[PATCH v3 03/17] scsi: iscsi: stop queueing during ep_disconnect

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During ep_disconnect we have been doing iscsi_suspend_tx/queue to block
new IO but every driver except cxgbi and iscsi_tcp can still get IO from
__iscsi_conn_send_pdu if we haven't called iscsi_conn_failure before
ep_disconnect. This could happen if we were terminating the session, and
the logout timedout before it was even sent to libiscsi.

This patch fixes the issue by adding a helper which reverses the bind_conn
call that allows new IO to be queued. Drivers implementing ep_disconnect
can use this to make sure new IO is not queued to them when handling the
disconnect.

Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
---
 drivers/infiniband/ulp/iser/iscsi_iser.c |  1 +
 drivers/scsi/be2iscsi/be_main.c          |  1 +
 drivers/scsi/bnx2i/bnx2i_iscsi.c         |  1 +
 drivers/scsi/cxgbi/cxgb3i/cxgb3i.c       |  1 +
 drivers/scsi/cxgbi/cxgb4i/cxgb4i.c       |  1 +
 drivers/scsi/libiscsi.c                  | 61 +++++++++++++++++++++---
 drivers/scsi/qedi/qedi_iscsi.c           |  1 +
 drivers/scsi/qla4xxx/ql4_os.c            |  1 +
 drivers/scsi/scsi_transport_iscsi.c      |  3 ++
 include/scsi/libiscsi.h                  |  1 +
 include/scsi/scsi_transport_iscsi.h      |  1 +
 11 files changed, 67 insertions(+), 6 deletions(-)

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index 8fcaa1136f2c..6baebcb6d14d 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -1002,6 +1002,7 @@ static struct iscsi_transport iscsi_iser_transport = {
 	/* connection management */
 	.create_conn            = iscsi_iser_conn_create,
 	.bind_conn              = iscsi_iser_conn_bind,
+	.unbind_conn		= iscsi_conn_unbind,
 	.destroy_conn           = iscsi_conn_teardown,
 	.attr_is_visible	= iser_attr_is_visible,
 	.set_param              = iscsi_iser_set_param,
diff --git a/drivers/scsi/be2iscsi/be_main.c b/drivers/scsi/be2iscsi/be_main.c
index 90fcddb76f46..e9658a67d9da 100644
--- a/drivers/scsi/be2iscsi/be_main.c
+++ b/drivers/scsi/be2iscsi/be_main.c
@@ -5809,6 +5809,7 @@ struct iscsi_transport beiscsi_iscsi_transport = {
 	.destroy_session = beiscsi_session_destroy,
 	.create_conn = beiscsi_conn_create,
 	.bind_conn = beiscsi_conn_bind,
+	.unbind_conn = iscsi_conn_unbind,
 	.destroy_conn = iscsi_conn_teardown,
 	.attr_is_visible = beiscsi_attr_is_visible,
 	.set_iface_param = beiscsi_iface_set_param,
diff --git a/drivers/scsi/bnx2i/bnx2i_iscsi.c b/drivers/scsi/bnx2i/bnx2i_iscsi.c
index 1e6d8f62ea3c..b6c1da46d582 100644
--- a/drivers/scsi/bnx2i/bnx2i_iscsi.c
+++ b/drivers/scsi/bnx2i/bnx2i_iscsi.c
@@ -2276,6 +2276,7 @@ struct iscsi_transport bnx2i_iscsi_transport = {
 	.destroy_session	= bnx2i_session_destroy,
 	.create_conn		= bnx2i_conn_create,
 	.bind_conn		= bnx2i_conn_bind,
+	.unbind_conn		= iscsi_conn_unbind,
 	.destroy_conn		= bnx2i_conn_destroy,
 	.attr_is_visible	= bnx2i_attr_is_visible,
 	.set_param		= iscsi_set_param,
diff --git a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
index 37d99357120f..edcd3fab6973 100644
--- a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
+++ b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
@@ -117,6 +117,7 @@ static struct iscsi_transport cxgb3i_iscsi_transport = {
 	/* connection management */
 	.create_conn	= cxgbi_create_conn,
 	.bind_conn	= cxgbi_bind_conn,
+	.unbind_conn	= iscsi_conn_unbind,
 	.destroy_conn	= iscsi_tcp_conn_teardown,
 	.start_conn	= iscsi_conn_start,
 	.stop_conn	= iscsi_conn_stop,
diff --git a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
index 2c3491528d42..efb3e2b3398e 100644
--- a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
+++ b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
@@ -134,6 +134,7 @@ static struct iscsi_transport cxgb4i_iscsi_transport = {
 	/* connection management */
 	.create_conn	= cxgbi_create_conn,
 	.bind_conn		= cxgbi_bind_conn,
+	.unbind_conn	= iscsi_conn_unbind,
 	.destroy_conn	= iscsi_tcp_conn_teardown,
 	.start_conn		= iscsi_conn_start,
 	.stop_conn		= iscsi_conn_stop,
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index aa5ceaffc697..ce3898fdb10f 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1387,22 +1387,28 @@ void iscsi_session_failure(struct iscsi_session *session,
 }
 EXPORT_SYMBOL_GPL(iscsi_session_failure);
 
