Skip to content

Commit

Permalink
Btrfs: rewrite BTRFS_SETGET_FUNCS
Browse files Browse the repository at this point in the history 
BTRFS_SETGET_FUNCS macro is used to generate btrfs_set_foo() and
btrfs_foo() functions, which read and write specific fields in the
extent buffer.

The total number of set/get functions is ~200, but in fact we only
need 8 functions: 2 for u8 field, 2 for u16, 2 for u32 and 2 for u64.

It results in redunction of ~37K bytes.

   text    data     bss     dec     hex filename
 629661   12489     216  642366   9cd3e fs/btrfs/btrfs.o.orig
 592637   12489     216  605342   93c9e fs/btrfs/btrfs.o

Signed-off-by: Li Zefan <lizefan@huawei.com>
  • Loading branch information
Li Zefan authored and Chris Mason committed Jul 23, 2012
1 parent 293f7e0 commit 18077bb
Show file tree
Hide file tree
Showing 2 changed files with 146 additions and 103 deletions.
53 changes: 47 additions & 6 deletions fs/btrfs/ctree.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1623,13 +1623,54 @@ static inline void btrfs_init_map_token (struct btrfs_map_token *token)
offsetof(type, member), \
sizeof(((type *)0)->member)))

#ifndef BTRFS_SETGET_FUNCS
#define DECLARE_BTRFS_SETGET_BITS(bits) \
u##bits btrfs_get_token_##bits(struct extent_buffer *eb, void *ptr, \
unsigned long off, \
struct btrfs_map_token *token); \
void btrfs_set_token_##bits(struct extent_buffer *eb, void *ptr, \
unsigned long off, u##bits val, \
struct btrfs_map_token *token); \
static inline u##bits btrfs_get_##bits(struct extent_buffer *eb, void *ptr, \
unsigned long off) \
{ \
return btrfs_get_token_##bits(eb, ptr, off, NULL); \
} \
static inline void btrfs_set_##bits(struct extent_buffer *eb, void *ptr, \
unsigned long off, u##bits val) \
{ \
btrfs_set_token_##bits(eb, ptr, off, val, NULL); \
}

DECLARE_BTRFS_SETGET_BITS(8)
DECLARE_BTRFS_SETGET_BITS(16)
DECLARE_BTRFS_SETGET_BITS(32)
DECLARE_BTRFS_SETGET_BITS(64)

#define BTRFS_SETGET_FUNCS(name, type, member, bits) \
u##bits btrfs_##name(struct extent_buffer *eb, type *s); \
u##bits btrfs_token_##name(struct extent_buffer *eb, type *s, struct btrfs_map_token *token); \
void btrfs_set_token_##name(struct extent_buffer *eb, type *s, u##bits val, struct btrfs_map_token *token);\
void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val);
#endif
static inline u##bits btrfs_##name(struct extent_buffer *eb, type *s) \
{ \
BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member); \
return btrfs_get_##bits(eb, s, offsetof(type, member)); \
} \
static inline void btrfs_set_##name(struct extent_buffer *eb, type *s, \
u##bits val) \
{ \
BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member); \
btrfs_set_##bits(eb, s, offsetof(type, member), val); \
} \
static inline u##bits btrfs_token_##name(struct extent_buffer *eb, type *s, \
struct btrfs_map_token *token) \
{ \
BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member); \
return btrfs_get_token_##bits(eb, s, offsetof(type, member), token); \
} \
static inline void btrfs_set_token_##name(struct extent_buffer *eb, \
type *s, u##bits val, \
struct btrfs_map_token *token) \
{ \
BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member); \
btrfs_set_token_##bits(eb, s, offsetof(type, member), val, token); \
}

#define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits) \
static inline u##bits btrfs_##name(struct extent_buffer *eb) \
Expand Down
196 changes: 99 additions & 97 deletions fs/btrfs/struct-funcs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,119 +17,121 @@
*/

#include <linux/highmem.h>
#include <asm/unaligned.h>

/* this is some deeply nasty code. ctree.h has a different
* definition for this BTRFS_SETGET_FUNCS macro, behind a #ifndef
#include "ctree.h"

static inline u8 get_unaligned_le8(const void *p)
{
return *(u8 *)p;
}

static inline void put_unaligned_le8(u8 val, void *p)
{
*(u8 *)p = val;
}

/*
* this is some deeply nasty code.
*
* The end result is that anyone who #includes ctree.h gets a
* declaration for the btrfs_set_foo functions and btrfs_foo functions
*
* This file declares the macros and then #includes ctree.h, which results
* in cpp creating the function here based on the template below.
* declaration for the btrfs_set_foo functions and btrfs_foo functions,
* which are wappers of btrfs_set_token_#bits functions and
* btrfs_get_token_#bits functions, which are defined in this file.
*
* These setget functions do all the extent_buffer related mapping
* required to efficiently read and write specific fields in the extent
* buffers. Every pointer to metadata items in btrfs is really just
* an unsigned long offset into the extent buffer which has been
* cast to a specific type. This gives us all the gcc type checking.
*
* The extent buffer api is used to do all the kmapping and page
* spanning work required to get extent buffers in highmem and have
* a metadata blocksize different from the page size.
*
* The macro starts with a simple function prototype declaration so that
* sparse won't complain about it being static.
* The extent buffer api is used to do the page spanning work required to
* have a metadata blocksize different from the page size.
*/

