linux-kernel - [PATCH AUTOSEL 5.17 23/34] scsi: iscsi: Fix offload conn cleanup when iscsid restarts

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Date:   Tue, 19 Apr 2022 14:10:50 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Mike Christie <michael.christie@...cle.com>,
        Manish Rangankar <mrangankar@...vell.com>,
        Lee Duncan <lduncan@...e.com>, Chris Leech <cleech@...hat.com>,
        "Martin K . Petersen" <martin.petersen@...cle.com>,
        Sasha Levin <sashal@...nel.org>, jejb@...ux.ibm.com,
        open-iscsi@...glegroups.com, linux-scsi@...r.kernel.org
Subject: [PATCH AUTOSEL 5.17 23/34] scsi: iscsi: Fix offload conn cleanup when iscsid restarts

From: Mike Christie <michael.christie@...cle.com>

[ Upstream commit cbd2283aaf47fef4ded4b29124b1ef3beb515f3a ]

When userspace restarts during boot or upgrades it won't know about the
offload driver's endpoint and connection mappings. iscsid will start by
cleaning up the old session by doing a stop_conn call. Later, if we are
able to create a new connection, we clean up the old endpoint during the
binding stage. The problem is that if we do stop_conn before doing the
ep_disconnect call offload, drivers can still be executing I/O. We then
might free tasks from the under the card/driver.

This moves the ep_disconnect call to before we do the stop_conn call for
this case. It will then work and look like a normal recovery/cleanup
procedure from the driver's point of view.

Link: https://lore.kernel.org/r/20220408001314.5014-3-michael.christie@oracle.com
Tested-by: Manish Rangankar <mrangankar@...vell.com>
Reviewed-by: Lee Duncan <lduncan@...e.com>
Reviewed-by: Chris Leech <cleech@...hat.com>
Signed-off-by: Mike Christie <michael.christie@...cle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/scsi/scsi_transport_iscsi.c | 48 +++++++++++++++++------------
 1 file changed, 28 insertions(+), 20 deletions(-)

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 126f6f23bffa..03cda2da80ef 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -2255,6 +2255,23 @@ static void iscsi_ep_disconnect(struct iscsi_cls_conn *conn, bool is_active)
 	ISCSI_DBG_TRANS_CONN(conn, "disconnect ep done.\n");
 }
 
+static void iscsi_if_disconnect_bound_ep(struct iscsi_cls_conn *conn,
+					 struct iscsi_endpoint *ep,
+					 bool is_active)
+{
+	/* Check if this was a conn error and the kernel took ownership */
+	if (!test_bit(ISCSI_CLS_CONN_BIT_CLEANUP, &conn->flags)) {
+		iscsi_ep_disconnect(conn, is_active);
+	} else {
+		ISCSI_DBG_TRANS_CONN(conn, "flush kernel conn cleanup.\n");
+		mutex_unlock(&conn->ep_mutex);
+
+		flush_work(&conn->cleanup_work);
+
+		mutex_lock(&conn->ep_mutex);
+	}
+}
+
 static int iscsi_if_stop_conn(struct iscsi_transport *transport,
 			      struct iscsi_uevent *ev)
 {
@@ -2275,6 +2292,16 @@ static int iscsi_if_stop_conn(struct iscsi_transport *transport,
 		cancel_work_sync(&conn->cleanup_work);
 		iscsi_stop_conn(conn, flag);
 	} else {
+		/*
+		 * For offload, when iscsid is restarted it won't know about
+		 * existing endpoints so it can't do a ep_disconnect. We clean
+		 * it up here for userspace.
+		 */
+		mutex_lock(&conn->ep_mutex);
+		if (conn->ep)
+			iscsi_if_disconnect_bound_ep(conn, conn->ep, true);
+		mutex_unlock(&conn->ep_mutex);
+
 		/*
 		 * Figure out if it was the kernel or userspace initiating this.
 		 */
@@ -3003,16 +3030,7 @@ static int iscsi_if_ep_disconnect(struct iscsi_transport *transport,
 	}
 
 	mutex_lock(&conn->ep_mutex);
-	/* Check if this was a conn error and the kernel took ownership */
-	if (test_bit(ISCSI_CLS_CONN_BIT_CLEANUP, &conn->flags)) {
-		ISCSI_DBG_TRANS_CONN(conn, "flush kernel conn cleanup.\n");
-		mutex_unlock(&conn->ep_mutex);
-
-		flush_work(&conn->cleanup_work);
-		goto put_ep;
-	}
-
-	iscsi_ep_disconnect(conn, false);
+	iscsi_if_disconnect_bound_ep(conn, ep, false);
 	mutex_unlock(&conn->ep_mutex);
 put_ep:
 	iscsi_put_endpoint(ep);
@@ -3723,16 +3741,6 @@ static int iscsi_if_transport_conn(struct iscsi_transport *transport,
 
 	switch (nlh->nlmsg_type) {
 	case ISCSI_UEVENT_BIND_CONN:
-		if (conn->ep) {
-			/*
-			 * For offload boot support where iscsid is restarted
-			 * during the pivot root stage, the ep will be intact
-			 * here when the new iscsid instance starts up and
-			 * reconnects.
-			 */
-			iscsi_ep_disconnect(conn, true);
-		}
-
 		session = iscsi_session_lookup(ev->u.b_conn.sid);
 		if (!session) {
 			err = -EINVAL;
-- 
2.35.1