[PATCH 6/14] arch/parisc: Eliminate NULL test and memset after alloc_bootmem

[PATCH 6/14] arch/parisc: Eliminate NULL test and memset after alloc_bootmem

[Julia Lawall]

From: Julia Lawall <julia@diku.dk>

As noted by Akinobu Mita in patch b1fceac2b9e04d278316b2faddf276015fc06e3b,
alloc_bootmem and related functions never return NULL and always return a
zeroed region of memory.  Thus a NULL test or memset after calls to these
functions is unnecessary.

 arch/parisc/mm/init.c |    1 -
 1 file changed, 1 deletion(-)

This was fixed using the following semantic patch.
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression E;
statement S;
@@

E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...)
... when != E
(
- BUG_ON (E == NULL);
|
- if (E == NULL) S
)

@@
expression E,E1;
@@

E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...)
... when != E
- memset(E,0,E1);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
---

diff -u -p a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -765,7 +765,6 @@ static void __init pagetable_init(void)
 #endif
 
 	empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
-	memset(empty_zero_page, 0, PAGE_SIZE);
 }
 
 static void __init gateway_init(void)

Re: [PATCH 6/14] arch/parisc: Eliminate NULL test and memset after alloc_bootmem

[Grant Grundler]

On Tue, Jun 24, 2008 at 10:23:28AM +0200, Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
> 
> As noted by Akinobu Mita in patch b1fceac2b9e04d278316b2faddf276015fc06e3b,
> alloc_bootmem and related functions never return NULL and always return a
> zeroed region of memory.  Thus a NULL test or memset after calls to these
> functions is unnecessary.
> 
>  arch/parisc/mm/init.c |    1 -
>  1 file changed, 1 deletion(-)
> 
> This was fixed using the following semantic patch.
> (http://www.emn.fr/x-info/coccinelle/)
> 
> // <smpl>
> @@
> expression E;
> statement S;
> @@
> 
> E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...)
> ... when != E
> (
> - BUG_ON (E == NULL);
> |
> - if (E == NULL) S
> )
> 
> @@
> expression E,E1;
> @@
> 
> E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...)
> ... when != E
> - memset(E,0,E1);
> // </smpl>
> 
> Signed-off-by: Julia Lawall <julia@diku.dk>

Acked-by: Grant Grundler <grundler@parisc-linux.org>

thanks,
grant

> ---
> 
> diff -u -p a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
> --- a/arch/parisc/mm/init.c
> +++ b/arch/parisc/mm/init.c
> @@ -765,7 +765,6 @@ static void __init pagetable_init(void)
>  #endif
>  
>  	empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
> -	memset(empty_zero_page, 0, PAGE_SIZE);
>  }
>  
>  static void __init gateway_init(void)
> --
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