dm cache metadata: use dm-space-map-metadata.h defined size limits

Commit 7d48935e cleaned up the persistent-data's space-map-metadata
limits by elevating them to dm-space-map-metadata.h.  Update
dm-cache-metadata to use these same limits.

The calculation for DM_CACHE_METADATA_MAX_SECTORS didn't account for the
sizeof the disk_bitmap_header.  So the supported maximum metadata size
is a bit smaller (reduced from 33423360 to 33292800 sectors).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>

drivers/md/dm-cache-metadata.c

@@ -330,7 +330,7 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd)
 	disk_super->discard_root = cpu_to_le64(cmd->discard_root);
 	disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
 	disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks));
-	disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
+	disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
 	disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
 	disk_super->cache_blocks = cpu_to_le32(0);
 
@@ -478,7 +478,7 @@ static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
 					    bool may_format_device)
 {
 	int r;
-	cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE,
+	cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
 					  CACHE_METADATA_CACHE_SIZE,
 					  CACHE_MAX_CONCURRENT_LOCKS);
 	if (IS_ERR(cmd->bm)) {

drivers/md/dm-cache-metadata.h

@@ -9,19 +9,17 @@
 
 #include "dm-cache-block-types.h"
 #include "dm-cache-policy-internal.h"
+#include "persistent-data/dm-space-map-metadata.h"
 
 /*----------------------------------------------------------------*/
 
-#define DM_CACHE_METADATA_BLOCK_SIZE 4096
+#define DM_CACHE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE
 
 /* FIXME: remove this restriction */
 /*
  * The metadata device is currently limited in size.
- *
- * We have one block of index, which can hold 255 index entries.  Each
- * index entry contains allocation info about 16k metadata blocks.
  */
-#define DM_CACHE_METADATA_MAX_SECTORS (255 * (1 << 14) * (DM_CACHE_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT)))
+#define DM_CACHE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS
 
 /*
  * A metadata device larger than 16GB triggers a warning.

drivers/md/dm-cache-target.c

@@ -2840,7 +2840,7 @@ static void cache_status(struct dm_target *ti, status_type_t type,
 		residency = policy_residency(cache->policy);
 
 		DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %lu ",
-		       (unsigned)(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
+		       (unsigned)DM_CACHE_METADATA_BLOCK_SIZE,
 		       (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
 		       (unsigned long long)nr_blocks_metadata,
 		       cache->sectors_per_block,