[PATCH 4.9 072/101] btrfs: struct-funcs, constify readers

4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jeff Mahoney jeffm@suse.com

commit 1cbb1f454e5321e47fc1e6b233066c7ccc979d15 upstream.

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 Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/ctree.h | 128 ++++++++++++++++++++++++------------------------ fs/btrfs/extent_io.c | 24 ++++----- fs/btrfs/extent_io.h | 19 +++---- fs/btrfs/struct-funcs.c | 9 +-- 4 files changed, 91 insertions(+), 89 deletions(-)

--- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1415,7 +1415,7 @@ 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; }; @@ -1449,18 +1449,19 @@ static inline void btrfs_init_map_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); \ @@ -1472,7 +1473,8 @@ 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)); \ @@ -1483,7 +1485,8 @@ static inline void btrfs_set_##name(stru 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); \ @@ -1498,9 +1501,9 @@ static inline void btrfs_set_token_##nam }

#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; \ } \ @@ -1512,7 +1515,7 @@ static inline void btrfs_set_##name(stru }

#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); \ } \ @@ -1818,7 +1821,7 @@ static inline unsigned long btrfs_node_k 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, @@ -1847,28 +1850,28 @@ static inline struct btrfs_item *btrfs_i 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); @@ -1904,8 +1907,8 @@ BTRFS_SETGET_STACK_FUNCS(stack_dir_name_ 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); @@ -1913,7 +1916,7 @@ static inline void btrfs_dir_item_key(st

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); } @@ -1925,8 +1928,8 @@ BTRFS_SETGET_FUNCS(free_space_bitmaps, s 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); @@ -1934,7 +1937,7 @@ static inline void btrfs_free_space_key(

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); } @@ -1961,25 +1964,25 @@ static inline void btrfs_cpu_key_to_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); @@ -2012,7 +2015,7 @@ BTRFS_SETGET_STACK_FUNCS(stack_header_nr 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; } @@ -2031,7 +2034,7 @@ static inline int btrfs_clear_header_fla 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; @@ -2051,12 +2054,12 @@ static inline unsigned long btrfs_header 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; } @@ -2090,12 +2093,12 @@ BTRFS_SETGET_STACK_FUNCS(root_stransid, 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; } @@ -2152,51 +2155,51 @@ BTRFS_SETGET_STACK_FUNCS(backup_num_devi /* 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));

@@ -2216,7 +2219,7 @@ btrfs_disk_balance_args_to_cpu(struct bt

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));

@@ -2284,7 +2287,7 @@ BTRFS_SETGET_STACK_FUNCS(super_magic, st 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); /* @@ -2303,8 +2306,8 @@ static inline unsigned long btrfs_leaf_d * 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_root *root, - struct extent_buffer *leaf) +static inline unsigned int leaf_data_end(const struct btrfs_root *root, + const struct extent_buffer *leaf) { u32 nr = btrfs_header_nritems(leaf);

@@ -2329,7 +2332,7 @@ BTRFS_SETGET_STACK_FUNCS(stack_file_exte 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; } @@ -2363,8 +2366,9 @@ BTRFS_SETGET_FUNCS(file_extent_other_enc * 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; } @@ -2372,9 +2376,9 @@ static inline u32 btrfs_file_extent_inli /* 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;

@@ -2396,8 +2400,8 @@ static inline u32 btrfs_file_extent_inli

/* 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; --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -5442,9 +5442,8 @@ unlock_exit: 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; @@ -5473,9 +5472,9 @@ void read_extent_buffer(struct extent_bu } }

-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; @@ -5515,10 +5514,10 @@ int read_extent_buffer_to_user(struct ex * 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; @@ -5552,9 +5551,8 @@ int map_private_extent_buffer(struct ext 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; --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -396,14 +396,13 @@ static inline void extent_buffer_get(str 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(struct extent_buffer *eb, const void *src, unsigned long start, unsigned long len); @@ -428,10 +427,10 @@ void set_extent_buffer_uptodate(struct e 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, --- a/fs/btrfs/struct-funcs.c +++ b/fs/btrfs/struct-funcs.c @@ -50,8 +50,8 @@ static inline void put_unaligned_le8(u8 */

#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 ex 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);