Re: [PATCH v2 1/4] lib/string_helpers: export string_units_{2,10} for others

From: James Bottomley
Date: Sat Jan 23 2016 - 00:13:34 EST


On Thu, 2016-01-21 at 17:22 +0200, Andy Shevchenko wrote:
> There is one user coming which would like to use those string arrays.
> It might
> be useful for any other user in the future.

Well, let's not do it until we have an actual consumer because that
will help us get the interface correct.

> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
> include/linux/string_helpers.h | 6 ++++++
> lib/string_helpers.c | 21 ++++++++++++---------
> 2 files changed, 18 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/string_helpers.h
> b/include/linux/string_helpers.h
> index dabe643..a55c9cc 100644
> --- a/include/linux/string_helpers.h
> +++ b/include/linux/string_helpers.h
> @@ -10,6 +10,12 @@ enum string_size_units {
> STRING_UNITS_2, /* use binary powers of 2^10
> */
> };
>
> +#define STRING_UNITS_10_NUM 9
> +#define STRING_UNITS_2_NUM 9
> +
> +extern const char *const string_units_10[STRING_UNITS_10_NUM];
> +extern const char *const string_units_2[STRING_UNITS_2_NUM];
> +
> void string_get_size(u64 size, u64 blk_size, enum string_size_units
> units,
> char *buf, int len);
>
> diff --git a/lib/string_helpers.c b/lib/string_helpers.c
> index 5939f63..7ee4644 100644
> --- a/lib/string_helpers.c
> +++ b/lib/string_helpers.c
> @@ -13,6 +13,15 @@
> #include <linux/string.h>
> #include <linux/string_helpers.h>
>
> +const char * const string_units_10[STRING_UNITS_10_NUM] = {
> + "B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB",
> +};
> +EXPORT_SYMBOL(string_units_10);
> +const char * const string_units_2[STRING_UNITS_2_NUM] = {
> + "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB",
> +};
> +EXPORT_SYMBOL(string_units_2);
> +

This is a pretty silly thing to do; how does someone who adds a unit to
one of the string_units know to increment STRING_UNITS_X_NUM? Even if
you add a comment admonishing them to do it, it's far better to have
this calculated at compile time like it was before this patch.

James