-void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
+static void iscsi_set_conn_failed(struct iscsi_conn *conn)
 {
 	struct iscsi_session *session = conn->session;
 
-	spin_lock_bh(&session->frwd_lock);
-	if (session->state == ISCSI_STATE_FAILED) {
-		spin_unlock_bh(&session->frwd_lock);
+	if (session->state == ISCSI_STATE_FAILED)
 		return;
-	}
 
 	if (conn->stop_stage == 0)
 		session->state = ISCSI_STATE_FAILED;
-	spin_unlock_bh(&session->frwd_lock);
 
 	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
 	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
+}
+
+void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
+{
+	struct iscsi_session *session = conn->session;
+
+	spin_lock_bh(&session->frwd_lock);
+	iscsi_set_conn_failed(conn);
+	spin_unlock_bh(&session->frwd_lock);
+
 	iscsi_conn_error_event(conn->cls_conn, err);
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_failure);
@@ -2220,6 +2226,49 @@ static void iscsi_check_transport_timeouts(struct timer_list *t)
 	spin_unlock(&session->frwd_lock);
 }
 
+/*
+ * iscsi_conn_unbind - prevent queueing to conn.
+ * @conn: iscsi conn ep is bound to.
+ *
+ * This must be called by drivers implementing the ep_disconnect callout.
+ * It disables queueing to the connection from libiscsi in preparation for
+ * an ep_disconnect call.
+ */
+void iscsi_conn_unbind(struct iscsi_cls_conn *cls_conn)
+{
+	struct iscsi_session *session;
+	struct iscsi_conn *conn;
+
+	if (!cls_conn)
+		return;
+
+	conn = cls_conn->dd_data;
+	session = conn->session;
+	/*
+	 * Wait for iscsi_eh calls to exit. We don't wait for the tmf to
+	 * complete or timeout. The caller just wants to know what's running
+	 * is everything that needs to be cleaned up, and no cmds will be
+	 * queued.
+	 */
+	mutex_lock(&session->eh_mutex);
+
+	iscsi_suspend_queue(conn);
+	iscsi_suspend_tx(conn);
+
+	spin_lock_bh(&session->frwd_lock);
+	/*
+	 * if logout timed out before userspace could even send a PDU the
+	 * state might still be in ISCSI_STATE_LOGGED_IN and allowing new cmds
+	 * and TMFs.
+	 */
+	if (session->state == ISCSI_STATE_LOGGED_IN)
+		iscsi_set_conn_failed(conn);
+
+	spin_unlock_bh(&session->frwd_lock);
+	mutex_unlock(&session->eh_mutex);
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_unbind);
+
 static void iscsi_prep_abort_task_pdu(struct iscsi_task *task,
 				      struct iscsi_tm *hdr)
 {
diff --git a/drivers/scsi/qedi/qedi_iscsi.c b/drivers/scsi/qedi/qedi_iscsi.c
index 08c05403cd72..ef16537c523c 100644
--- a/drivers/scsi/qedi/qedi_iscsi.c
+++ b/drivers/scsi/qedi/qedi_iscsi.c
@@ -1401,6 +1401,7 @@ struct iscsi_transport qedi_iscsi_transport = {
