LU-16796 ptlrpc: Change struct ls_device to use kref

This patch changes struct ls_device to use
kref(refcount_t) instead of atomic_t

Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: Iba3965ef884ef65ab2d379ed389dfbea4ef8a453
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/51811
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>

diff --git a/lustre/obdclass/llog_osd.c b/lustre/obdclass/llog_osd.c
index 3b36294..c60d4c0 100644 (file)
--- a/lustre/obdclass/llog_osd.c
+++ b/lustre/obdclass/llog_osd.c
@@ -1307,7 +1307,7 @@ static int llog_osd_open(const struct lu_env *env, struct llog_handle *handle,
                goto after_open;
        }
 
-       ls = ls_device_get(dt);
+       ls = ls_device_find_or_init(dt);
        if (IS_ERR(ls))
                RETURN(PTR_ERR(ls));
 

diff --git a/lustre/obdclass/local_storage.c b/lustre/obdclass/local_storage.c
index 6015d1d..1a9d08b 100644 (file)
--- a/lustre/obdclass/local_storage.c
+++ b/lustre/obdclass/local_storage.c
@@ -105,20 +105,6 @@ static const struct lu_device_operations ls_lu_dev_ops = {
        .ldo_object_alloc =     ls_object_alloc
 };
 
-static struct ls_device *__ls_find_dev(struct dt_device *dev)
-{
-       struct ls_device *ls, *ret = NULL;
-
-       list_for_each_entry(ls, &ls_list_head, ls_linkage) {
-               if (ls->ls_osd == dev) {
-                       atomic_inc(&ls->ls_refcount);
-                       ret = ls;
-                       break;
-               }
-       }
-       return ret;
-}
-
 static const struct lu_device_type_operations ls_device_type_ops = {
        .ldto_start = NULL,
        .ldto_stop  = NULL,
@@ -129,23 +115,18 @@ static struct lu_device_type ls_lu_type = {
        .ldt_ops  = &ls_device_type_ops,
 };
 
-struct ls_device *ls_device_get(struct dt_device *dev)
+static
+struct ls_device *ls_device_init(struct dt_device *dev)
 {
        struct ls_device *ls;
 
        ENTRY;
 
-       mutex_lock(&ls_list_mutex);
-       ls = __ls_find_dev(dev);
-       if (ls)
-               GOTO(out_ls, ls);
-
-       /* not found, then create */
        OBD_ALLOC_PTR(ls);
        if (ls == NULL)
                GOTO(out_ls, ls = ERR_PTR(-ENOMEM));
 
-       atomic_set(&ls->ls_refcount, 1);
+       kref_init(&ls->ls_refcount);
        INIT_LIST_HEAD(&ls->ls_los_list);
        mutex_init(&ls->ls_los_mutex);
 
@@ -159,25 +140,54 @@ struct ls_device *ls_device_get(struct dt_device *dev)
        /* finally add ls to the list */
        list_add(&ls->ls_linkage, &ls_list_head);
 out_ls:
+       RETURN(ls);
+}
+
+struct ls_device *ls_device_find_or_init(struct dt_device *dev)
+{
+       struct ls_device *ls, *ret = NULL;
+
+       ENTRY;
+
+       mutex_lock(&ls_list_mutex);
+       /* find */
+       list_for_each_entry(ls, &ls_list_head, ls_linkage) {
+               if (ls->ls_osd == dev) {
+                       kref_get(&ls->ls_refcount);
+                       ret = ls;
+                       break;
+               }
+       }
+       /* found */
+       if (ret)
+               GOTO(out_ls, ret);
+
+       /* not found, then create */
+       ls = ls_device_init(dev);
+out_ls:
        mutex_unlock(&ls_list_mutex);
        RETURN(ls);
 }
 
