[ARM] eliminate NULL test and memset after alloc_bootmem
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@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>
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 2ab5f96..9b36c5c 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -827,7 +827,6 @@
* 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 @@
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);
}