linux-kernel - Re: [PATCH] mtd: spi-nor: Simplify loop in spi_nor_read

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Date:   Wed, 19 Feb 2020 08:06:08 +0000
From:   <Tudor.Ambarus@...rochip.com>
To:     <j.neuschaefer@....net>
CC:     <linux-mtd@...ts.infradead.org>, <miquel.raynal@...tlin.com>,
        <richard@....at>, <vigneshr@...com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mtd: spi-nor: Simplify loop in spi_nor_read_id()

Hi, Jonathan,

On Tuesday, February 18, 2020 5:10:34 PM EET Jonathan Neuschäfer wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> content is safe
> 
> - Don't use `tmp` for two purposes (return value, loop counter)
> - Name the loop counter `i`, as is convention
> - Return the pointer variable that the if conditions leading up to the
>   return statement already operate on, rather than a different
>   expression that evaluates to the same pointer
> 
> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@....net>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index 4fc632ec18fe..c491572d5267 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -2711,7 +2711,7 @@ static const struct flash_info spi_nor_ids[] = {
> 
>  static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
>  {
> -       int                     tmp;
> +       int                     tmp, i;

while cleaning this function, would you rename tmp with ret?

>         u8                      *id = nor->bouncebuf;

and please drop this tab between u8 and *id

>         const struct flash_info *info;

Also, IMO, the definition of variables should be done with the focus of 
avoiding stack padding. With this in mind, I would first define the pointers 
and then the ints and smaller types. But there are others than prefer defining 
the variables in a tree/reverse-tree way, depending of the length of the line. 
There's no agreement on this, either way if fine, do as you prefer.

> 
> @@ -2732,11 +2732,11 @@ static const struct flash_info
> *spi_nor_read_id(struct spi_nor *nor) return ERR_PTR(tmp);
>         }
> 
> -       for (tmp = 0; tmp < ARRAY_SIZE(spi_nor_ids) - 1; tmp++) {
> -               info = &spi_nor_ids[tmp];
> +       for (i = 0; i < ARRAY_SIZE(spi_nor_ids) - 1; i++) {
> +               info = &spi_nor_ids[i];
>                 if (info->id_len) {
>                         if (!memcmp(info->id, id, info->id_len))
> -                               return &spi_nor_ids[tmp];
> +                               return info;

Looks good,

Cheers,
ta