[v2,09/29] lustre: obd_type: discard obd_types linked list.
diff mbox series

Message ID 1558356671-29599-10-git-send-email-jsimmons@infradead.org
State New
Headers show
Series
  • More lustre patches
Related show

Commit Message

James Simmons May 20, 2019, 12:50 p.m. UTC
From: NeilBrown <neilb@suse.com>

As all obd_types are kobjects in the lustre_kset kset,
they are linked together in that kset and don't
need any extra linkage.

There are non-obd_type objects in lustre_kset, added by
class_setup_tunables(). These have a different ->ktype, so we are
careful to only return objects with the correct ->ktype.

As kset_find_obj() returns a counted reference, we need
to put that reference when done.

Signed-off-by: NeilBrown <neilb@suse.com>
---
 fs/lustre/include/obd.h     |  1 -
 fs/lustre/obdclass/genops.c | 42 ++++++++++++++++++++----------------------
 2 files changed, 20 insertions(+), 23 deletions(-)

Patch
diff mbox series

diff --git a/fs/lustre/include/obd.h b/fs/lustre/include/obd.h
index 6bf052a..4c58b91 100644
--- a/fs/lustre/include/obd.h
+++ b/fs/lustre/include/obd.h
@@ -99,7 +99,6 @@  struct obd_info {
 };
 
 struct obd_type {
-	struct list_head	 typ_chain;
 	struct obd_ops		*typ_dt_ops;
 	struct md_ops		*typ_md_ops;
 	struct dentry		*typ_debugfs_entry;
diff --git a/fs/lustre/obdclass/genops.c b/fs/lustre/obdclass/genops.c
index 7be779f..3f46298 100644
--- a/fs/lustre/obdclass/genops.c
+++ b/fs/lustre/obdclass/genops.c
@@ -42,8 +42,6 @@ 
 #include <lprocfs_status.h>
 #include <lustre_kernelcomm.h>
 
-static DEFINE_SPINLOCK(obd_types_lock);
-static LIST_HEAD(obd_types);
 DEFINE_RWLOCK(obd_dev_lock);
 static struct obd_device *obd_devs[MAX_OBD_DEVICES];
 
@@ -52,6 +50,7 @@ 
 EXPORT_SYMBOL(obdo_cachep);
 static struct kmem_cache *import_cachep;
 
+static struct kobj_type class_ktype;
 static struct workqueue_struct *zombie_wq;
 static void obd_zombie_export_add(struct obd_export *exp);
 static void obd_zombie_import_add(struct obd_import *imp);
@@ -88,23 +87,20 @@  static void obd_device_free(struct obd_device *obd)
 
 static struct obd_type *class_search_type(const char *name)
 {
-	struct obd_type *type;
+	struct kobject *kobj = kset_find_obj(lustre_kset, name);
 
-	spin_lock(&obd_types_lock);
-	list_for_each_entry(type, &obd_types, typ_chain) {
-		if (strcmp(type->typ_name, name) == 0) {
-			spin_unlock(&obd_types_lock);
-			return type;
-		}
-	}
-	spin_unlock(&obd_types_lock);
+	if (kobj && kobj->ktype == &class_ktype)
+		return container_of(kobj, struct obd_type, typ_kobj);
+
+	kobject_put(kobj);
 	return NULL;
 }
 
 static struct obd_type *class_get_type(const char *name)
 {
-	struct obd_type *type = class_search_type(name);
+	struct obd_type *type;
 
+	type = class_search_type(name);
 	if (!type) {
 		const char *modname = name;
 
@@ -121,6 +117,11 @@  static struct obd_type *class_get_type(const char *name)
 		type->typ_refcnt++;
 		try_module_get(type->typ_dt_ops->owner);
 		spin_unlock(&type->obd_type_lock);
+		/* class_search_type() returned a counted reference,
+		 * but we don't need that count any more as
+		 * we have one through typ_refcnt.
+		 */
+		kobject_put(&type->typ_kobj);
 	}
 	return type;
 }
@@ -140,10 +141,6 @@  static void class_sysfs_release(struct kobject *kobj)
 
 	debugfs_remove_recursive(type->typ_debugfs_entry);
 
-	spin_lock(&obd_types_lock);
-	list_del(&type->typ_chain);
-	spin_unlock(&obd_types_lock);
-
 	kfree(type->typ_md_ops);
 	kfree(type->typ_dt_ops);
 	kfree(type);
@@ -166,8 +163,10 @@  int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
 	/* sanity check */
 	LASSERT(strnlen(name, CLASS_MAX_NAME) < CLASS_MAX_NAME);
 
-	if (class_search_type(name)) {
+	type = class_search_type(name);
+	if (type) {
 		CDEBUG(D_IOCTL, "Type %s already registered\n", name);
+		kobject_put(&type->typ_kobj);
 		return -EEXIST;
 	}
 
@@ -175,7 +174,6 @@  int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
 	if (!type)
 		return -ENOMEM;
 
-	INIT_LIST_HEAD(&type->typ_chain);
 	type->typ_kobj.kset = lustre_kset;
 	rc = kobject_init_and_add(&type->typ_kobj, &class_ktype,
 				  &lustre_kset->kobj, "%s", name);
@@ -204,10 +202,6 @@  int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
 			goto failed;
 	}
 
-	spin_lock(&obd_types_lock);
-	list_add(&type->typ_chain, &obd_types);
-	spin_unlock(&obd_types_lock);
-
 	return 0;
 
 failed:
@@ -232,12 +226,16 @@  int class_unregister_type(const char *name)
 		/* Remove ops, but leave the name for debugging */
 		kfree(type->typ_dt_ops);
 		kfree(type->typ_md_ops);
+		kobject_put(&type->typ_kobj);
 		return -EBUSY;
 	}
 
 	if (type->typ_lu)
 		lu_device_type_fini(type->typ_lu);
 
+	/* Put the ref returned by class_search_type() */
+	kobject_put(&type->typ_kobj);
+	/* Put the final ref */
 	kobject_put(&type->typ_kobj);
 
 	return 0;