btrfs: struct-funcs, constify readers

We have reader helpers for most of the on-disk structures that use
an extent_buffer and pointer as offset into the buffer that are
read-only.  We should mark them as const and, in turn, allow consumers
of these interfaces to mark the buffers const as well.

No impact on code, but serves as documentation that a buffer is intended
not to be modified.

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

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 5894910409504509bb002e11adba144b0b5d54a4..34ed3dabd43a897caded9caccf3aab9349eb3b67 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1434,7 +1434,7 @@ do {                                                                   \
 #define BTRFS_INODE_ROOT_ITEM_INIT     (1 << 31)
 
 struct btrfs_map_token {
-       struct extent_buffer *eb;
+       const struct extent_buffer *eb;
        char *kaddr;
        unsigned long offset;
 };
@@ -1468,18 +1468,19 @@ static inline void btrfs_init_map_token (struct btrfs_map_token *token)
                           sizeof(((type *)0)->member)))
 
 #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,       \
+u##bits btrfs_get_token_##bits(const struct extent_buffer *eb,         \
+                              const void *ptr, unsigned long off,      \
+                              struct btrfs_map_token *token);          \
+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(struct extent_buffer *eb, void *ptr, \
+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, \
+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);                        \
@@ -1491,7 +1492,8 @@ DECLARE_BTRFS_SETGET_BITS(32)
 DECLARE_BTRFS_SETGET_BITS(64)
 
 #define BTRFS_SETGET_FUNCS(name, type, member, bits)                   \
-static inline u##bits btrfs_##name(struct extent_buffer *eb, type *s)  \
+static inline u##bits btrfs_##name(const struct extent_buffer *eb,     \
+                                  const type *s)                       \
 {                                                                      \
        BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member);   \
        return btrfs_get_##bits(eb, s, offsetof(type, member));         \
@@ -1502,7 +1504,8 @@ static inline void btrfs_set_##name(struct extent_buffer *eb, type *s,    \
        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, \
+static inline u##bits btrfs_token_##name(const struct extent_buffer *eb,\
+                                        const type *s,                 \
                                         struct btrfs_map_token *token) \
 {                                                                      \
        BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member);   \
@@ -1517,9 +1520,9 @@ static inline void btrfs_set_token_##name(struct extent_buffer *eb,       \
 }
 
 #define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits)            \
-static inline u##bits btrfs_##name(struct extent_buffer *eb)           \
+static inline u##bits btrfs_##name(const struct extent_buffer *eb)     \
 {                                                                      \
-       type *p = page_address(eb->pages[0]);                           \
+       const type *p = page_address(eb->pages[0]);                     \
        u##bits res = le##bits##_to_cpu(p->member);                     \
        return res;                                                     \
 }                                                                      \
@@ -1531,7 +1534,7 @@ static inline void btrfs_set_##name(struct extent_buffer *eb,             \
 }
 
 #define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits)             \
-static inline u##bits btrfs_##name(type *s)                            \
+static inline u##bits btrfs_##name(const type *s)                      \
 {                                                                      \
        return le##bits##_to_cpu(s->member);                            \
 }                                                                      \
@@ -1856,7 +1859,7 @@ static inline unsigned long btrfs_node_key_ptr_offset(int nr)
                sizeof(struct btrfs_key_ptr) * nr;
 }
 
-void btrfs_node_key(struct extent_buffer *eb,
+void btrfs_node_key(const struct extent_buffer *eb,
                    struct btrfs_disk_key *disk_key, int nr);
 
 static inline void btrfs_set_node_key(struct extent_buffer *eb,
@@ -1885,28 +1888,28 @@ static inline struct btrfs_item *btrfs_item_nr(int nr)
        return (struct btrfs_item *)btrfs_item_nr_offset(nr);
 }
 
-static inline u32 btrfs_item_end(struct extent_buffer *eb,
+static inline u32 btrfs_item_end(const struct extent_buffer *eb,
                                 struct btrfs_item *item)
 {
        return btrfs_item_offset(eb, item) + btrfs_item_size(eb, item);
 }
 
-static inline u32 btrfs_item_end_nr(struct extent_buffer *eb, int nr)
+static inline u32 btrfs_item_end_nr(const struct extent_buffer *eb, int nr)
 {
        return btrfs_item_end(eb, btrfs_item_nr(nr));
 }
 
-static inline u32 btrfs_item_offset_nr(struct extent_buffer *eb, int nr)
+static inline u32 btrfs_item_offset_nr(const struct extent_buffer *eb, int nr)
 {
        return btrfs_item_offset(eb, btrfs_item_nr(nr));
 }
 
