btrfs: define separate btrfs_set/get_XX helpers
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>
diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c
index 4c13b73..e63936e 100644
--- a/fs/btrfs/struct-funcs.c
+++ b/fs/btrfs/struct-funcs.c
@@ -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)
