linux-kernel - Re: [PATCH v5 3/4] mtd: core: protect access to MTD devices while in suspend

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Message-ID: <20211129094129.xn364czofrgtvfb4@skn-laptop>
Date:   Mon, 29 Nov 2021 10:41:29 +0100
From:   Sean Nyekjaer <sean@...nix.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Cc:     Boris Brezillon <boris.brezillon@...labora.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Boris Brezillon <bbrezillon@...nel.org>,
        linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 3/4] mtd: core: protect access to MTD devices while in
 suspend

On Mon, Nov 29, 2021 at 10:19:08AM +0100, Miquel Raynal wrote:
> Hi Sean,
> 
> boris.brezillon@...labora.com wrote on Tue, 23 Nov 2021 14:07:15 +0100:
> 
> > On Tue, 23 Nov 2021 13:50:12 +0100
> > Sean Nyekjaer <sean@...nix.com> wrote:
> > 
> > > @Boris do we need to do something similar here to what we did with the
> > > mtdconcat stuff?  
> > 
> > Absolutely, physmasp subdevices are never initialized/registered, so
> > you can't call any of the mtd helpers taking the suspend lock on those.
> > I guess it'd be better to call mtd_suspend/resume() on the concat device
> > in though:
> 
> Any chance that you will come up with a fix or v6 of the series anytime
> soon?
> 
> > 
> > static void physmap_flash_shutdown(struct platform_device *dev)
> > {
> > 	struct physmap_flash_info *info = platform_get_drvdata(dev);
> > 
> > 	mtd_suspend(info->cmtd);
> > }
> 
> 
> Thanks,
> Miquèl

Hi Miquèl,

I'm not 100% comfortable in doing this.

During this patch series I have mostly been Boris' tester and
implemented his ideas :/

I'm willing to give it a try, if Marek shares how to reproduce this with qemu :)

/Sean