[PATCH 3.2 105/140] dm thin metadata: introduce THIN_MAX_CONCURRENT_LOCKS

[Ben Hutchings]

3.2.100-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Joe Thornber <e...@redhat.com>

commit 8c971178a788c70e8d6db5c3a813de1a1f54e5b7 upstream.

Introduce THIN_MAX_CONCURRENT_LOCKS into dm-thin-metadata to
give a name to an otherwise "magic" number.

Signed-off-by: Joe Thornber <e...@redhat.com>
Signed-off-by: Mike Snitzer <snit...@redhat.com>
Signed-off-by: Alasdair G Kergon <a...@redhat.com>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 drivers/md/dm-thin-metadata.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -80,6 +80,12 @@
 #define THIN_METADATA_CACHE_SIZE 64
 #define SECTOR_TO_BLOCK_SHIFT 3
 
+/*
+ *  3 for btree insert +
+ *  2 for btree lookup used within space map
+ */
+#define THIN_MAX_CONCURRENT_LOCKS 5
+
 /* This should be plenty */
 #define SPACE_MAP_ROOT_SIZE 128
 
@@ -669,13 +675,9 @@ struct dm_pool_metadata *dm_pool_metadat
                return ERR_PTR(-ENOMEM);
        }
 
-       /*
-        * Max hex locks:
-        *  3 for btree insert +
-        *  2 for btree lookup used within space map
-        */
        bm = dm_block_manager_create(bdev, THIN_METADATA_BLOCK_SIZE,
-                                    THIN_METADATA_CACHE_SIZE, 5);
+                                    THIN_METADATA_CACHE_SIZE,
+                                    THIN_MAX_CONCURRENT_LOCKS);
        if (!bm) {
                DMERR("could not create block manager");
                kfree(pmd);