diff options
Diffstat (limited to 'kernel/cgroup/cgroup.c')
| -rw-r--r-- | kernel/cgroup/cgroup.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index cdbeff87fa99..aaba2a41562a 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6240,6 +6240,48 @@ 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. @@ -6402,4 +6444,5 @@ static int __init cgroup_sysfs_init(void) return sysfs_create_group(kernel_kobj, &cgroup_sysfs_attr_group); } subsys_initcall(cgroup_sysfs_init); + #endif /* CONFIG_SYSFS */ |