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lib: parser: optimize match_NUMBER apis to use local array

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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.  smatch complains that this can cuase sleeping in
an atoic context.

Using local array to store substring_t to remove the restriction.

Link: https://lkml.kernel.org/r/20230120032352.242767-1-lilingfeng3@huawei.com
Link: https://lore.kernel.org/all/20221104023938.2346986-5-yukuai1@huaweicloud.com/
Link: https://lkml.kernel.org/r/20230120032352.242767-1-lilingfeng3@huawei.com
Fixes: 2c06479884 ("blk-iocost: don't release 'ioc->lock' while updating params")
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Reported-by: Yu Kuai <yukuai1@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: BingJing Chang <bingjingc@synology.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Hou Tao <houtao1@huawei.com>
Cc: James Smart <james.smart@broadcom.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: yangerkun <yangerkun@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Li Lingfeng 2023-01-20 11:23:52 +08:00 committed by Andrew Morton
parent badc28d492
commit 67222c4ba8
1 changed files with 20 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
lib/parser.c
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@ -11,6 +11,15 @@
#include <linux/slab.h>
#include <linux/string.h>
/*
* max size needed by different 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 +138,12 @@ 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 (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN)
return -ERANGE;
ret = 0;
val = simple_strtol(buf, &endp, base);
if (endp == buf)
@ -145,7 +152,6 @@ static int match_number(substring_t *s, int *result, int base)
ret = -ERANGE;
else
*result = (int) val;
kfree(buf);
return ret;
}
@ -163,18 +169,15 @@ 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 (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN)
return -ERANGE;
ret = kstrtoull(buf, base, &val);
if (!ret)
*result = val;
kfree(buf);
return ret;
}
@ -206,14 +209,12 @@ 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 (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN)
return -ERANGE;
return kstrtouint(buf, 10, result);
}
EXPORT_SYMBOL(match_uint);