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authorJulia Lawall <julia@diku.dk>2008-12-01 14:15:41 -0800
committerRussell King <rmk+kernel@arm.linux.org.uk>2008-12-14 12:05:03 +0000
commit6ce1b871db6a3ca69ed1e35956d89d3cacd7ba08 (patch)
treefa3a1d73cc601de707ec21dad485319d42f7bfb5
parentd517cab1c7fc92178e11c7ded2548b06b273d293 (diff)
[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>
-rw-r--r--arch/arm/mm/mmu.c5
1 files changed, 2 insertions, 3 deletions
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 @@ 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);
}