linux-kernel - Re: [PATCH-next v3] lib: parser: optimize match

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Date:   Thu, 19 Jan 2023 18:07:27 -0800
From:   Eric Biggers <ebiggers@...nel.org>
To:     Li Lingfeng <lilingfeng3@...wei.com>
Cc:     linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
        tj@...nel.org, axboe@...nel.dk, akpm@...ux-foundation.org,
        jack@...e.cz, bingjingc@...ology.com, james.smart@...adcom.com,
        houtao1@...wei.com, yi.zhang@...wei.com, yangerkun@...wei.com,
        yukuai3@...wei.com
Subject: Re: [PATCH-next v3] lib: parser: optimize match_NUMER apis to use
 local array

On Fri, Jan 20, 2023 at 10:13:04AM +0800, Li Lingfeng wrote:
> [PATCH-next v3] lib: parser: optimize match_NUMER apis to use

NUMER => NUMBER

> Memory will be allocated to store substring_t in match_strdup(), which means
> the caller of match_strdup() may need to be scheduled out to wait for reclaiming
> memory.

Text in commit messages should be wrapped at 72 columns.

> @@ -163,18 +169,16 @@ static int match_number(substring_t *s, int *result, int base)
>   */
>  static int match_u64int(substring_t *s, u64 *result, int base)
>  {
> -	char *buf;
> +	char buf[NUMBER_BUF_LEN];
>  	int ret;
>  	u64 val;
>  
> -	buf = match_strdup(s);
> -	if (!buf)
> -		return -ENOMEM;
> -
> +	if ((s->to - s->from) >= NUMBER_BUF_LEN)
> +		return -ERANGE;
> +	match_strlcpy(buf, s, NUMBER_BUF_LEN);

As I requested on v2, the return value of match_strlcpy() should be used instead
of checking '((s->to - s->from) >= NUMBER_BUF_LEN'.

- Eric