btrfs: tie extent buffer and it's token together

Further simplifaction of the get/set helpers is possible when the token
is uniquely tied to an extent buffer. A condition and an assignment can
be avoided.

The initializations are moved closer to the first use when the extent
buffer is valid. There's one exception in __push_leaf_left where the
token is reused.

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c
index 3a29b911d2e2..73f7987143df 100644
--- a/fs/btrfs/struct-funcs.c
+++ b/fs/btrfs/struct-funcs.c
@@ -53,9 +53,9 @@ u##bits btrfs_get_token_##bits(const struct extent_buffer *eb,		\
         u##bits res;                                                    \
                                                                         \
         ASSERT(token);                                                  \
+        ASSERT(token->eb == eb);                                        \
                                                                         \
         if (token->kaddr && token->offset <= offset &&                  \
-            token->eb == eb &&                                          \
            (token->offset + PAGE_SIZE >= offset + size)) {      \
                 kaddr = token->kaddr;                                   \
                 p = kaddr + part_offset - token->offset;                \
@@ -74,7 +74,6 @@ u##bits btrfs_get_token_##bits(const struct extent_buffer *eb,		\
         res = get_unaligned_le##bits(p + off);                          \
         token->kaddr = kaddr;                                           \
         token->offset = map_start;                                      \
-        token->eb = eb;                                                 \
         return res;                                                     \
 }                                                                       \
 u##bits btrfs_get_##bits(const struct extent_buffer *eb,                \
@@ -117,9 +116,9 @@ void btrfs_set_token_##bits(struct extent_buffer *eb,			\
         int size = sizeof(u##bits);                                     \
                                                                         \
         ASSERT(token);                                                  \
+        ASSERT(token->eb == eb);                                        \
                                                                         \
         if (token->kaddr && token->offset <= offset &&                  \
-            token->eb == eb &&                                          \
            (token->offset + PAGE_SIZE >= offset + size)) {      \
                 kaddr = token->kaddr;                                   \
                 p = kaddr + part_offset - token->offset;                \
@@ -139,7 +138,6 @@ void btrfs_set_token_##bits(struct extent_buffer *eb,			\
         put_unaligned_le##bits(val, p + off);                           \
         token->kaddr = kaddr;                                           \
         token->offset = map_start;                                      \
-        token->eb = eb;                                                 \
 }                                                                       \
 void btrfs_set_##bits(struct extent_buffer *eb, void *ptr,              \
                       unsigned long off, u##bits val)                   \