-static inline u32 btrfs_item_size_nr(struct extent_buffer *eb, int nr)
+static inline u32 btrfs_item_size_nr(const struct extent_buffer *eb, int nr)
 {
        return btrfs_item_size(eb, btrfs_item_nr(nr));
 }
 
-static inline void btrfs_item_key(struct extent_buffer *eb,
+static inline void btrfs_item_key(const struct extent_buffer *eb,
                           struct btrfs_disk_key *disk_key, int nr)
 {
        struct btrfs_item *item = btrfs_item_nr(nr);
@@ -1942,8 +1945,8 @@ BTRFS_SETGET_STACK_FUNCS(stack_dir_name_len, struct btrfs_dir_item,
 BTRFS_SETGET_STACK_FUNCS(stack_dir_transid, struct btrfs_dir_item,
                         transid, 64);
 
-static inline void btrfs_dir_item_key(struct extent_buffer *eb,
-                                     struct btrfs_dir_item *item,
+static inline void btrfs_dir_item_key(const struct extent_buffer *eb,
+                                     const struct btrfs_dir_item *item,
                                      struct btrfs_disk_key *key)
 {
        read_eb_member(eb, item, struct btrfs_dir_item, location, key);
@@ -1951,7 +1954,7 @@ static inline void btrfs_dir_item_key(struct extent_buffer *eb,
 
 static inline void btrfs_set_dir_item_key(struct extent_buffer *eb,
                                          struct btrfs_dir_item *item,
-                                         struct btrfs_disk_key *key)
+                                         const struct btrfs_disk_key *key)
 {
        write_eb_member(eb, item, struct btrfs_dir_item, location, key);
 }
@@ -1963,8 +1966,8 @@ BTRFS_SETGET_FUNCS(free_space_bitmaps, struct btrfs_free_space_header,
 BTRFS_SETGET_FUNCS(free_space_generation, struct btrfs_free_space_header,
                   generation, 64);
 
-static inline void btrfs_free_space_key(struct extent_buffer *eb,
-                                       struct btrfs_free_space_header *h,
+static inline void btrfs_free_space_key(const struct extent_buffer *eb,
+                                       const struct btrfs_free_space_header *h,
                                        struct btrfs_disk_key *key)
 {
        read_eb_member(eb, h, struct btrfs_free_space_header, location, key);
@@ -1972,7 +1975,7 @@ static inline void btrfs_free_space_key(struct extent_buffer *eb,
 
 static inline void btrfs_set_free_space_key(struct extent_buffer *eb,
                                            struct btrfs_free_space_header *h,
-                                           struct btrfs_disk_key *key)
+                                           const struct btrfs_disk_key *key)
 {
        write_eb_member(eb, h, struct btrfs_free_space_header, location, key);
 }
@@ -1999,25 +2002,25 @@ static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk,
        disk->objectid = cpu_to_le64(cpu->objectid);
 }
 
-static inline void btrfs_node_key_to_cpu(struct extent_buffer *eb,
-                                 struct btrfs_key *key, int nr)
+static inline void btrfs_node_key_to_cpu(const struct extent_buffer *eb,
+                                        struct btrfs_key *key, int nr)
 {
        struct btrfs_disk_key disk_key;
        btrfs_node_key(eb, &disk_key, nr);
        btrfs_disk_key_to_cpu(key, &disk_key);
 }
 
-static inline void btrfs_item_key_to_cpu(struct extent_buffer *eb,
-                                 struct btrfs_key *key, int nr)
+static inline void btrfs_item_key_to_cpu(const struct extent_buffer *eb,
+                                        struct btrfs_key *key, int nr)
 {
        struct btrfs_disk_key disk_key;
        btrfs_item_key(eb, &disk_key, nr);
        btrfs_disk_key_to_cpu(key, &disk_key);
 }
 
-static inline void btrfs_dir_item_key_to_cpu(struct extent_buffer *eb,
-                                     struct btrfs_dir_item *item,
-                                     struct btrfs_key *key)
+static inline void btrfs_dir_item_key_to_cpu(const struct extent_buffer *eb,
+                                            const struct btrfs_dir_item *item,
+                                            struct btrfs_key *key)
 {
        struct btrfs_disk_key disk_key;
        btrfs_dir_item_key(eb, item, &disk_key);
@@ -2049,7 +2052,7 @@ BTRFS_SETGET_STACK_FUNCS(stack_header_nritems, struct btrfs_header,
                         nritems, 32);
 BTRFS_SETGET_STACK_FUNCS(stack_header_bytenr, struct btrfs_header, bytenr, 64);
 
