On Tuesday 04 June 2013, Rob Herring wrote:
> On Sat, Jun 1, 2013 at 3:57 PM, Arnd Bergmann <a...@arndb.de> wrote:
> > On Saturday 01 June 2013, Rob Herring wrote:
> >> No, we still need empty functions. Here is what of_device.h looks like:
> >>
> >> http://tinyurl.com/l2azz5m
> >>
> >> BTW, it has your ack.
> >>
> >
> > Could you add a patch on top that only puts the function declarations
> > inside of #ifdef that don't have an inline wrapper?
>
> I'm confused. You mean that DO have an inline? Like this:
>
> void foo(void);
>
> #ifdef CONFIG_OF
> void bar(void);
> #else
> static inline void bar(void) {}
> #endif
Yes, sorry. That's what I meant.
> > It's really annoying to have to change the header file every time one
> > needs to call a function from a driver in the DT-only case.
>
> The functions without inlines are ones that drivers should not call
> and should only be called from OF enabled code. That's why we have not
> done a complete pass of adding inlines for everything.
The problem is that it's a bad default. The convention in kernel code
is not to hide declarations in #ifdef, for multiple reasons:
* It avoids unnecessary code rebuilds when the symbol changes between
two 'make' runs.
* It lets drivers and platform code call the function from dead code
without causing a build error, thus improving compile coverage.
* It's much nicer to read when can write your code like
void __init exynos_init_io(struct map_desc *mach_desc, int size)
{
if (IS_ENABLED_(CONFIG_OF) && initial_boot_params)
of_scan_flat_dt(exynos_fdt_map_chipid, NULL);
else
iotable_init(exynos_iodesc, ARRAY_SIZE(exynos_iodesc));
...
}
instead of
void __init exynos_init_io(struct map_desc *mach_desc, int size)
{
#ifdef CONFIG_OF
if (initial_boot_params)
of_scan_flat_dt(exynos_fdt_map_chipid, NULL);
else
#endif
iotable_init(exynos_iodesc, ARRAY_SIZE(exynos_iodesc));
...
}
The first one looks like actual C code, the second is really ugly,
and an inline wrapper wouldn't even do the right thing here.
Arnd
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