Re: [PATCH] cgroup:be able to remove the record of unplugged device

[Paul Menage]

On Sun, Jul 24, 2011 at 11:03 PM, Wanlong Gao <gaowanlong@xxxxxxxxxxxxxx> wrote:
> @@ -826,15 +826,15 @@ static int blkio_policy_parse_and_set(char *buf,
>
>        dev = MKDEV(major, minor);
>
> +       if (s[1] == NULL)
> +               return -EINVAL;
> +

How can s[1] be NULL? If there aren't two parameters in the input we'd
have returned earlier since i!=2, and each element in s[] is
initialized from a pointer that has been dereference immediately
beforehand, and hence can't be NULL.

>        ret = blkio_check_dev_num(dev);
> -       if (ret)
> +       if (ret && (strcmp(s[1], "0\0")))
>                return ret;

Better to move the parsing of s[1] ahead of this, and do a numerical
comparison? Otherwise this will miss the case where the input string
is e.g. "8:0 00"

Paul
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