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

Sasha Levin
2022-04-19T18:13:28Z

From: Mike Christie <michael.christie@oracle.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@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>
---
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