#define BTRFS_SETGET_FUNCS(name, type, member, bits) \
u##bits btrfs_##name(struct extent_buffer *eb, type *s); \
void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val); \
void btrfs_set_token_##name(struct extent_buffer *eb, type *s, u##bits val, struct btrfs_map_token *token); \
u##bits btrfs_token_##name(struct extent_buffer *eb, \
type *s, struct btrfs_map_token *token) \
#define DEFINE_BTRFS_SETGET_BITS(bits) \
u##bits btrfs_get_token_##bits(struct extent_buffer *eb, void *ptr, \
unsigned long off, \
struct btrfs_map_token *token) \
{ \
unsigned long part_offset = (unsigned long)s; \
unsigned long offset = part_offset + offsetof(type, member); \
type *p; \
int err; \
char *kaddr; \
unsigned long map_start; \
unsigned long map_len; \
unsigned long mem_len = sizeof(((type *)0)->member); \
u##bits res; \
if (token && token->kaddr && token->offset <= offset && \
token->eb == eb && \
(token->offset + PAGE_CACHE_SIZE >= offset + mem_len)) { \
kaddr = token->kaddr; \
p = (type *)(kaddr + part_offset - token->offset); \
res = le##bits##_to_cpu(p->member); \
return res; \
} \
err = map_private_extent_buffer(eb, offset, \
mem_len, \
&kaddr, &map_start, &map_len); \
if (err) { \
__le##bits leres; \
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); \
if (token) { \
token->kaddr = kaddr; \
token->offset = map_start; \
token->eb = eb; \
} \
return res; \
unsigned long part_offset = (unsigned long)ptr; \
unsigned long offset = part_offset + off; \
void *p; \
int err; \
char *kaddr; \
unsigned long map_start; \
unsigned long map_len; \
int size = sizeof(u##bits); \
u##bits res; \
\
if (token && token->kaddr && token->offset <= offset && \
token->eb == eb && \
(token->offset + PAGE_CACHE_SIZE >= offset + size)) { \
kaddr = token->kaddr; \
p = kaddr + part_offset - token->offset; \
res = get_unaligned_le##bits(p + off); \
return res; \
} \
err = map_private_extent_buffer(eb, offset, size, \
&kaddr, &map_start, &map_len); \
if (err) { \
__le##bits leres; \
\
read_extent_buffer(eb, &leres, offset, size); \
return le##bits##_to_cpu(leres); \
} \
p = kaddr + part_offset - map_start; \
res = get_unaligned_le##bits(p + off); \
if (token) { \
token->kaddr = kaddr; \
token->offset = map_start; \
token->eb = eb; \
} \
return res; \
} \
void btrfs_set_token_##name(struct extent_buffer *eb, \
type *s, u##bits val, struct btrfs_map_token *token) \
void btrfs_set_token_##bits(struct extent_buffer *eb, \
void *ptr, unsigned long off, u##bits val, \
struct btrfs_map_token *token) \
{ \
unsigned long part_offset = (unsigned long)s; \
unsigned long offset = part_offset + offsetof(type, member); \
type *p; \
int err; \
char *kaddr; \
unsigned long map_start; \
unsigned long map_len; \
unsigned long mem_len = sizeof(((type *)0)->member); \
if (token && token->kaddr && token->offset <= offset && \
token->eb == eb && \
(token->offset + PAGE_CACHE_SIZE >= offset + mem_len)) { \
kaddr = token->kaddr; \
p = (type *)(kaddr + part_offset - token->offset); \
p->member = cpu_to_le##bits(val); \
return; \
} \
err = map_private_extent_buffer(eb, offset, \
mem_len, \
&kaddr, &map_start, &map_len); \
if (err) { \
__le##bits val2; \
val2 = cpu_to_le##bits(val); \
write_eb_member(eb, s, type, member, &val2); \
return; \
} \
p = (type *)(kaddr + part_offset - map_start); \
p->member = cpu_to_le##bits(val); \
if (token) { \
token->kaddr = kaddr; \
token->offset = map_start; \
token->eb = eb; \
} \
} \
void btrfs_set_##name(struct extent_buffer *eb, \
type *s, u##bits val) \
{ \
btrfs_set_token_##name(eb, s, val, NULL); \
} \
u##bits btrfs_##name(struct extent_buffer *eb, \
type *s) \
{ \
return btrfs_token_##name(eb, s, NULL); \
} \
unsigned long part_offset = (unsigned long)ptr; \
unsigned long offset = part_offset + off; \
void *p; \
int err; \
char *kaddr; \
unsigned long map_start; \
unsigned long map_len; \
int size = sizeof(u##bits); \
\
if (token && token->kaddr && token->offset <= offset && \
token->eb == eb && \
(token->offset + PAGE_CACHE_SIZE >= offset + size)) { \
kaddr = token->kaddr; \
p = kaddr + part_offset - token->offset; \
put_unaligned_le##bits(val, p + off); \
return; \
} \
err = map_private_extent_buffer(eb, offset, size, \
&kaddr, &map_start, &map_len); \
if (err) { \
__le##bits val2; \
\
val2 = cpu_to_le##bits(val); \
write_extent_buffer(eb, &val2, offset, size); \
return; \
} \
p = kaddr + part_offset - map_start; \
put_unaligned_le##bits(val, p + off); \
if (token) { \
token->kaddr = kaddr; \
token->offset = map_start; \
token->eb = eb; \
} \
}

#include "ctree.h"
DEFINE_BTRFS_SETGET_BITS(8)
DEFINE_BTRFS_SETGET_BITS(16)
DEFINE_BTRFS_SETGET_BITS(32)
DEFINE_BTRFS_SETGET_BITS(64)

void btrfs_node_key(struct extent_buffer *eb,
struct btrfs_disk_key *disk_key, int nr)
Expand Down

0 comments on commit 18077bb

Please sign in to comment.