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Subject[PATCH 5/14] arch/m68k/mm/Sun3mmu.c: Eliminate NULL test and memset after alloc_bootmem
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/m68k/mm/sun3mmu.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/m68k/mm/sun3mmu.c b/arch/m68k/mm/sun3mmu.c
--- a/arch/m68k/mm/sun3mmu.c
+++ b/arch/m68k/mm/sun3mmu.c
@@ -53,7 +53,6 @@ void __init paging_init(void)
wp_works_ok = 0;
#endif
empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
- memset(empty_zero_page, 0, PAGE_SIZE);

address = PAGE_OFFSET;
pg_dir = swapper_pg_dir;

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