+static void ls_device_put_free(struct kref *kref)
+{
+       struct ls_device *ls = container_of(kref, struct ls_device,
+                                           ls_refcount);
+
+       LASSERT(list_empty(&ls->ls_los_list));
+       list_del(&ls->ls_linkage);
+       mutex_unlock(&ls_list_mutex);
+}
+
 void ls_device_put(const struct lu_env *env, struct ls_device *ls)
 {
        LASSERT(env);
-       if (!atomic_dec_and_test(&ls->ls_refcount))
-               return;
-
-       mutex_lock(&ls_list_mutex);
-       if (atomic_read(&ls->ls_refcount) == 0) {
-               LASSERT(list_empty(&ls->ls_los_list));
-               list_del(&ls->ls_linkage);
+       if (kref_put_mutex(&ls->ls_refcount, ls_device_put_free,
+                          &ls_list_mutex)) {
                lu_site_purge(env, ls->ls_top_dev.dd_lu_dev.ld_site, ~0);
                lu_device_fini(&ls->ls_top_dev.dd_lu_dev);
                OBD_FREE_PTR(ls);
        }
-       mutex_unlock(&ls_list_mutex);
 }
 
 /**
@@ -490,7 +500,7 @@ struct dt_object *local_file_find_or_create_with_fid(const struct lu_env *env,
        } else {
                struct ls_device *ls;
 
-               ls = ls_device_get(dt);
+               ls = ls_device_find_or_init(dt);
                if (IS_ERR(ls)) {
                        dto = ERR_CAST(ls);
                } else {
@@ -585,7 +595,7 @@ local_index_find_or_create_with_fid(const struct lu_env *env,
        } else {
                struct ls_device *ls;
 
-               ls = ls_device_get(dt);
+               ls = ls_device_find_or_init(dt);
                if (IS_ERR(ls)) {
                        dto = ERR_CAST(ls);
                } else {
@@ -799,6 +809,7 @@ static int lastid_compat_check(const struct lu_env *env, struct dt_device *dev,
        return rc;
 }
 
+
 /**
  * Initialize local OID storage for required sequence.
  * That may be needed for services that uses local files and requires
@@ -830,7 +841,7 @@ int local_oid_storage_init(const struct lu_env *env, struct dt_device *dev,
 
        ENTRY;
 
-       ls = ls_device_get(dev);
+       ls = ls_device_find_or_init(dev);
        if (IS_ERR(ls))
                RETURN(PTR_ERR(ls));
 
@@ -847,7 +858,7 @@ int local_oid_storage_init(const struct lu_env *env, struct dt_device *dev,
        atomic_set(&(*los)->los_refcount, 1);
        mutex_init(&(*los)->los_id_lock);
        (*los)->los_dev = &ls->ls_top_dev;
-       atomic_inc(&ls->ls_refcount);
+       kref_get(&ls->ls_refcount);
        list_add(&(*los)->los_list, &ls->ls_los_list);
 
        /* Use {seq, 0, 0} to create the LAST_ID file for every
@@ -926,7 +937,7 @@ out_trans:
 out_los:
        if (rc != 0) {
                list_del(&(*los)->los_list);
-               atomic_dec(&ls->ls_refcount);
+               ls_device_put(env, ls);
                OBD_FREE_PTR(*los);
                *los = NULL;
                if (o != NULL && !IS_ERR(o))

diff --git a/lustre/obdclass/local_storage.h b/lustre/obdclass/local_storage.h
index 63af194..2353650 100644 (file)
--- a/lustre/obdclass/local_storage.h
+++ b/lustre/obdclass/local_storage.h
@@ -42,7 +42,7 @@ struct ls_device {
        /* all initialized ls_devices on this node linked by this */
        struct list_head         ls_linkage;
        /* how many handle's reference this local storage */
-       atomic_t                 ls_refcount;
+       struct kref              ls_refcount;
        /* underlaying OSD device */
        struct dt_device        *ls_osd;
        /* list of all local OID storages */
@@ -74,7 +74,7 @@ static inline struct dt_object *ls_locate(const struct lu_env *env,
                            &ls->ls_top_dev.dd_lu_dev, conf);
 }
 
-struct ls_device *ls_device_get(struct dt_device *dev);
+struct ls_device *ls_device_find_or_init(struct dt_device *dev);
 void ls_device_put(const struct lu_env *env, struct ls_device *ls);
 struct local_oid_storage *dt_los_find(struct ls_device *ls, __u64 seq);
 void dt_los_put(struct local_oid_storage *los);