[lustre-devel] [PATCH 06/37] lustre: obd_type: discard obd_types linked list.
James Simmons
jsimmons at infradead.org
Sun Feb 24 09:00:58 PST 2019
> 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.
>
> As kset_find_obj() returns a counted reference, we need
> to put that reference when done.
>
> Signed-off-by: NeilBrown <neilb at suse.com>
> ---
> drivers/staging/lustre/lustre/include/obd.h | 1 -
> drivers/staging/lustre/lustre/obdclass/genops.c | 41 +++++++++++------------
> 2 files changed, 19 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/staging/lustre/lustre/include/obd.h b/drivers/staging/lustre/lustre/include/obd.h
> index 3aa9cc889949..50f33f400075 100644
> --- a/drivers/staging/lustre/lustre/include/obd.h
> +++ b/drivers/staging/lustre/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/drivers/staging/lustre/lustre/obdclass/genops.c b/drivers/staging/lustre/lustre/obdclass/genops.c
> index 32581f1a92ac..775e4fa4f6a8 100644
> --- a/drivers/staging/lustre/lustre/obdclass/genops.c
> +++ b/drivers/staging/lustre/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];
>
> @@ -88,22 +86,19 @@ 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);
> +
> + if (kobj)
> + return container_of(kobj, struct obd_type, typ_kobj);
>
> - 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);
> 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 +116,11 @@ 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;
> }
> @@ -143,10 +143,6 @@ static void class_sysfs_release(struct kobject *kobj)
> if (type->typ_lu)
> lu_device_type_fini(type->typ_lu);
>
> - 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);
> @@ -169,8 +165,10 @@ 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;
> }
>
> @@ -181,7 +179,6 @@ int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
>
> type->typ_kobj.kset = lustre_kset;
> kobject_init(&type->typ_kobj, &class_ktype);
> - INIT_LIST_HEAD(&type->typ_chain);
>
> type->typ_dt_ops = kzalloc(sizeof(*type->typ_dt_ops), GFP_NOFS);
> type->typ_md_ops = kzalloc(sizeof(*type->typ_md_ops), GFP_NOFS);
> @@ -210,10 +207,6 @@ 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:
> @@ -238,9 +231,13 @@ 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;
> }
>
> + /* Put the ref returned by class_search_type() */
> + kobject_put(&type->typ_kobj);
> + /* Put the final ref */
> kobject_put(&type->typ_kobj);
This last part needs to be kobject_del(&type->typ_kobj); but that
will be handled in the early patch.
> return 0;
>
>
>
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