dm cache: set config value

Share configuration option processing code between the dm cache
ctr and message functions.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

drivers/md/dm-cache-target.c

@@ -1813,12 +1813,12 @@ static struct kmem_cache *migration_cache;
 
 #define NOT_CORE_OPTION 1
 
-static int process_config_option(struct cache *cache, char **argv)
+static int process_config_option(struct cache *cache, const char *key, const char *value)
 {
 	unsigned long tmp;
 
-	if (!strcasecmp(argv[0], "migration_threshold")) {
-		if (kstrtoul(argv[1], 10, &tmp))
+	if (!strcasecmp(key, "migration_threshold")) {
+		if (kstrtoul(value, 10, &tmp))
 			return -EINVAL;
 
 		cache->migration_threshold = tmp;
@@ -1828,7 +1828,20 @@ static int process_config_option(struct cache *cache, char **argv)
 	return NOT_CORE_OPTION;
 }
 
-static int set_config_values(struct dm_cache_policy *p, int argc, const char **argv)
+static int set_config_value(struct cache *cache, const char *key, const char *value)
+{
+	int r = process_config_option(cache, key, value);
+
+	if (r == NOT_CORE_OPTION)
+		r = policy_set_config_value(cache->policy, key, value);
+
+	if (r)
+		DMWARN("bad config value for %s: %s", key, value);
+
+	return r;
+}
+
+static int set_config_values(struct cache *cache, int argc, const char **argv)
 {
 	int r = 0;
 
@@ -1838,12 +1851,9 @@ static int set_config_values(struct dm_cache_policy *p, int argc, const char **a
 	}
 
 	while (argc) {
-		r = policy_set_config_value(p, argv[0], argv[1]);
-		if (r) {
-			DMWARN("policy_set_config_value failed: key = '%s', value = '%s'",
-			       argv[0], argv[1]);
-			return r;
-		}
+		r = set_config_value(cache, argv[0], argv[1]);
+		if (r)
+			break;
 
 		argc -= 2;
 		argv += 2;
@@ -1855,8 +1865,6 @@ static int set_config_values(struct dm_cache_policy *p, int argc, const char **a
 static int create_cache_policy(struct cache *cache, struct cache_args *ca,
 			       char **error)
 {
-	int r;
-
 	cache->policy =	dm_cache_policy_create(ca->policy_name,
 					       cache->cache_size,
 					       cache->origin_sectors,
@@ -1866,14 +1874,7 @@ static int create_cache_policy(struct cache *cache, struct cache_args *ca,
 		return -ENOMEM;
 	}
 
-	r = set_config_values(cache->policy, ca->policy_argc, ca->policy_argv);
-	if (r) {
-		*error = "Error setting cache policy's config values";
-		dm_cache_policy_destroy(cache->policy);
-		cache->policy = NULL;
-	}
-
-	return r;
+	return 0;
 }
 
 /*
@@ -1967,7 +1968,15 @@ static int cache_create(struct cache_args *ca, struct cache **result)
 	r = create_cache_policy(cache, ca, error);
 	if (r)
 		goto bad;
+
 	cache->policy_nr_args = ca->policy_argc;
+	cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD;
+
+	r = set_config_values(cache, ca->policy_argc, ca->policy_argv);
+	if (r) {
+		*error = "Error setting cache policy's config values";
+		goto bad;
+	}
 
 	cmd = dm_cache_metadata_open(cache->metadata_dev->bdev,
 				     ca->block_size, may_format,
@@ -1986,7 +1995,6 @@ static int cache_create(struct cache_args *ca, struct cache **result)
 	INIT_LIST_HEAD(&cache->quiesced_migrations);
 	INIT_LIST_HEAD(&cache->completed_migrations);
 	INIT_LIST_HEAD(&cache->need_commit_migrations);
-	cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD;
 	atomic_set(&cache->nr_migrations, 0);
 	init_waitqueue_head(&cache->migration_wait);
 
@@ -2544,17 +2552,12 @@ static void cache_status(struct dm_target *ti, status_type_t type,
  */
 static int cache_message(struct dm_target *ti, unsigned argc, char **argv)
 {
-	int r;
 	struct cache *cache = ti->private;
 
 	if (argc != 2)
 		return -EINVAL;
 
-	r = process_config_option(cache, argv);
-	if (r == NOT_CORE_OPTION)
-		return policy_set_config_value(cache->policy, argv[0], argv[1]);
-
-	return r;
+	return set_config_value(cache, argv[0], argv[1]);
 }
 
 static int cache_iterate_devices(struct dm_target *ti,
@@ -2612,7 +2615,7 @@ static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
 
 static struct target_type cache_target = {
 	.name = "cache",
-	.version = {1, 1, 0},
+	.version = {1, 1, 1},
 	.module = THIS_MODULE,
 	.ctr = cache_ctr,
 	.dtr = cache_dtr,