5 files changed, 17 insertions, 3 deletions

diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt
index 63fd7cfa4cf1..e6b72d355151 100644
--- a/Documentation/device-mapper/cache.txt
+++ b/Documentation/device-mapper/cache.txt
@@ -221,7 +221,7 @@ Status
 <cache block size> <#used cache blocks>/<#total cache blocks>
 <#read hits> <#read misses> <#write hits> <#write misses>
 <#demotions> <#promotions> <#dirty> <#features> <features>*
-<#core args> <core args>* <#policy args> <policy args>*
+<#core args> <core args>* <policy name> <#policy args> <policy args>*
 
 metadata block size      : Fixed block size for each metadata block in
                              sectors
@@ -250,6 +250,7 @@ feature args		 : 'writethrough' (optional)
 #core args               : Number of core arguments (must be even)
 core args                : Key/value pairs for tuning the core
                              e.g. migration_threshold
+policy name              : Name of the policy
 #policy args             : Number of policy arguments to follow (must be even)
 policy args              : Key/value pairs
                              e.g. sequential_threshold
diff --git a/drivers/md/dm-cache-policy-mq.c b/drivers/md/dm-cache-policy-mq.c
index e63e36cefc89..930e8c3d73e9 100644
--- a/drivers/md/dm-cache-policy-mq.c
+++ b/drivers/md/dm-cache-policy-mq.c
@@ -1276,7 +1276,8 @@ static struct dm_cache_policy_type default_policy_type = {
         .version = {1, 2, 0},
         .hint_size = 4,
         .owner = THIS_MODULE,
-        .create = mq_create
+        .create = mq_create,
+        .real = &mq_policy_type
 };
 
 static int __init mq_init(void)
diff --git a/drivers/md/dm-cache-policy.c b/drivers/md/dm-cache-policy.c
index d80057968407..c1a3cee99b44 100644
--- a/drivers/md/dm-cache-policy.c
+++ b/drivers/md/dm-cache-policy.c
@@ -146,6 +146,10 @@ const char *dm_cache_policy_get_name(struct dm_cache_policy *p)
 {
         struct dm_cache_policy_type *t = p->private;
 
+        /* if t->real is set then an alias was used (e.g. "default") */
+        if (t->real)
+                return t->real->name;
+
         return t->name;
 }
 EXPORT_SYMBOL_GPL(dm_cache_policy_get_name);
diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h
index 052c00a84a5c..f50fe360c546 100644
--- a/drivers/md/dm-cache-policy.h
+++ b/drivers/md/dm-cache-policy.h
@@ -223,6 +223,12 @@ struct dm_cache_policy_type {
         unsigned version[CACHE_POLICY_VERSION_SIZE];
 
         /*
+         * For use by an alias dm_cache_policy_type to point to the
+         * real dm_cache_policy_type.
+         */
+        struct dm_cache_policy_type *real;
+
+        /*
          * Policies may store a hint for each each cache block.
          * Currently the size of this hint must be 0 or 4 bytes but we
          * expect to relax this in future.
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 11ad70540d40..09334c275c79 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2832,7 +2832,7 @@ static void cache_resume(struct dm_target *ti)
  * <#demotions> <#promotions> <#dirty>
  * <#features> <features>*
  * <#core args> <core args>
- * <#policy args> <policy args>*
+ * <policy name> <#policy args> <policy args>*
  */
 static void cache_status(struct dm_target *ti, status_type_t type,
                          unsigned status_flags, char *result, unsigned maxlen)
@@ -2900,6 +2900,8 @@ static void cache_status(struct dm_target *ti, status_type_t type,
                 }
 
                 DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
+
+                DMEMIT("%s ", dm_cache_policy_get_name(cache->policy));
                 if (sz < maxlen) {
                         r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz);
                         if (r)