix would be setting the parent's oops_panic_write in
mtd_panic_write().
Then we don't have to touch mtdpart.c"

How do I get access to the parts parent in the core ?. Maybe I am
missing something.

Kamal

On Thu, Jan 9, 2020 at 10:03 AM Miquel Raynal <miquel.raynal@...tlin.com> wrote:
>
> Hello,
>
> Richard Weinberger <richard@....at> wrote on Wed, 6 Nov 2019 00:03:42
> +0100 (CET):
>
> > ----- Ursprüngliche Mail -----
> > > Von: "Miquel Raynal" <miquel.raynal@...tlin.com>
> > > An: "Kamal Dasu" <kdasu.kdev@...il.com>
> > > CC: "linux-mtd" <linux-mtd@...ts.infradead.org>, "bcm-kernel-feedback-list" <bcm-kernel-feedback-list@...adcom.com>,
> > > "linux-kernel" <linux-kernel@...r.kernel.org>, "David Woodhouse" <dwmw2@...radead.org>, "Brian Norris"
> > > <computersforpeace@...il.com>, "Marek Vasut" <marek.vasut@...il.com>, "richard" <richard@....at>, "Vignesh Raghavendra"
> > > <vigneshr@...com>
> > > Gesendet: Dienstag, 5. November 2019 20:03:44
> > > Betreff: Re: [PATCH] mtd: set mtd partition panic write flag
> >
> > > Hi Kamal,
> > >
> > > Richard, something to look into below :)
> >
> > I'm still recovering from a bad cold. So my brain is not fully working ;)
> >
> > > Kamal Dasu <kdasu.kdev@...il.com> wrote on Mon, 21 Oct 2019 15:32:52
> > > -0400:
> > >
> > >> Check mtd panic write flag and set the mtd partition panic
> > >> write flag so that low level drivers can use it to take
> > >> required action to ensure oops data gets written to assigned
> > >> mtd partition.
> > >
> > > I feel there is something wrong with the current implementation
> > > regarding partitions but I am not sure this is the right fix. Is this
> > > something you detected with some kind of static checker or did you
> > > actually experience an issue?
> > >
> > > In the commit log you say "check mtd (I suppose you mean the
> > > master) panic write flag and set the mtd partition panic write flag"
> > > which makes sense, but in reality my understanding is that you do the
> > > opposite: you check mtd->oops_panic_write which is the partitions'
> > > structure, and set part->parent->oops_panic_write which is the master's
> > > flag.
> >
> > IIUC the problem happens when you run mtdoops on a mtd partition.
> > The the flag is only set for the partition instead for the master.
> >
> > So the right fix would be setting the parent's oops_panic_write in
> > mtd_panic_write().
> > Then we don't have to touch mtdpart.c
> >
>
> This issue is still open, right? Kamal can you send an updated version?
>
>
> Thanks,
> Miquèl