Messages in this thread Patch in this message | | | From | Li Lingfeng <> | Subject | [PATCH-next RESEND v2] lib: parser: optimize match_NUMER apis to use local array | Date | Wed, 11 Jan 2023 12:22:15 +0800 |
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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> Acked-by: Tejun Heo <tj@kernel.org> --- lib/parser.c | 42 +++++++++++++++++++++++------------------- 1 file changed, 23 insertions(+), 19 deletions(-)
diff --git a/lib/parser.c b/lib/parser.c 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); -- 2.31.1
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