2.6.28-rc5: unused variable in pagetable_init

2.6.28-rc5: unused variable in pagetable_init

[Andrey Borzenkov]

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  CC      arch/x86/mm/init_32.o
/home/bor/src/linux-git/arch/x86/mm/init_32.c: In function ‘pagetable_init’:
/home/bor/src/linux-git/arch/x86/mm/init_32.c:515: warning: unused variable ‘pgd_base’

Well, pagetable_init is noop unless HIGHMEM is defined so it could be
as simple as that.

Or is something else expected to go into pagetable_init for more general
case?

--- arch/x86/mm/init_32.c       2008-11-10 06:19:14.000000000 +0300
+++ /tmp/init_32.c      2008-11-17 06:52:21.383685722 +0300
@@ -435,9 +435,17 @@ static void __init set_highmem_pages_ini
 }
 #endif /* !CONFIG_NUMA */

+static void __init pagetable_init(void)
+{
+       pgd_t *pgd_base = swapper_pg_dir;
+
+       permanent_kmaps_init(pgd_base);
+}
+
 #else
 # define permanent_kmaps_init(pgd_base)                do { } while (0)
 # define set_highmem_pages_init()      do { } while (0)
+# define pagetable_init()      do { } while (0)
 #endif /* CONFIG_HIGHMEM */

 void __init native_pagetable_setup_start(pgd_t *base)
@@ -510,13 +518,6 @@ static void __init early_ioremap_page_ta
        early_ioremap_reset();
 }

-static void __init pagetable_init(void)
-{
-       pgd_t *pgd_base = swapper_pg_dir;
-
-       permanent_kmaps_init(pgd_base);
-}
-
 #ifdef CONFIG_ACPI_SLEEP
 /*
  * ACPI suspend needs this for resume, because things like the intel-agp

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Re: 2.6.28-rc5: unused variable in pagetable_init

[Ingo Molnar]

* Andrey Borzenkov <arvidjaar@mail.ru> wrote:

>   CC      arch/x86/mm/init_32.o
> /home/bor/src/linux-git/arch/x86/mm/init_32.c: In function ‘pagetable_init’:
> /home/bor/src/linux-git/arch/x86/mm/init_32.c:515: warning: unused variable ‘pgd_base’
> 
> Well, pagetable_init is noop unless HIGHMEM is defined so it could 
> be as simple as that.
> 
> Or is something else expected to go into pagetable_init for more 
> general case?
> 
> --- arch/x86/mm/init_32.c       2008-11-10 06:19:14.000000000 +0300
> +++ /tmp/init_32.c      2008-11-17 06:52:21.383685722 +0300
> @@ -435,9 +435,17 @@ static void __init set_highmem_pages_ini
>  }
>  #endif /* !CONFIG_NUMA */
> 
> +static void __init pagetable_init(void)
> +{
> +       pgd_t *pgd_base = swapper_pg_dir;
> +
> +       permanent_kmaps_init(pgd_base);
> +}
> +
>  #else
>  # define permanent_kmaps_init(pgd_base)                do { } while (0)
>  # define set_highmem_pages_init()      do { } while (0)
> +# define pagetable_init()      do { } while (0)
>  #endif /* CONFIG_HIGHMEM */
> 
>  void __init native_pagetable_setup_start(pgd_t *base)
> @@ -510,13 +518,6 @@ static void __init early_ioremap_page_ta
>         early_ioremap_reset();
>  }
> 
> -static void __init pagetable_init(void)
> -{
> -       pgd_t *pgd_base = swapper_pg_dir;
> -
> -       permanent_kmaps_init(pgd_base);
> -}
> -
>  #ifdef CONFIG_ACPI_SLEEP

The better fix would be to convert permanent_kmaps_init() from a macro 
to an (empty) inline. That way CPP does not eat away the code and GCC 
will known that the variable is indeed used.

	Ingo