From 6ce1b871db6a3ca69ed1e35956d89d3cacd7ba08 Mon Sep 17 00:00:00 2001 From: Julia Lawall Date: Mon, 1 Dec 2008 14:15:41 -0800 Subject: [PATCH] [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/) // @@ 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); // Signed-off-by: Julia Lawall Cc: Russell King Signed-off-by: Andrew Morton Signed-off-by: Russell King --- arch/arm/mm/mmu.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 2ab5f962a05..9b36c5cb5e9 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); } -- 2.41.0