dm-mpath: make dm_unregister_path_selector return void

dm_unregister_path_selector may only return error if there's a bug in the
code - so we make it return void and print a warning if the user abuses
this function to unregister a target that was not registered.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

Author: Mikulas Patocka

drivers/md/dm-path-selector.c

@@ -117,24 +117,22 @@ int dm_register_path_selector(struct path_selector_type *pst)
 }
 EXPORT_SYMBOL_GPL(dm_register_path_selector);
 
-int dm_unregister_path_selector(struct path_selector_type *pst)
+void dm_unregister_path_selector(struct path_selector_type *pst)
 {
 	struct ps_internal *psi;
 
 	down_write(&_ps_lock);
 
 	psi = __find_path_selector_type(pst->name);
-	if (!psi) {
+	if (WARN_ON(!psi)) {
 		up_write(&_ps_lock);
-		return -EINVAL;
+		return;
 	}
 
 	list_del(&psi->list);
 
 	up_write(&_ps_lock);
 
 	kfree(psi);
-
-	return 0;
 }
 EXPORT_SYMBOL_GPL(dm_unregister_path_selector);

drivers/md/dm-path-selector.h

@@ -96,7 +96,7 @@ struct path_selector_type {
 int dm_register_path_selector(struct path_selector_type *type);
 
 /* Unregister a path selector */
-int dm_unregister_path_selector(struct path_selector_type *type);
+void dm_unregister_path_selector(struct path_selector_type *type);
 
 /* Returns a registered path selector type */
 struct path_selector_type *dm_get_path_selector(const char *name);

drivers/md/dm-ps-historical-service-time.c

@@ -551,10 +551,7 @@ static int __init dm_hst_init(void)
 
 static void __exit dm_hst_exit(void)
 {
-	int r = dm_unregister_path_selector(&hst_ps);
-
-	if (r < 0)
-		DMERR("unregister failed %d", r);
+	dm_unregister_path_selector(&hst_ps);
 }
 
 module_init(dm_hst_init);

drivers/md/dm-ps-io-affinity.c

@@ -260,10 +260,7 @@ static int __init dm_ioa_init(void)
 
 static void __exit dm_ioa_exit(void)
 {
-	int ret = dm_unregister_path_selector(&ioa_ps);
-
-	if (ret < 0)
-		DMERR("unregister failed %d", ret);
+	dm_unregister_path_selector(&ioa_ps);
 }
 
 module_init(dm_ioa_init);

drivers/md/dm-ps-queue-length.c

@@ -270,10 +270,7 @@ static int __init dm_ql_init(void)
 
 static void __exit dm_ql_exit(void)
 {
-	int r = dm_unregister_path_selector(&ql_ps);
-
-	if (r < 0)
-		DMERR("unregister failed %d", r);
+	dm_unregister_path_selector(&ql_ps);
 }
 
 module_init(dm_ql_init);

drivers/md/dm-ps-round-robin.c

@@ -230,10 +230,7 @@ static int __init dm_rr_init(void)
 
 static void __exit dm_rr_exit(void)
 {
-	int r = dm_unregister_path_selector(&rr_ps);
-
-	if (r < 0)
-		DMERR("unregister failed %d", r);
+	dm_unregister_path_selector(&rr_ps);
 }
 
 module_init(dm_rr_init);

drivers/md/dm-ps-service-time.c

@@ -351,10 +351,7 @@ static int __init dm_st_init(void)
 
 static void __exit dm_st_exit(void)
 {
-	int r = dm_unregister_path_selector(&st_ps);
-
-	if (r < 0)
-		DMERR("unregister failed %d", r);
+	dm_unregister_path_selector(&st_ps);
 }
 
 module_init(dm_st_init);