On Tue, Apr 26, 2022 at 11:32:02PM +0530, Jagdish Gediya wrote:
> At many places in kernel, It is necessary to convert sysfs input
> to corrosponding bool value e.g. "false" or "0" need to be converted
> to bool false, "true" or "1" need to be converted to bool true,
> places where such conversion is needed currently check the input
> string manually, kstrtobool() can be utilized at such places but
> currently it doesn't have support to accept "false"/"true".
>
> Add support to accept "false"/"true" as valid string in kstrtobool().
>
> Signed-off-by: Jagdish Gediya <jvgediya@xxxxxxxxxxxxx>
> Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
I've just spotted that this broke arm64's "rodata=full" command line option,
since "full" gets parsed as 'f' = FALSE, when previously that would have been
rejected. So anyone passing "rodata=full" on the command line will have rodata
disabled, which is not what they wanted.
The current state of things is a bit messy (we prase the option twice because
arch code needs it early), and we can probably fix that with some refactoring,
but I do wonder if we actually want to open up the sysfs parsing to accept
anything *beginning* with [tTfF] rather than the full "true" and "false"
strings as previously, or whether it's worth reverting this for now in case
anything else is affected.
Mark.
> ---
> Chnages in v2:
> - kstrtobool to kstrtobool() in commit message.
> - Split single patch into 2
> - Remove strcmp usage from kstrtobool() and instead compare 1st
> character only.
>
> Changes in v3:
> - Covert -> Convert in patch 2 subject
> - Collected Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
>
> lib/kstrtox.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/lib/kstrtox.c b/lib/kstrtox.c
> index 886510d248e5..465e31e4d70d 100644
> --- a/lib/kstrtox.c
> +++ b/lib/kstrtox.c
> @@ -340,7 +340,7 @@ EXPORT_SYMBOL(kstrtos8);
> * @s: input string
> * @res: result
> *
> - * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
> + * This routine returns 0 if the first character is one of 'YyTt1NnFf0', or
> * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value
> * pointed to by res is updated upon finding a match.
> */
> @@ -353,11 +353,15 @@ int kstrtobool(const char *s, bool *res)
> switch (s[0]) {
> case 'y':
> case 'Y':
> + case 't':
> + case 'T':
> case '1':
> *res = true;
> return 0;
> case 'n':
> case 'N':
> + case 'f':
> + case 'F':
> case '0':
> *res = false;
> return 0;
> --
> 2.35.1
>
>
