linux-kernel - Re: [PATCH v4 03/11] mtd: spi-nor: core: Use auto-detection only once

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Message-ID: <20220421131657.d6hm7rltyxcb24wo@ti.com>
Date:   Thu, 21 Apr 2022 18:46:57 +0530
From:   Pratyush Yadav <p.yadav@...com>
To:     <Tudor.Ambarus@...rochip.com>
CC:     <michael@...le.cc>, <miquel.raynal@...tlin.com>, <richard@....at>,
        <vigneshr@...com>, <linux-mtd@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <Takahiro.Kuwano@...ineon.com>
Subject: Re: [PATCH v4 03/11] mtd: spi-nor: core: Use auto-detection only once

On 21/04/22 07:18AM, Tudor.Ambarus@...rochip.com wrote:
> Hi, Pratyush,
> 
> I forgot to remove few checks, would you please remove them when applying?
> See below.
> 
> On 4/20/22 13:34, Tudor Ambarus wrote:
> > In case spi_nor_match_name() returned NULL, the auto detection was
> > issued twice. There's no reason to try to detect the same chip twice,
> > do the auto detection only once.
> > 
> > Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
> > Reviewed-by: Michael Walle <michael@...le.cc>
> > ---
> >  drivers/mtd/spi-nor/core.c | 13 ++++++++-----
> >  1 file changed, 8 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> > index b9cc8bbf1f62..b55d922d46dd 100644
> > --- a/drivers/mtd/spi-nor/core.c
> > +++ b/drivers/mtd/spi-nor/core.c
> > @@ -2896,13 +2896,14 @@ static const struct flash_info *spi_nor_get_flash_info(struct spi_nor *nor,
> >  {
> >  	const struct flash_info *info = NULL;
> >  
> > -	if (name)
> > +	if (name) {
> >  		info = spi_nor_match_name(nor, name);
> > +		if (IS_ERR(info))
> > +			return info;
> 
> As Michael suggested spi_nor_match_name() returns NULL or valid entry, so this
> check is not necessary, let's remove them.
> 
> > +	}
> >  	/* Try to auto-detect if chip name wasn't specified or not found */
> >  	if (!info)
> > -		info = spi_nor_read_id(nor);
> > -	if (IS_ERR_OR_NULL(info))
> > -		return ERR_PTR(-ENOENT);
> > +		return spi_nor_read_id(nor);
> >  
> >  	/*
> >  	 * If caller has specified name of flash model that can normally be
> > @@ -2994,7 +2995,9 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
> >  		return -ENOMEM;
> >  
> >  	info = spi_nor_get_flash_info(nor, name);
> > -	if (IS_ERR(info))
> > +	if (!info)
> > +		return -ENOENT;
> 
> also according to Michael, this change is not needed as spi_nor_get_flash_info() can't
> return NULL. Here we can keep the code as it was. Let me know if you want me to respin.

TBH I don't think a NULL check here hurts much since the behaviour might 
change later, and error paths don't get exercised as often. But I have 
made both changes when applying. You can double-check at [0] if you 
want.

[0] https://github.com/prati0100/linux-0day/commit/67d913746833ee54bf4c661040f3ef13657dffd8

> 
> > +	else if (IS_ERR(info))
> >  		return PTR_ERR(info);
> >  
> >  	nor->info = info;
> 

-- 
Regards,
Pratyush Yadav
Texas Instruments Inc.