linux-kernel - Re: [PATCH v3 1/2] ubi: provide a way to skip CRC checks

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Date:   Mon, 02 Jul 2018 09:43:48 +0200
From:   Richard Weinberger <richard@....at>
To:     dedekind1@...il.com
Cc:     Quentin Schulz <quentin.schulz@...tlin.com>, dwmw2@...radead.org,
        computersforpeace@...il.com, boris.brezillon@...tlin.com,
        marek.vasut@...il.com, linux-mtd@...ts.infradead.org,
        linux-kernel@...r.kernel.org, thomas.petazzoni@...tlin.com
Subject: Re: [PATCH v3 1/2] ubi: provide a way to skip CRC checks

Artem,

Am Montag, 2. Juli 2018, 09:30:25 CEST schrieb Artem Bityutskiy:
> Hi,
> 
> On Thu, 2018-06-28 at 09:40 +0200, Quentin Schulz wrote:
> > diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
> > index d4b2e87..e9e9ecb 100644
> > --- a/drivers/mtd/ubi/kapi.c
> > +++ b/drivers/mtd/ubi/kapi.c
> > @@ -202,7 +202,7 @@ struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
> >  	desc->mode = mode;
> >  
> >  	mutex_lock(&ubi->ckvol_mutex);
> > -	if (!vol->checked) {
> > +	if (!vol->checked && !vol->skip_check) {
> >  		/* This is the first open - check the volume */
> >  		err = ubi_check_volume(ubi, vol_id);
> >  		if (err < 0) {
> 
> Did you deliberately did not add a similar check to 'vol_cdev_write()' ?
> You want to skip checking on load but do have the checking after volume update ?
> Looks a bit inconsistent to me. At the very least deserves a comment in
> 'vol_cdev_write()' about why 'skip_check' flag is ignored there.

Well, the idea is skipping the check, not the crc32 on the medium.
That way we can later, if needed, offer a way to drop the flag but
and don't have to rewrite with crc32-enabled.

Thanks,
//richard