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| author | Chris Mason <chris.mason@oracle.com> | 2007-10-15 16:14:37 -0400 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2008-09-25 11:03:56 -0400 |
| commit | 6d36dcd48f1e4e7446d603a3df9638bd314a182d (patch) | |
| tree | 321f6f36de71adaab1754b113401e05d50cd5ebd /fs/btrfs/ctree.h | |
| parent | 479965d66e320f1a095bb76027171daa675a9c72 (diff) | |
| download | linux-6d36dcd48f1e4e7446d603a3df9638bd314a182d.tar.gz | |
Btrfs: Avoid memcpy where possible in extent_buffers
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/ctree.h')
| -rw-r--r-- | fs/btrfs/ctree.h | 45 |
1 files changed, 40 insertions, 5 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 30fbbd7221a9..aed08618aca6 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -483,15 +483,50 @@ static inline void btrfs_set_##name(struct extent_buffer *eb, \ #define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits) \ static inline u##bits btrfs_##name(struct extent_buffer *eb) \ { \ - __le##bits res; \ - read_eb_member(eb, NULL, type, member, &res); \ - return le##bits##_to_cpu(res); \ + int err; \ + char *map_token; \ + char *kaddr; \ + unsigned long map_start; \ + unsigned long map_len; \ + unsigned long offset = offsetof(type, member); \ + err = map_extent_buffer(eb, offset, \ + sizeof(((type *)0)->member), \ + &map_token, &kaddr, \ + &map_start, &map_len, KM_USER0); \ + if (!err) { \ + __le##bits *tmp = (__le##bits *)(kaddr + offset - \ + map_start); \ + u##bits res = le##bits##_to_cpu(*tmp); \ + unmap_extent_buffer(eb, map_token, KM_USER0); \ + return res; \ + } else { \ + __le##bits res; \ + read_eb_member(eb, NULL, type, member, &res); \ + return le##bits##_to_cpu(res); \ + } \ } \ static inline void btrfs_set_##name(struct extent_buffer *eb, \ u##bits val) \ { \ - val = cpu_to_le##bits(val); \ - write_eb_member(eb, NULL, type, member, &val); \ + int err; \ + char *map_token; \ + char *kaddr; \ + unsigned long map_start; \ + unsigned long map_len; \ + unsigned long offset = offsetof(type, member); \ + err = map_extent_buffer(eb, offset, \ + sizeof(((type *)0)->member), \ + &map_token, &kaddr, \ + &map_start, &map_len, KM_USER0); \ + if (!err) { \ + __le##bits *tmp = (__le##bits *)(kaddr + offset - \ + map_start); \ + *tmp = cpu_to_le##bits(val); \ + unmap_extent_buffer(eb, map_token, KM_USER0); \ + } else { \ + val = cpu_to_le##bits(val); \ + write_eb_member(eb, NULL, type, member, &val); \ + } \ } #define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits) \ |