-static inline int btrfs_header_flag(struct extent_buffer *eb, u64 flag)
+static inline int btrfs_header_flag(const struct extent_buffer *eb, u64 flag)
 {
        return (btrfs_header_flags(eb) & flag) == flag;
 }
@@ -2068,7 +2071,7 @@ static inline int btrfs_clear_header_flag(struct extent_buffer *eb, u64 flag)
        return (flags & flag) == flag;
 }
 
-static inline int btrfs_header_backref_rev(struct extent_buffer *eb)
+static inline int btrfs_header_backref_rev(const struct extent_buffer *eb)
 {
        u64 flags = btrfs_header_flags(eb);
        return flags >> BTRFS_BACKREF_REV_SHIFT;
@@ -2088,12 +2091,12 @@ static inline unsigned long btrfs_header_fsid(void)
        return offsetof(struct btrfs_header, fsid);
 }
 
-static inline unsigned long btrfs_header_chunk_tree_uuid(struct extent_buffer *eb)
+static inline unsigned long btrfs_header_chunk_tree_uuid(const struct extent_buffer *eb)
 {
        return offsetof(struct btrfs_header, chunk_tree_uuid);
 }
 
-static inline int btrfs_is_leaf(struct extent_buffer *eb)
+static inline int btrfs_is_leaf(const struct extent_buffer *eb)
 {
        return btrfs_header_level(eb) == 0;
 }
@@ -2127,12 +2130,12 @@ BTRFS_SETGET_STACK_FUNCS(root_stransid, struct btrfs_root_item,
 BTRFS_SETGET_STACK_FUNCS(root_rtransid, struct btrfs_root_item,
                         rtransid, 64);
 
-static inline bool btrfs_root_readonly(struct btrfs_root *root)
+static inline bool btrfs_root_readonly(const struct btrfs_root *root)
 {
        return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
 }
 
-static inline bool btrfs_root_dead(struct btrfs_root *root)
+static inline bool btrfs_root_dead(const struct btrfs_root *root)
 {
        return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
 }
@@ -2189,51 +2192,51 @@ BTRFS_SETGET_STACK_FUNCS(backup_num_devices, struct btrfs_root_backup,
 /* struct btrfs_balance_item */
 BTRFS_SETGET_FUNCS(balance_flags, struct btrfs_balance_item, flags, 64);
 
-static inline void btrfs_balance_data(struct extent_buffer *eb,
-                                     struct btrfs_balance_item *bi,
+static inline void btrfs_balance_data(const struct extent_buffer *eb,
+                                     const struct btrfs_balance_item *bi,
                                      struct btrfs_disk_balance_args *ba)
 {
        read_eb_member(eb, bi, struct btrfs_balance_item, data, ba);
 }
 
 static inline void btrfs_set_balance_data(struct extent_buffer *eb,
-                                         struct btrfs_balance_item *bi,
-                                         struct btrfs_disk_balance_args *ba)
+                                 struct btrfs_balance_item *bi,
+                                 const struct btrfs_disk_balance_args *ba)
 {
        write_eb_member(eb, bi, struct btrfs_balance_item, data, ba);
 }
 
-static inline void btrfs_balance_meta(struct extent_buffer *eb,
-                                     struct btrfs_balance_item *bi,
+static inline void btrfs_balance_meta(const struct extent_buffer *eb,
+                                     const struct btrfs_balance_item *bi,
                                      struct btrfs_disk_balance_args *ba)
 {
        read_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);
 }
 
 static inline void btrfs_set_balance_meta(struct extent_buffer *eb,
-                                         struct btrfs_balance_item *bi,
-                                         struct btrfs_disk_balance_args *ba)
+                                 struct btrfs_balance_item *bi,
+                                 const struct btrfs_disk_balance_args *ba)
 {
        write_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);
 }
 
-static inline void btrfs_balance_sys(struct extent_buffer *eb,
-                                    struct btrfs_balance_item *bi,
+static inline void btrfs_balance_sys(const struct extent_buffer *eb,
+                                    const struct btrfs_balance_item *bi,
                                     struct btrfs_disk_balance_args *ba)
 {
        read_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);
 }
 
 static inline void btrfs_set_balance_sys(struct extent_buffer *eb,
-                                        struct btrfs_balance_item *bi,
-                                        struct btrfs_disk_balance_args *ba)
+                                struct btrfs_balance_item *bi,
+                                const struct btrfs_disk_balance_args *ba)
 {
        write_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);
 }
 
 static inline void
 btrfs_disk_balance_args_to_cpu(struct btrfs_balance_args *cpu,
-                              struct btrfs_disk_balance_args *disk)
+                              const struct btrfs_disk_balance_args *disk)
 {
        memset(cpu, 0, sizeof(*cpu));
 
