Re: [PATCH-ugly] kmemtrace: casting a gfp_t requires __force

From: Alexey Dobriyan
Date: Fri Nov 07 2008 - 14:17:22 EST


On Fri, Nov 07, 2008 at 10:58:41AM -0800, Harvey Harrison wrote:
> --- a/include/linux/kmemtrace.h
> +++ b/include/linux/kmemtrace.h
> @@ -34,7 +34,7 @@ static inline void kmemtrace_mark_alloc_node(enum kmemtrace_type_id type_id,
> "bytes_req %lu bytes_alloc %lu gfp_flags %lu node %d",
> type_id, call_site, (unsigned long) ptr,
> (unsigned long) bytes_req, (unsigned long) bytes_alloc,
> - (unsigned long) gfp_flags, node);
> + (__force unsigned long)gfp_flags, node);

gfp_t is "unsigned int" actually. These casts are bogus.

Subject: How do I printk <type> correctly?

If variable is of Type use printk format specifier.
---------------------------------------------------------
int %d or %x
unsigned int %u or %x
long %ld ot %lx
unsigned long %lu or %lx
long long %lld or %llx
unsigned long long %llu or %llx
size_t %zu or %zx
ssize_t %zd or %zx

Raw pointer value SHOULD be printed with %p.

u64 SHOULD be printed with %llu/%llx, (unsigned long long):

printk("%llu", (unsigned long long)u64_var);

s64 SHOULD be printed with %lld/%llx, (long long):

printk("%lld", (long long)s64_var);

If type is dependent on config option (sector_t), use format specifier
of biggest type and explicitly cast to it.

Reminder: sizeof() result is of type size_t.

Thank you for your cooperation.

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