scsi: iscsi: Fix offload conn cleanup when iscsid restarts

[ 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@marvell.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 126f6f2..03cda2d 100644 (file)
--- 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)
 {
@@ -2276,6 +2293,16 @@ static int iscsi_if_stop_conn(struct iscsi_transport *transport,
                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.
                 */
                if (!test_and_set_bit(ISCSI_CLS_CONN_BIT_CLEANUP, &conn->flags)) {
@@ -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;