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| author | Julia Lawall <julia@diku.dk> | 2009-01-06 14:39:28 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-06 15:59:02 -0800 |
| commit | 58a01a45721bf7bd3a41a86248c3cb02a6b0c501 (patch) | |
| tree | 2f897de228d8879b981797fdb1ee7d46418e453a | |
| parent | cbf84b7add8103b92aaa84928e335df726bfc8da (diff) | |
| download | linux-3.10-58a01a45721bf7bd3a41a86248c3cb02a6b0c501.tar.gz linux-3.10-58a01a45721bf7bd3a41a86248c3cb02a6b0c501.tar.bz2 linux-3.10-58a01a45721bf7bd3a41a86248c3cb02a6b0c501.zip | |
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.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2f644c3e3da..ce2a026219b 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, |