aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorJulia Lawall <julia@diku.dk>2009-01-06 14:39:28 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-06 15:59:02 -0800
commit58a01a45721bf7bd3a41a86248c3cb02a6b0c501 (patch)
tree2f897de228d8879b981797fdb1ee7d46418e453a
parentcbf84b7add8103b92aaa84928e335df726bfc8da (diff)
mm/page_alloc.c: 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/page_alloc.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2f644c3..ce2a026 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3381,10 +3381,8 @@ static void __init setup_usemap(struct pglist_data *pgdat,
{
unsigned long usemapsize = usemap_size(zonesize);
zone->pageblock_flags = NULL;
- if (usemapsize) {
+ if (usemapsize)
zone->pageblock_flags = alloc_bootmem_node(pgdat, usemapsize);
- memset(zone->pageblock_flags, 0, usemapsize);
- }
}
#else
static void inline setup_usemap(struct pglist_data *pgdat,