cgroup: Move cgroup_parse_float() implementation out of CONFIG_SYSFS

mainline inclusion
from mainline-5.3-rc1
commit 38cf3a687f5827fcfc81cbc433ef5822693a49c1
category: feature
bugzilla: 38688
CVE: NA

---------------------------

a5e112e6424a ("cgroup: add cgroup_parse_float()") accidentally added
cgroup_parse_float() inside CONFIG_SYSFS block.  Move it outside so
that it doesn't cause failures on !CONFIG_SYSFS builds.
Signed-off-by: NTejun Heo <tj@kernel.org>
Fixes: a5e112e6424a ("cgroup: add cgroup_parse_float()")
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

kernel/cgroup/cgroup.c

@@ -5899,6 +5899,48 @@ struct cgroup *cgroup_get_from_fd(int fd)
 }
 EXPORT_SYMBOL_GPL(cgroup_get_from_fd);
 
+static u64 power_of_ten(int power)
+{
+	u64 v = 1;
+	while (power--)
+		v *= 10;
+	return v;
+}
+
+/**
+ * cgroup_parse_float - parse a floating number
+ * @input: input string
+ * @dec_shift: number of decimal digits to shift
+ * @v: output
+ *
+ * Parse a decimal floating point number in @input and store the result in
+ * @v with decimal point right shifted @dec_shift times.  For example, if
+ * @input is "12.3456" and @dec_shift is 3, *@v will be set to 12345.
+ * Returns 0 on success, -errno otherwise.
+ *
+ * There's nothing cgroup specific about this function except that it's
+ * currently the only user.
+ */
+int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v)
+{
+	s64 whole, frac = 0;
+	int fstart = 0, fend = 0, flen;
+
+	if (!sscanf(input, "%lld.%n%lld%n", &whole, &fstart, &frac, &fend))
+		return -EINVAL;
+	if (frac < 0)
+		return -EINVAL;
+
+	flen = fend > fstart ? fend - fstart : 0;
+	if (flen < dec_shift)
+		frac *= power_of_ten(dec_shift - flen);
+	else
+		frac = DIV_ROUND_CLOSEST_ULL(frac, power_of_ten(flen - dec_shift));
+
+	*v = whole * power_of_ten(dec_shift) + frac;
+	return 0;
+}
+
 /*
  * sock->sk_cgrp_data handling.  For more info, see sock_cgroup_data
  * definition in cgroup-defs.h.
@@ -6077,46 +6119,4 @@ static int __init cgroup_sysfs_init(void)
 }
 subsys_initcall(cgroup_sysfs_init);
 
-static u64 power_of_ten(int power)
-{
-	u64 v = 1;
-	while (power--)
-		v *= 10;
-	return v;
-}
-
-/**
- * cgroup_parse_float - parse a floating number
- * @input: input string
- * @dec_shift: number of decimal digits to shift
- * @v: output
- *
- * Parse a decimal floating point number in @input and store the result in
- * @v with decimal point right shifted @dec_shift times.  For example, if
- * @input is "12.3456" and @dec_shift is 3, *@v will be set to 12345.
- * Returns 0 on success, -errno otherwise.
- *
- * There's nothing cgroup specific about this function except that it's
- * currently the only user.
- */
-int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v)
-{
-	s64 whole, frac = 0;
-	int fstart = 0, fend = 0, flen;
-
-	if (!sscanf(input, "%lld.%n%lld%n", &whole, &fstart, &frac, &fend))
-		return -EINVAL;
-	if (frac < 0)
-		return -EINVAL;
-
-	flen = fend > fstart ? fend - fstart : 0;
-	if (flen < dec_shift)
-		frac *= power_of_ten(dec_shift - flen);
-	else
-		frac = DIV_ROUND_CLOSEST_ULL(frac, power_of_ten(flen - dec_shift));
-
-	*v = whole * power_of_ten(dec_shift) + frac;
-	return 0;
-}
-
 #endif /* CONFIG_SYSFS */