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btrfs: define separate btrfs_set/get_XX helpers

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There are helpers for all type widths defined via macro and optionally
can use a token which is a cached pointer to avoid repeated mapping of
the extent buffer.

The token value is known at compile time, when it's valid it's always
address of a local variable, otherwise it's NULL passed by the
token-less helpers.

This can be utilized to remove some branching as the helpers are used
frequenlty.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2019-08-09 17:12:38 +02:00
parent 6ff49c6ad2
commit cb49511328
2 changed files with 55 additions and 11 deletions
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15
fs/btrfs/ctree.h
View File

@ -1335,17 +1335,10 @@ u##bits btrfs_get_token_##bits(const struct extent_buffer *eb, \
void btrfs_set_token_##bits(struct extent_buffer *eb, const void *ptr, \
unsigned long off, u##bits val, \
struct btrfs_map_token *token); \
static inline u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
const 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); \
}
u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
const void *ptr, unsigned long off); \
void btrfs_set_##bits(struct extent_buffer *eb, void *ptr, \
unsigned long off, u##bits val);
DECLARE_BTRFS_SETGET_BITS(8)
DECLARE_BTRFS_SETGET_BITS(16)

51
fs/btrfs/struct-funcs.c
View File

@ -33,6 +33,8 @@ static inline void put_unaligned_le8(u8 val, void *p)
*
* The extent buffer api is used to do the page spanning work required to
* have a metadata blocksize different from the page size.
*
* There are 2 variants defined, one with a token pointer and one without.
*/
#define DEFINE_BTRFS_SETGET_BITS(bits) \
@ -75,6 +77,31 @@ u##bits btrfs_get_token_##bits(const struct extent_buffer *eb, \
} \
return res; \
} \
u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
const void *ptr, unsigned long off) \
{ \
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; \
\
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); \
return res; \
} \
void btrfs_set_token_##bits(struct extent_buffer *eb, \
const void *ptr, unsigned long off, \
u##bits val, \
@ -113,6 +140,30 @@ void btrfs_set_token_##bits(struct extent_buffer *eb, \
token->offset = map_start; \
token->eb = eb; \
} \
} \
void btrfs_set_##bits(struct extent_buffer *eb, void *ptr, \
unsigned long off, u##bits val) \
{ \
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); \
\
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); \
}
DEFINE_BTRFS_SETGET_BITS(8)