Messages in this thread | | | Date | Sat, 8 Nov 2008 00:50:16 +0200 | From | Eduard - Gabriel Munteanu <> | Subject | Re: [PATCH-ugly] kmemtrace: casting a gfp_t requires __force |
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On Fri, Nov 07, 2008 at 10:20:29PM +0300, Alexey Dobriyan wrote: > 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.
Hi,
Actually, "%zu" was the first thing that crossed my mind too. But we don't want to carry such types into the probe callbacks. It's a lot easier to see which u* an unsigned long fits into than it is for size_t. So we take care of this inside a wrapper; the sooner, the better.
Also take into account that debugging code usually casts pointers to unsigned long. This can easily be seen by looking at _RET_IP_ definition or SLAB code. I think there's a very good reason to do so, since it adds opacity to something that's not supposed to be used as a pointer.
Cheers, Eduard
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