[PATCH 2/5] arch/avr32: Eliminate NULL test and memset afteralloc_bootmem

From: Julia Lawall
Date: Sun Nov 23 2008 - 05:47:20 EST


From: Julia Lawall <julia@xxxxxxx>

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.

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

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

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

@@
expression E,E1;
@@

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

Signed-off-by: Julia Lawall <julia@xxxxxxx>
---

arch/avr32/mm/init.c | 1 -
1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/arch/avr32/mm/init.c b/arch/avr32/mm/init.c
index fa92ff6..e819fa6 100644
--- a/arch/avr32/mm/init.c
+++ b/arch/avr32/mm/init.c
@@ -97,7 +97,6 @@ void __init paging_init(void)

mem_map = NODE_DATA(0)->node_mem_map;

- memset(zero_page, 0, PAGE_SIZE);
empty_zero_page = virt_to_page(zero_page);
flush_dcache_page(empty_zero_page);
}
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