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SubjectRe: [PATCH] vmalloc: remove #ifdef in function body
On Tue, Dec 20, 2011 at 09:31:21PM -0800, Joe Perches wrote:
> On Wed, 2011-12-21 at 14:17 +0900, Minchan Kim wrote:
> > We don't like function body which include #ifdef.
> []
> > diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> []
> > @@ -505,6 +505,7 @@ static void unmap_vmap_area(struct vmap_area *va)
> > vunmap_page_range(va->va_start, va->va_end);
> > }
> >
> > +#ifdef CONFIG_DEBUG_PAGEALLOC
> > static void vmap_debug_free_range(unsigned long start, unsigned long end)
> > {
> > /*
> > @@ -520,11 +521,15 @@ static void vmap_debug_free_range(unsigned long start, unsigned long end)
> > * debugging doesn't do a broadcast TLB flush so it is a lot
> > * faster).
> > */
> > -#ifdef CONFIG_DEBUG_PAGEALLOC
> > vunmap_page_range(start, end);
> > flush_tlb_kernel_range(start, end);
> > -#endif
> > }
> > +#else
> > +static inline void vmap_debug_free_range(unsigned long start,
> > + unsigned long end)
> > +{
> > +}
> > +#endif
>
> I don't like this change.
> I think it's perfectly good style to use:

I feel it's no problem as it is because it's very short function now
but it's not style we prefer.

>
> 1 void foo(args...)
> 2 {
> 3 #ifdef CONFIG_FOO
> 4 ...
> 5 #endif
> 6 }
>
> instead of
>
> 1 #ifdef CONFIG_FOO
> 2 void foo(args...)
> 3 {
> 4 ...
> 5 }
> 6 #else
> 7 void foo(args...)
> 8 {
> 9 }
> 10 #endif
>
> The first version is shorter and gcc optimizes
> away the void func just fine. It also means

Agree but if function would be long(but I convice
it's not long in future :)), it would be messy.

> that 2 function prototypes don't need to be
> kept in agreement when someone changes one
> without testing CONFIG_FOO=y and CONFIG_FOO=n.

The goal is not for making test easily.
Patch author should keep it consistent.

This patch is just trivial so I don't mind if who have
against this patch strongly. What I want to say is
it's not style we prefer.

>
>

--
Kind regards,
Minchan Kim


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