 	.destroy_session = qedi_session_destroy,
 	.create_conn = qedi_conn_create,
 	.bind_conn = qedi_conn_bind,
+	.unbind_conn = iscsi_conn_unbind,
 	.start_conn = qedi_conn_start,
 	.stop_conn = iscsi_conn_stop,
 	.destroy_conn = qedi_conn_destroy,
diff --git a/drivers/scsi/qla4xxx/ql4_os.c b/drivers/scsi/qla4xxx/ql4_os.c
index 7bd9a4a04ad5..ff663cb330c2 100644
--- a/drivers/scsi/qla4xxx/ql4_os.c
+++ b/drivers/scsi/qla4xxx/ql4_os.c
@@ -259,6 +259,7 @@ static struct iscsi_transport qla4xxx_iscsi_transport = {
 	.start_conn             = qla4xxx_conn_start,
 	.create_conn            = qla4xxx_conn_create,
 	.bind_conn              = qla4xxx_conn_bind,
+	.unbind_conn		= iscsi_conn_unbind,
 	.stop_conn              = iscsi_conn_stop,
 	.destroy_conn           = qla4xxx_conn_destroy,
 	.set_param              = iscsi_set_param,
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 441f0152193f..833114c8e197 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -2981,6 +2981,8 @@ static int iscsi_if_ep_disconnect(struct iscsi_transport *transport,
 		conn->ep = NULL;
 		mutex_unlock(&conn->ep_mutex);
 		conn->state = ISCSI_CONN_FAILED;
+
+		transport->unbind_conn(conn);
 	}
 
 	transport->ep_disconnect(ep);
@@ -4656,6 +4658,7 @@ iscsi_register_transport(struct iscsi_transport *tt)
 	int err;
 
 	BUG_ON(!tt);
+	WARN_ON(tt->ep_disconnect && !tt->unbind_conn);
 
 	priv = iscsi_if_transport_lookup(tt);
 	if (priv)
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 8c6d358a8abc..ec6d508e7a4a 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -431,6 +431,7 @@ extern int iscsi_conn_start(struct iscsi_cls_conn *);
 extern void iscsi_conn_stop(struct iscsi_cls_conn *, int);
 extern int iscsi_conn_bind(struct iscsi_cls_session *, struct iscsi_cls_conn *,
 			   int);
+extern void iscsi_conn_unbind(struct iscsi_cls_conn *cls_conn);
 extern void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err);
 extern void iscsi_session_failure(struct iscsi_session *session,
 				  enum iscsi_err err);
diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h
index fc5a39839b4b..afc61a23628d 100644
--- a/include/scsi/scsi_transport_iscsi.h
+++ b/include/scsi/scsi_transport_iscsi.h
@@ -82,6 +82,7 @@ struct iscsi_transport {
 	void (*destroy_session) (struct iscsi_cls_session *session);
 	struct iscsi_cls_conn *(*create_conn) (struct iscsi_cls_session *sess,
 				uint32_t cid);
+	void (*unbind_conn) (struct iscsi_cls_conn *conn);
 	int (*bind_conn) (struct iscsi_cls_session *session,
 			  struct iscsi_cls_conn *cls_conn,
 			  uint64_t transport_eph, int is_leading);
-- 
2.25.1




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