[PATCH 08/32] target: Convert tg_pt_gp_ref_cnt to kref

[Andy Grover <agrover@xxxxxxxxxx>]

Use kref to handle reference counting.

Signed-off-by: Andy Grover <agrover@xxxxxxxxxx>
---
 drivers/target/target_core_alua.c |   39 +++++++++++++++++-------------------
 include/target/target_core_base.h |    2 +-
 2 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
index fe2eada..ba7b3d6 100644
--- a/drivers/target/target_core_alua.c
+++ b/drivers/target/target_core_alua.c
@@ -74,6 +74,16 @@ static void release_alua_lu_gp_mem(struct kref *ref)
 #define get_alua_lu_gp_mem(x) kref_get(&x->refcount)
 #define put_alua_lu_gp_mem(x) kref_put(&x->refcount, release_alua_lu_gp_mem)
 
+static void release_alua_tg_pt_gp(struct kref *ref)
+{
+	struct t10_alua_tg_pt_gp *tg_pt_gp = container_of(ref, struct t10_alua_tg_pt_gp, refcount);
+
+	kmem_cache_free(t10_alua_tg_pt_gp_cache, tg_pt_gp);
+}
+
+#define get_alua_tg_pt_gp(x) kref_get(&x->refcount)
+#define put_alua_tg_pt_gp(x) kref_put(&x->refcount, release_alua_tg_pt_gp)
+
 /*
  * REPORT_TARGET_PORT_GROUPS
  *
@@ -327,8 +337,7 @@ target_emulate_set_target_port_groups(struct se_cmd *cmd)
 				if (tg_pt_id != tg_pt_gp->tg_pt_gp_id)
 					continue;
 
-				atomic_inc(&tg_pt_gp->tg_pt_gp_ref_cnt);
-				smp_mb__after_atomic_inc();
+				get_alua_tg_pt_gp(tg_pt_gp);
 
 				spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
 
@@ -338,8 +347,7 @@ target_emulate_set_target_port_groups(struct se_cmd *cmd)
 					found = true;
 
 				spin_lock(&dev->t10_alua.tg_pt_gps_lock);
-				atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
-				smp_mb__after_atomic_dec();
+				put_alua_tg_pt_gp(tg_pt_gp);
 				break;
 			}
 			spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
@@ -975,8 +983,7 @@ int core_alua_do_port_transition(
 				port = NULL;
 				nacl = NULL;
 			}
-			atomic_inc(&tg_pt_gp->tg_pt_gp_ref_cnt);
-			smp_mb__after_atomic_inc();
+			get_alua_tg_pt_gp(tg_pt_gp);
 			spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
 			/*
 			 * core_alua_do_transition_tg_pt() will always return
@@ -986,8 +993,7 @@ int core_alua_do_port_transition(
 					nacl, md_buf, new_state, explicit);
 
 			spin_lock(&dev->t10_alua.tg_pt_gps_lock);
-			atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
-			smp_mb__after_atomic_dec();
+			put_alua_tg_pt_gp(tg_pt_gp);
 		}
 		spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
 
@@ -1354,7 +1360,7 @@ struct t10_alua_tg_pt_gp *core_alua_allocate_tg_pt_gp(struct se_device *dev,
 	INIT_LIST_HEAD(&tg_pt_gp->tg_pt_gp_mem_list);
 	mutex_init(&tg_pt_gp->tg_pt_gp_md_mutex);
 	spin_lock_init(&tg_pt_gp->tg_pt_gp_lock);
-	atomic_set(&tg_pt_gp->tg_pt_gp_ref_cnt, 0);
+	kref_init(&tg_pt_gp->refcount);
 	tg_pt_gp->tg_pt_gp_dev = dev;
 	tg_pt_gp->tg_pt_gp_md_buf_len = ALUA_MD_BUF_LEN;
 	atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state,
@@ -1485,15 +1491,6 @@ void core_alua_free_tg_pt_gp(
 	spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
 
 	/*
-	 * Allow a struct t10_alua_tg_pt_gp_member * referenced by
-	 * core_alua_get_tg_pt_gp_by_name() in
-	 * target_core_configfs.c:target_core_store_alua_tg_pt_gp()
-	 * to be released with core_alua_put_tg_pt_gp_from_name().
-	 */
-	while (atomic_read(&tg_pt_gp->tg_pt_gp_ref_cnt))
-		cpu_relax();
-
-	/*
 	 * Release reference to struct t10_alua_tg_pt_gp from all associated
 	 * struct se_port.
 	 */
@@ -1527,7 +1524,7 @@ void core_alua_free_tg_pt_gp(
 	}
 	spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
 
-	kmem_cache_free(t10_alua_tg_pt_gp_cache, tg_pt_gp);
+	put_alua_tg_pt_gp(tg_pt_gp);
 }
 
 void core_alua_free_tg_pt_gp_mem(struct se_port *port)
@@ -1572,7 +1569,7 @@ static struct t10_alua_tg_pt_gp *core_alua_get_tg_pt_gp_by_name(
 			continue;
 		ci = &tg_pt_gp->tg_pt_gp_group.cg_item;
 		if (!strcmp(config_item_name(ci), name)) {
-			atomic_inc(&tg_pt_gp->tg_pt_gp_ref_cnt);
+			get_alua_tg_pt_gp(tg_pt_gp);
 			spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
 			return tg_pt_gp;
 		}
@@ -1588,7 +1585,7 @@ static void core_alua_put_tg_pt_gp_from_name(
 	struct se_device *dev = tg_pt_gp->tg_pt_gp_dev;
 
 	spin_lock(&dev->t10_alua.tg_pt_gps_lock);
-	atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
+	put_alua_tg_pt_gp(tg_pt_gp);
 	spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
 }
 
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 2d56eaf..58b04f9 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -296,7 +296,7 @@ struct t10_alua_tg_pt_gp {
 	u32	tg_pt_gp_md_buf_len;
 	u32	tg_pt_gp_members;
 	atomic_t tg_pt_gp_alua_access_state;
-	atomic_t tg_pt_gp_ref_cnt;
+	struct kref refcount;
 	spinlock_t tg_pt_gp_lock;
 	struct mutex tg_pt_gp_md_mutex;
 	struct se_device *tg_pt_gp_dev;
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html