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authorAl Viro <viro@www.linux.org.uk>2005-05-01 08:59:19 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-01 08:59:19 -0700
commitf8e08a8466c4ac5f61b4bdb6338fd97eedb9c9e8 (patch)
tree082b472e19d4b21f2ecb0eb486e961b16ffeaab0 /include
parent6b9f5829e6e3af44f20c681e26524c637d4f82ff (diff)
downloadlinux-f8e08a8466c4ac5f61b4bdb6338fd97eedb9c9e8.tar.bz2
[PATCH] reiserfs endianness: sanitize reiserfs_key union
Since we only access reiserfs_key ->u.k_offset_v2 guts in four helper functions, we are free to sanitize those, as long as - layout of the structure is unchanged (it's on-disk object) - behaviour of these helpers is same as before. Patch kills the mess with endianness-dependent bitfields and replaces them with a single __le64. Helpers are switched to straightforward shift/and/or. Benefits: - exact same definitions for little- and big-endian architectures; no ifdefs in sight. - generate the same code on little-endian and improved on big-endian. - doesn't rely on lousy bitfields handling in gcc codegenerator. - happens to be standard C (unsigned long long is not a valid type for a bitfield; it's a gccism and not well-implemented one, at that). Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk> Cc: <reiserfs-dev@namesys.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/reiserfs_fs.h42
1 files changed, 7 insertions, 35 deletions
diff --git a/include/linux/reiserfs_fs.h b/include/linux/reiserfs_fs.h
index d445b682ce00..32148625fc2f 100644
--- a/include/linux/reiserfs_fs.h
+++ b/include/linux/reiserfs_fs.h
@@ -381,57 +381,29 @@ struct offset_v1 {
} __attribute__ ((__packed__));
struct offset_v2 {
-#ifdef __LITTLE_ENDIAN
- /* little endian version */
- __u64 k_offset:60;
- __u64 k_type: 4;
-#else
- /* big endian version */
- __u64 k_type: 4;
- __u64 k_offset:60;
-#endif
+ __le64 v;
} __attribute__ ((__packed__));
-#ifndef __LITTLE_ENDIAN
-typedef union {
- struct offset_v2 offset_v2;
- __u64 linear;
-} __attribute__ ((__packed__)) offset_v2_esafe_overlay;
-
static inline __u16 offset_v2_k_type( const struct offset_v2 *v2 )
{
- offset_v2_esafe_overlay tmp = *(const offset_v2_esafe_overlay *)v2;
- tmp.linear = le64_to_cpu( tmp.linear );
- return (tmp.offset_v2.k_type <= TYPE_MAXTYPE)?tmp.offset_v2.k_type:TYPE_ANY;
+ __u8 type = le64_to_cpu(v2->v) >> 60;
+ return (type <= TYPE_MAXTYPE)?type:TYPE_ANY;
}
static inline void set_offset_v2_k_type( struct offset_v2 *v2, int type )
{
- offset_v2_esafe_overlay *tmp = (offset_v2_esafe_overlay *)v2;
- tmp->linear = le64_to_cpu(tmp->linear);
- tmp->offset_v2.k_type = type;
- tmp->linear = cpu_to_le64(tmp->linear);
+ v2->v = (v2->v & cpu_to_le64(~0ULL>>4)) | cpu_to_le64((__u64)type<<60);
}
static inline loff_t offset_v2_k_offset( const struct offset_v2 *v2 )
{
- offset_v2_esafe_overlay tmp = *(const offset_v2_esafe_overlay *)v2;
- tmp.linear = le64_to_cpu( tmp.linear );
- return tmp.offset_v2.k_offset;
+ return le64_to_cpu(v2->v) & (~0ULL>>4);
}
static inline void set_offset_v2_k_offset( struct offset_v2 *v2, loff_t offset ){
- offset_v2_esafe_overlay *tmp = (offset_v2_esafe_overlay *)v2;
- tmp->linear = le64_to_cpu(tmp->linear);
- tmp->offset_v2.k_offset = offset;
- tmp->linear = cpu_to_le64(tmp->linear);
+ offset &= (~0ULL>>4);
+ v2->v = (v2->v & cpu_to_le64(15ULL<<60)) | cpu_to_le64(offset);
}
-#else
-# define offset_v2_k_type(v2) ((v2)->k_type)
-# define set_offset_v2_k_type(v2,val) (offset_v2_k_type(v2) = (val))
-# define offset_v2_k_offset(v2) ((v2)->k_offset)
-# define set_offset_v2_k_offset(v2,val) (offset_v2_k_offset(v2) = (val))
-#endif
/* Key of an item determines its location in the S+tree, and
is composed of 4 components */