[PATCH 04/11] nvmet-fcloop: track ref counts for nports

[Daniel Wagner <wagi@kernel.org>]

A nport object is always used in association with targerport,
remoteport, tport and rport objects. Add explicit references for any of
the associated object. This makes the unreliable reference updates in
the two callback fcloop_targetport_delete and fcloop_remoteport_delete
obsolete.

Signed-off-by: Daniel Wagner <wagi@kernel.org>
---
 drivers/nvme/target/fcloop.c | 57 +++++++++++++++++++++++++++++++++++---------
 1 file changed, 46 insertions(+), 11 deletions(-)

diff --git a/drivers/nvme/target/fcloop.c b/drivers/nvme/target/fcloop.c
index de1963c34bd88d0335f70de569565740fd395a0a..80693705c069dd114b2d4f15d0482dd2d713a273 100644
--- a/drivers/nvme/target/fcloop.c
+++ b/drivers/nvme/target/fcloop.c
@@ -1071,16 +1071,11 @@ fcloop_remoteport_delete(struct nvme_fc_remote_port *remoteport)
 	struct fcloop_rport *rport = remoteport->private;
 
 	flush_work(&rport->ls_work);
-	fcloop_nport_put(rport->nport);
 }
 
 static void
 fcloop_targetport_delete(struct nvmet_fc_target_port *targetport)
 {
-	struct fcloop_tport *tport = targetport->private;
-
-	flush_work(&tport->ls_work);
-	fcloop_nport_put(tport->nport);
 }
 
 #define	FCLOOP_HW_QUEUES		4
@@ -1358,6 +1353,7 @@ fcloop_create_remote_port(struct device *dev, struct device_attribute *attr,
 	struct nvme_fc_port_info pinfo;
 	int ret;
 
+	/* nport ref get: rport */
 	nport = fcloop_alloc_nport(buf, count, true);
 	if (!nport)
 		return -EIO;
@@ -1375,6 +1371,9 @@ fcloop_create_remote_port(struct device *dev, struct device_attribute *attr,
 		return ret;
 	}
 
+	/* nport ref get: remoteport */
+	fcloop_nport_get(nport);
+
 	/* success */
 	rport = remoteport->private;
 	rport->remoteport = remoteport;
@@ -1403,16 +1402,27 @@ __unlink_remote_port(struct fcloop_nport *nport)
 		nport->tport->remoteport = NULL;
 	nport->rport = NULL;
 
+	/* nport ref put: rport */
+	fcloop_nport_put(nport);
+
 	return rport;
 }
 
 static int
 __remoteport_unreg(struct fcloop_nport *nport, struct fcloop_rport *rport)
 {
-	if (!rport)
-		return -EALREADY;
+	int ret;
 
-	return nvme_fc_unregister_remoteport(rport->remoteport);
+	if (!rport) {
+		ret = -EALREADY;
+		goto out;
+	}
+
+	ret = nvme_fc_unregister_remoteport(rport->remoteport);
+out:
+	/* nport ref put: remoteport */
+	fcloop_nport_put(nport);
+	return ret;
 }
 
 static ssize_t
@@ -1434,6 +1444,9 @@ fcloop_delete_remote_port(struct device *dev, struct device_attribute *attr,
 	list_for_each_entry(tmpport, &fcloop_nports, nport_list) {
 		if (tmpport->node_name == nodename &&
 		    tmpport->port_name == portname && tmpport->rport) {
+
+			if (!fcloop_nport_get(tmpport))
+				break;
 			nport = tmpport;
 			rport = __unlink_remote_port(nport);
 			break;
@@ -1447,6 +1460,8 @@ fcloop_delete_remote_port(struct device *dev, struct device_attribute *attr,
 
 	ret = __remoteport_unreg(nport, rport);
 
+	fcloop_nport_put(nport);
+
 	return ret ? ret : count;
 }
 
@@ -1460,6 +1475,7 @@ fcloop_create_target_port(struct device *dev, struct device_attribute *attr,
 	struct nvmet_fc_port_info tinfo;
 	int ret;
 
+	/* nport ref get: tport */
 	nport = fcloop_alloc_nport(buf, count, false);
 	if (!nport)
 		return -EIO;
@@ -1475,6 +1491,9 @@ fcloop_create_target_port(struct device *dev, struct device_attribute *attr,
 		return ret;
 	}
 
+	/* nport ref get: targetport */
+	fcloop_nport_get(nport);
+
 	/* success */
 	tport = targetport->private;
 	tport->targetport = targetport;
@@ -1501,16 +1520,27 @@ __unlink_target_port(struct fcloop_nport *nport)
 		nport->rport->targetport = NULL;
 	nport->tport = NULL;
 
+	/* nport ref put: tport */
+	fcloop_nport_put(nport);
+
 	return tport;
 }
 
 static int
 __targetport_unreg(struct fcloop_nport *nport, struct fcloop_tport *tport)
 {
-	if (!tport)
-		return -EALREADY;
+	int ret;
 
-	return nvmet_fc_unregister_targetport(tport->targetport);
+	if (!tport) {
+		ret = -EALREADY;
+		goto out;
+	}
+
+	ret = nvmet_fc_unregister_targetport(tport->targetport);
+out:
+	/* nport ref put: targetport */
+	fcloop_nport_put(nport);
+	return ret;
 }
 
 static ssize_t
@@ -1532,6 +1562,9 @@ fcloop_delete_target_port(struct device *dev, struct device_attribute *attr,
 	list_for_each_entry(tmpport, &fcloop_nports, nport_list) {
 		if (tmpport->node_name == nodename &&
 		    tmpport->port_name == portname && tmpport->tport) {
+
+			if (!fcloop_nport_get(tmpport))
+				break;
 			nport = tmpport;
 			tport = __unlink_target_port(nport);
 			break;
@@ -1545,6 +1578,8 @@ fcloop_delete_target_port(struct device *dev, struct device_attribute *attr,
 
 	ret = __targetport_unreg(nport, tport);
 
+	fcloop_nport_put(nport);
+
 	return ret ? ret : count;
 }
 

-- 
2.48.1