Miao Xie
2010-Mar-25 12:28 UTC
[PATCH 02/18] btrfs: Calculate member variant''s address directly for btrfs_##name
From: Zhao Lei <zhaolei@cn.fujitsu.com>
It can decrease a additional address calculation and increase little speed.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
fs/btrfs/struct-funcs.c | 10 +++++-----
1 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c
index c0f7eca..b0f80c0 100644
--- a/fs/btrfs/struct-funcs.c
+++ b/fs/btrfs/struct-funcs.c
@@ -49,13 +49,13 @@ u##bits btrfs_##name(struct extent_buffer *eb, \
{ \
unsigned long part_offset = (unsigned long)s; \
unsigned long offset = part_offset + offsetof(type, member); \
- type *p; \
+ u##bits *p; \
/* ugly, but we want the fast path here */ \
if (eb->map_token && offset >= eb->map_start && \
offset + sizeof(((type *)0)->member) <= eb->map_start + \
eb->map_len) { \
- p = (type *)(eb->kaddr + part_offset - eb->map_start); \
- return le##bits##_to_cpu(p->member); \
+ p = (u##bits *)(eb->kaddr + offset - eb->map_start); \
+ return le##bits##_to_cpu(*p); \
} \
{ \
int err; \
@@ -74,8 +74,8 @@ u##bits btrfs_##name(struct extent_buffer *eb, \
read_eb_member(eb, s, type, member, &leres); \
return le##bits##_to_cpu(leres); \
} \
- p = (type *)(kaddr + part_offset - map_start); \
- res = le##bits##_to_cpu(p->member); \
+ p = (u##bits *)(kaddr + offset - map_start); \
+ res = le##bits##_to_cpu(*p); \
if (unmap_on_exit) \
unmap_extent_buffer(eb, map_token, KM_USER1); \
return res; \
--
1.6.5.2
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