[PATCH v5 2/4] btrfs: create structure to encode checksum type and length

[Johannes Thumshirn]

Create a structure to encode the type and length for the known on-disk
checksums.

This makes it easier to add new checksums later.

Signed-off-by: Johannes Thumshirn <jthumsh...@suse.de>
Reviewed-by: Nikolay Borisov <nbori...@suse.com>

---
Changes to v4:
- Move table and accessor functions from ctree.h to ctree.c

Changes to v2:
- Really remove initializer macro *doh*

Changes to v1:
- Remove initializer macro (David)
---
 fs/btrfs/ctree.c | 22 ++++++++++++++++++++++
 fs/btrfs/ctree.h | 20 ++------------------
 2 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index a2f3cd7a619c..9c36b1a878ec 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -29,6 +29,28 @@ static int balance_node_right(struct btrfs_trans_handle 
*trans,
 static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
                    int level, int slot);
 
+static const struct btrfs_csums {
+       u16             size;
+       const char      *name;
+} btrfs_csums[] = {
+       [BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" },
+};
+
+int btrfs_super_csum_size(const struct btrfs_super_block *s)
+{
+       u16 t = btrfs_super_csum_type(s);
+       /*
+        * csum type is validated at mount time
+        */
+       return btrfs_csums[t].size;
+}
+
+const char *btrfs_super_csum_name(u16 csum_type)
+{
+       /* csum type is validated at mount time */
+       return btrfs_csums[csum_type].name;
+}
+
 struct btrfs_path *btrfs_alloc_path(void)
 {
        return kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d27b39858339..2359480749e1 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -82,10 +82,6 @@ struct btrfs_ref;
  */
 #define BTRFS_LINK_MAX 65535U
 
-/* four bytes for CRC32 */
-static const int btrfs_csum_sizes[] = { 4 };
-static const char *btrfs_csum_names[] = { "crc32c" };
-
 #define BTRFS_EMPTY_DIR_SIZE 0
 
 /* ioprio of readahead is set to idle */
@@ -2201,20 +2197,8 @@ 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(const struct btrfs_super_block *s)
-{
-       u16 t = btrfs_super_csum_type(s);
-       /*
-        * csum type is validated at mount time
-        */
-       return btrfs_csum_sizes[t];
-}
-
-static inline const char *btrfs_super_csum_name(u16 csum_type)
-{
-       /* csum type is validated at mount time */
-       return btrfs_csum_names[csum_type];
-}
+int btrfs_super_csum_size(const struct btrfs_super_block *s);
+const char *btrfs_super_csum_name(u16 csum_type);
 
 /*
  * The leaf data grows from end-to-front in the node.
-- 
2.16.4