loop/usb/vhost-scsi/xen-scsiback: Fix use of __transport_register_session

This patch changes loopback, usb-gadget, vhost-scsi and xen-scsiback
fabric code to invoke transport_register_session() instead of the
unprotected flavour, to ensure se_tpg->session_lock is taken when
adding new session list nodes to se_tpg->tpg_sess_list.

Note that since these four fabric drivers already hold their own
internal TPG mutexes when accessing se_tpg->tpg_sess_list, and
consist of a single se_session created through configfs attribute
access, no list corruption can currently occur.

So for correctness sake, go ahead and use the se_tpg->session_lock
protected version for these four fabric drivers.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 8d4f3f1ff799..71df240a467a 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1956,10 +1956,9 @@ static int vhost_scsi_make_nexus(struct vhost_scsi_tpg *tpg,
                 goto out;
         }
         /*
-         * Now register the TCM vhost virtual I_T Nexus as active with the
-         * call to __transport_register_session()
+         * Now register the TCM vhost virtual I_T Nexus as active.
          */
-        __transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
+        transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
                         tv_nexus->tvn_se_sess, tv_nexus);
         tpg->tpg_nexus = tv_nexus;