@@ -2253,7 +2256,7 @@ btrfs_disk_balance_args_to_cpu(struct btrfs_balance_args *cpu,
 
 static inline void
 btrfs_cpu_balance_args_to_disk(struct btrfs_disk_balance_args *disk,
-                              struct btrfs_balance_args *cpu)
+                              const struct btrfs_balance_args *cpu)
 {
        memset(disk, 0, sizeof(*disk));
 
@@ -2321,7 +2324,7 @@ BTRFS_SETGET_STACK_FUNCS(super_magic, struct btrfs_super_block, magic, 64);
 BTRFS_SETGET_STACK_FUNCS(super_uuid_tree_generation, struct btrfs_super_block,
                         uuid_tree_generation, 64);
 
-static inline int btrfs_super_csum_size(struct btrfs_super_block *s)
+static inline int btrfs_super_csum_size(const struct btrfs_super_block *s)
 {
        u16 t = btrfs_super_csum_type(s);
        /*
@@ -2336,8 +2339,8 @@ static inline int btrfs_super_csum_size(struct btrfs_super_block *s)
  * this returns the address of the start of the last item,
  * which is the stop of the leaf data stack
  */
-static inline unsigned int leaf_data_end(struct btrfs_fs_info *fs_info,
-                                        struct extent_buffer *leaf)
+static inline unsigned int leaf_data_end(const struct btrfs_fs_info *fs_info,
+                                        const struct extent_buffer *leaf)
 {
        u32 nr = btrfs_header_nritems(leaf);
 
@@ -2362,7 +2365,7 @@ BTRFS_SETGET_STACK_FUNCS(stack_file_extent_compression,
                         struct btrfs_file_extent_item, compression, 8);
 
 static inline unsigned long
-btrfs_file_extent_inline_start(struct btrfs_file_extent_item *e)
+btrfs_file_extent_inline_start(const struct btrfs_file_extent_item *e)
 {
        return (unsigned long)e + BTRFS_FILE_EXTENT_INLINE_DATA_START;
 }
@@ -2396,8 +2399,9 @@ BTRFS_SETGET_FUNCS(file_extent_other_encoding, struct btrfs_file_extent_item,
  * size of any extent headers.  If a file is compressed on disk, this is
  * the compressed size
  */
-static inline u32 btrfs_file_extent_inline_item_len(struct extent_buffer *eb,
-                                                   struct btrfs_item *e)
+static inline u32 btrfs_file_extent_inline_item_len(
+                                               const struct extent_buffer *eb,
+                                               struct btrfs_item *e)
 {
        return btrfs_item_size(eb, e) - BTRFS_FILE_EXTENT_INLINE_DATA_START;
 }
@@ -2405,9 +2409,9 @@ static inline u32 btrfs_file_extent_inline_item_len(struct extent_buffer *eb,
 /* this returns the number of file bytes represented by the inline item.
  * If an item is compressed, this is the uncompressed size
  */
-static inline u32 btrfs_file_extent_inline_len(struct extent_buffer *eb,
-                                              int slot,
-                                              struct btrfs_file_extent_item *fi)
+static inline u32 btrfs_file_extent_inline_len(const struct extent_buffer *eb,
+                                       int slot,
+                                       const struct btrfs_file_extent_item *fi)
 {
        struct btrfs_map_token token;
 
@@ -2429,8 +2433,8 @@ static inline u32 btrfs_file_extent_inline_len(struct extent_buffer *eb,
 
 
 /* btrfs_dev_stats_item */
-static inline u64 btrfs_dev_stats_value(struct extent_buffer *eb,
-                                       struct btrfs_dev_stats_item *ptr,
+static inline u64 btrfs_dev_stats_value(const struct extent_buffer *eb,
+                                       const struct btrfs_dev_stats_item *ptr,
                                        int index)
 {
        u64 val;

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0aff9b278c1990f55feb2693a9fff65d5bf693ed..d6f761b4fae0f70692386d5d30cc34f83f1778e2 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -5405,9 +5405,8 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
        return ret;
 }
 
-void read_extent_buffer(struct extent_buffer *eb, void *dstv,
-                       unsigned long start,
-                       unsigned long len)
+void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
+                       unsigned long start, unsigned long len)
 {
        size_t cur;
        size_t offset;
@@ -5436,9 +5435,9 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
        }
 }
 
