New bcache compiler warning (was: Re: bcache: Minor fixes from kbuild robot)

From: Geert Uytterhoeven
Date: Mon Feb 17 2014 - 16:00:32 EST


On Fri, Feb 14, 2014 at 8:04 PM, Linux Kernel Mailing List
<linux-kernel@xxxxxxxxxxxxxxx> wrote:
> bcache: Minor fixes from kbuild robot

> diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c
> index 4f6b594..3f74b4b 100644
> --- a/drivers/md/bcache/bset.c
> +++ b/drivers/md/bcache/bset.c
> @@ -23,7 +23,7 @@ void bch_dump_bset(struct btree_keys *b, struct bset *i, unsigned set)
> for (k = i->start; k < bset_bkey_last(i); k = next) {
> next = bkey_next(k);
>
> - printk(KERN_ERR "block %u key %zi/%u: ", set,
> + printk(KERN_ERR "block %u key %li/%u: ", set,
> (uint64_t *) k - i->d, i->keys);
>
> if (b->ops->key_dump)

On 32-bit (m68k):
drivers/md/bcache/bset.c: In function âbch_dump_bsetâ:
drivers/md/bcache/bset.c:27: warning: format â%liâ expects type âlong
intâ, but argument 3 has type âintâ

What are you trying to print here? It looks a bit strange to me.
Technically, the difference between two pointers is of type ptrdiff_.
The kernel had

typedef __kernel_ptrdiff_t ptrdiff_t;

and

#if __BITS_PER_LONG != 64
typedef unsigned int __kernel_size_t;
typedef int __kernel_ssize_t;
typedef int __kernel_ptrdiff_t;
#else
typedef __kernel_ulong_t __kernel_size_t;
typedef __kernel_long_t __kernel_ssize_t;
typedef __kernel_long_t __kernel_ptrdiff_t;
#endif

So I'd expect "%zi" to be the right way, and a quick test compile on
32-bit (m68k)
and 64-bit (amd64) comfirms that. What was wrong with it?

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/