bcache: only use bucket_bytes() on struct cache

Because struct cache_set and struct cache both have struct cache_sb,
macro bucket_bytes() currently are used on both of them. When removing
the embedded struct cache_sb from struct cache_set, this macro won't be
used on struct cache_set anymore.

This patch unifies all bucket_bytes() usage only on struct cache, this is
one of the preparation to remove the embedded struct cache_sb from
struct cache_set.
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/bcache/bcache.h

@@ -757,7 +757,7 @@ struct bbio {
 #define btree_default_blocks(c)						\
 	((unsigned int) ((PAGE_SECTORS * (c)->btree_pages) >> (c)->block_bits))
 
-#define bucket_bytes(c)		((c)->sb.bucket_size << 9)
+#define bucket_bytes(ca)	((ca)->sb.bucket_size << 9)
 #define block_bytes(ca)		((ca)->sb.block_size << 9)
 
 static inline unsigned int meta_bucket_pages(struct cache_sb *sb)

drivers/md/bcache/sysfs.c

@@ -713,7 +713,7 @@ SHOW(__bch_cache_set)
 
 	sysfs_print(synchronous,		CACHE_SYNC(&c->sb));
 	sysfs_print(journal_delay_ms,		c->journal_delay_ms);
-	sysfs_hprint(bucket_size,		bucket_bytes(c));
+	sysfs_hprint(bucket_size,		bucket_bytes(c->cache));
 	sysfs_hprint(block_size,		block_bytes(c->cache));
 	sysfs_print(tree_depth,			c->root->level);
 	sysfs_print(root_usage_percent,		bch_root_usage(c));