-int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
-                       unsigned long start,
-                       unsigned long len)
+int read_extent_buffer_to_user(const struct extent_buffer *eb,
+                              void __user *dstv,
+                              unsigned long start, unsigned long len)
 {
        size_t cur;
        size_t offset;
@@ -5478,10 +5477,10 @@ int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
  * return 1 if the item spans two pages.
  * return -EINVAL otherwise.
  */
-int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
-                              unsigned long min_len, char **map,
-                              unsigned long *map_start,
-                              unsigned long *map_len)
+int map_private_extent_buffer(const struct extent_buffer *eb,
+                             unsigned long start, unsigned long min_len,
+                             char **map, unsigned long *map_start,
+                             unsigned long *map_len)
 {
        size_t offset = start & (PAGE_SIZE - 1);
        char *kaddr;
@@ -5515,9 +5514,8 @@ int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
        return 0;
 }
 
-int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
-                         unsigned long start,
-                         unsigned long len)
+int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
+                        unsigned long start, unsigned long len)
 {
        size_t cur;
        size_t offset;

diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 4f030912f3efe784cfec3117a4459c07d77518c8..faffa28ba707f3733e841aff16b02da259730249 100644 (file)
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -449,14 +449,13 @@ static inline void extent_buffer_get(struct extent_buffer *eb)
        atomic_inc(&eb->refs);
 }
 
-int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
-                         unsigned long start,
-                         unsigned long len);
-void read_extent_buffer(struct extent_buffer *eb, void *dst,
+int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
+                        unsigned long start, unsigned long len);
+void read_extent_buffer(const struct extent_buffer *eb, void *dst,
                        unsigned long start,
                        unsigned long len);
-int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dst,
-                              unsigned long start,
+int read_extent_buffer_to_user(const struct extent_buffer *eb,
+                              void __user *dst, unsigned long start,
                               unsigned long len);
 void write_extent_buffer_fsid(struct extent_buffer *eb, const void *src);
 void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
@@ -486,10 +485,10 @@ void set_extent_buffer_uptodate(struct extent_buffer *eb);
 void clear_extent_buffer_uptodate(struct extent_buffer *eb);
 int extent_buffer_uptodate(struct extent_buffer *eb);
 int extent_buffer_under_io(struct extent_buffer *eb);
-int map_private_extent_buffer(struct extent_buffer *eb, unsigned long offset,
-                     unsigned long min_len, char **map,
-                     unsigned long *map_start,
-                     unsigned long *map_len);
+int map_private_extent_buffer(const struct extent_buffer *eb,
+                             unsigned long offset, unsigned long min_len,
+                             char **map, unsigned long *map_start,
+                             unsigned long *map_len);
 void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end);
 void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end);
 void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,

diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c
index 875c757e73e2a8eacae1d9817bd83d56d32b21cf..5e2b92d8361735fb27d2b17ff132439821b4fb34 100644 (file)
--- a/fs/btrfs/struct-funcs.c
+++ b/fs/btrfs/struct-funcs.c
@@ -50,8 +50,8 @@ static inline void put_unaligned_le8(u8 val, void *p)
  */
 
 #define DEFINE_BTRFS_SETGET_BITS(bits)                                 \
-u##bits btrfs_get_token_##bits(struct extent_buffer *eb, void *ptr,    \
-                              unsigned long off,                       \
+u##bits btrfs_get_token_##bits(const struct extent_buffer *eb,         \
+                              const void *ptr, unsigned long off,      \
                               struct btrfs_map_token *token)           \
 {                                                                      \
        unsigned long part_offset = (unsigned long)ptr;                 \
@@ -90,7 +90,8 @@ u##bits btrfs_get_token_##bits(struct extent_buffer *eb, void *ptr,   \
        return res;                                                     \
 }                                                                      \
 void btrfs_set_token_##bits(struct extent_buffer *eb,                  \
-                           void *ptr, unsigned long off, u##bits val,  \
+                           const void *ptr, unsigned long off,         \
+                           u##bits val,                                \
                            struct btrfs_map_token *token)              \
 {                                                                      \
        unsigned long part_offset = (unsigned long)ptr;                 \
@@ -133,7 +134,7 @@ DEFINE_BTRFS_SETGET_BITS(16)
 DEFINE_BTRFS_SETGET_BITS(32)
 DEFINE_BTRFS_SETGET_BITS(64)
 
-void btrfs_node_key(struct extent_buffer *eb,
+void btrfs_node_key(const struct extent_buffer *eb,
                    struct btrfs_disk_key *disk_key, int nr)
 {
        unsigned long ptr = btrfs_node_key_ptr_offset(nr);