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[ARM] eliminate NULL test and memset after alloc_bootmem 

As noted by Akinobu Mita in patch b1fceac2b9,
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@diku.dk>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Julia Lawall 2008-12-01 14:15:41 -08:00 committed by Russell King
parent d517cab1c7
commit 6ce1b871db
1 changed files with 2 additions and 3 deletions
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5
arch/arm/mm/mmu.c
View File

@ -827,7 +827,6 @@ static void __init devicemaps_init(struct machine_desc *mdesc)
* Allocate the vector page early.
*/
vectors = alloc_bootmem_low_pages(PAGE_SIZE);
BUG_ON(!vectors);
for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
pmd_clear(pmd_off_k(addr));
@ -912,10 +911,10 @@ void __init paging_init(struct machine_desc *mdesc)
top_pmd = pmd_off_k(0xffff0000);
/*
* allocate the zero page. Note that we count on this going ok.
* allocate the zero page. Note that this always succeeds and
* returns a zeroed result.
*/
zero_page = alloc_bootmem_low_pages(PAGE_SIZE);
memset(zero_page, 0, PAGE_SIZE);
empty_zero_page = virt_to_page(zero_page);
flush_dcache_page(empty_zero_page);
}