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SubjectRe: [PATCH-next v2] lib: parser: optimize match_NUMER apis to use local array
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在 2022/12/13 22:17, Li Lingfeng 写道:
> 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.
>
> Using local array to store substring_t to remove the restriction.
>
> Link: https://lore.kernel.org/all/20221104023938.2346986-5-yukuai1@huaweicloud.com/
> Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
> ---
> v1->v2:
> change the name of buffer's length
> use match_strlcpy() to copy string and keep string length check
> lib/parser.c | 42 +++++++++++++++++++++++-------------------
> 1 file changed, 23 insertions(+), 19 deletions(-)
>
> diff --git a/lib/parser.c b/lib/parser.c

I can't find the maintainer of this module through the script, does
anyone know?

[lilingfeng@ceph-admin linux-next]$ ./scripts/get_maintainer.pl
0001-lib-parser-optimize-match_NUMER-apis-to-use-local-ar.patch

Bad divisor in main::vcs_assign: 0
"GitAuthor: Li Lingfeng" <lilingfeng3@huawei.com>
(authored:1/1=100%,added_lines:23/23=100%,removed_lines:19/19=100%)
linux-kernel@vger.kernel.org (open list)

Thanks.

> index bcb23484100e..0d00f0adb063 100644
> --- a/lib/parser.c
> +++ b/lib/parser.c
> @@ -11,6 +11,15 @@
> #include <linux/slab.h>
> #include <linux/string.h>
>
> +/*
> + * max size needed by diffrent bases to express U64
> + * HEX: "0xFFFFFFFFFFFFFFFF" --> 18
> + * DEC: "18446744073709551615" --> 20
> + * OCT: "01777777777777777777777" --> 23
> + * pick the max one to define NUMBER_BUF_LEN
> + */
> +#define NUMBER_BUF_LEN 24
> +
> /**
> * match_one - Determines if a string matches a simple pattern
> * @s: the string to examine for presence of the pattern
> @@ -129,14 +138,13 @@ EXPORT_SYMBOL(match_token);
> static int match_number(substring_t *s, int *result, int base)
> {
> char *endp;
> - char *buf;
> + char buf[NUMBER_BUF_LEN];
> int ret;
> long 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);
> ret = 0;
> val = simple_strtol(buf, &endp, base);
> if (endp == buf)
> @@ -145,7 +153,6 @@ static int match_number(substring_t *s, int *result, int base)
> ret = -ERANGE;
> else
> *result = (int) val;
> - kfree(buf);
> return ret;
> }
>
> @@ -163,18 +170,16 @@ 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);
> ret = kstrtoull(buf, base, &val);
> if (!ret)
> *result = val;
> - kfree(buf);
> return ret;
> }
>
> @@ -206,14 +211,13 @@ EXPORT_SYMBOL(match_int);
> */
> int match_uint(substring_t *s, unsigned int *result)
> {
> - int err = -ENOMEM;
> - char *buf = match_strdup(s);
> + char buf[NUMBER_BUF_LEN];
>
> - if (buf) {
> - err = kstrtouint(buf, 10, result);
> - kfree(buf);
> - }
> - return err;
> + if ((s->to - s->from) >= NUMBER_BUF_LEN)
> + return -ERANGE;
> + match_strlcpy(buf, s, NUMBER_BUF_LEN);
> +
> + return kstrtouint(buf, 10, result);
> }
> EXPORT_SYMBOL(match_uint);
>

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