From 67222c4ba8afe409d1e049a8f1e687c8a214fec7 Mon Sep 17 00:00:00 2001
From: Li Lingfeng <lilingfeng3@huawei.com>
Date: Fri, 20 Jan 2023 11:23:52 +0800
Subject: [PATCH] lib: parser: optimize match_NUMBER apis to use local array
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: 2c0647988433 ("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>
---
lib/parser.c | 39 ++++++++++++++++++++-------------------
1 file changed, 20 insertions(+), 19 deletions(-)
diff --git a/lib/parser.c b/lib/parser.c
index bcb23484100ee..2b5e2b480253f 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 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);
--
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