Messages in this thread Patch in this message | | | Date | Tue, 24 Jun 2008 10:25:17 +0200 (CEST) | From | Julia Lawall <> | Subject | [PATCH 10/14] arch/um: Eliminate NULL test and memset after alloc_bootmem |
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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/um/drivers/net_kern.c | 4 ---- arch/um/kernel/initrd.c | 2 -- arch/um/kernel/physmem.c | 3 --- 3 files changed, 9 deletions(-)
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/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c --- a/arch/um/drivers/net_kern.c +++ b/arch/um/drivers/net_kern.c @@ -668,10 +668,6 @@ static int __init eth_setup(char *str) } new = alloc_bootmem(sizeof(*new)); - if (new == NULL) { - printk(KERN_ERR "eth_init : alloc_bootmem failed\n"); - return 1; - } INIT_LIST_HEAD(&new->list); new->index = n; diff -u -p a/arch/um/kernel/initrd.c b/arch/um/kernel/initrd.c --- a/arch/um/kernel/initrd.c +++ b/arch/um/kernel/initrd.c @@ -37,8 +37,6 @@ static int __init read_initrd(void) } area = alloc_bootmem(size); - if (area == NULL) - return 0; if (load_initrd(initrd, area, size) == -1) return 0; diff -u -p a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c --- a/arch/um/kernel/physmem.c +++ b/arch/um/kernel/physmem.c @@ -41,12 +41,9 @@ int __init init_maps(unsigned long physm total_len = phys_len + iomem_len + highmem_len; map = alloc_bootmem_low_pages(total_len); - if (map == NULL) - return -ENOMEM; for (i = 0; i < total_pages; i++) { p = &map[i]; - memset(p, 0, sizeof(struct page)); SetPageReserved(p); INIT_LIST_HEAD(&p->lru); }
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