[PATCH 2/14] arch/frv: Eliminate NULL test and memset after alloc_bootmem

[PATCH 2/14] arch/frv: 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/frv/mm/init.c |    2 --
 1 file changed, 2 deletions(-)

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/frv/mm/init.c b/arch/frv/mm/init.c
--- a/arch/frv/mm/init.c
+++ b/arch/frv/mm/init.c
@@ -118,8 +118,6 @@ void __init paging_init(void)
 
 		pkmap_page_table = alloc_bootmem_pages(PAGE_SIZE);
 
-		memset(pkmap_page_table, 0, PAGE_SIZE);
-
 		pge = swapper_pg_dir + pgd_index_k(PKMAP_BASE);
 		pue = pud_offset(pge, PKMAP_BASE);
 		pme = pmd_offset(pue, PKMAP_BASE);

Re: [PATCH 2/14] arch/frv: Eliminate NULL test and memset after alloc_bootmem

[David Howells]

Julia Lawall <julia@diku.dk> wrote:

> 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.

Acked-by: David Howells <dhowells@redhat.com>