From 9bb43a58d195d47579692211c65bb116b2a7c6f4 Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Thu, 16 Jun 2022 17:27:36 -0500 Subject: [PATCH] scsi: iscsi: Add helper to remove a session from the kernel [ Upstream commit bb42856bfd54fda1cbc7c470fcf5db1596938f4f ] During qedi shutdown we need to stop the iSCSI layer from sending new nops as pings and from responding to target ones and make sure there is no running connection cleanups. Commit d1f2ce77638d ("scsi: qedi: Fix host removal with running sessions") converted the driver to use the libicsi helper to drive session removal, so the above issues could be handled. The problem is that during system shutdown iscsid will not be running so when we try to remove the root session we will hang waiting for userspace to reply. Add a helper that will drive the destruction of sessions like these during system shutdown. Link: https://lore.kernel.org/r/20220616222738.5722-5-michael.christie@oracle.com Tested-by: Nilesh Javali Reviewed-by: Nilesh Javali Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/scsi_transport_iscsi.c | 49 +++++++++++++++++++++++++++++ include/scsi/scsi_transport_iscsi.h | 1 + 2 files changed, 50 insertions(+) diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c index a410d0b8a445..2a38cd2d24ef 100644 --- a/drivers/scsi/scsi_transport_iscsi.c +++ b/drivers/scsi/scsi_transport_iscsi.c @@ -2341,6 +2341,55 @@ static void iscsi_cleanup_conn_work_fn(struct work_struct *work) ISCSI_DBG_TRANS_CONN(conn, "cleanup done.\n"); } +static int iscsi_iter_force_destroy_conn_fn(struct device *dev, void *data) +{ + struct iscsi_transport *transport; + struct iscsi_cls_conn *conn; + + if (!iscsi_is_conn_dev(dev)) + return 0; + + conn = iscsi_dev_to_conn(dev); + transport = conn->transport; + + if (READ_ONCE(conn->state) != ISCSI_CONN_DOWN) + iscsi_if_stop_conn(conn, STOP_CONN_TERM); + + transport->destroy_conn(conn); + return 0; +} + +/** + * iscsi_force_destroy_session - destroy a session from the kernel + * @session: session to destroy + * + * Force the destruction of a session from the kernel. This should only be + * used when userspace is no longer running during system shutdown. + */ +void iscsi_force_destroy_session(struct iscsi_cls_session *session) +{ + struct iscsi_transport *transport = session->transport; + unsigned long flags; + + WARN_ON_ONCE(system_state == SYSTEM_RUNNING); + + spin_lock_irqsave(&sesslock, flags); + if (list_empty(&session->sess_list)) { + spin_unlock_irqrestore(&sesslock, flags); + /* + * Conn/ep is already freed. Session is being torn down via + * async path. For shutdown we don't care about it so return. + */ + return; + } + spin_unlock_irqrestore(&sesslock, flags); + + device_for_each_child(&session->dev, NULL, + iscsi_iter_force_destroy_conn_fn); + transport->destroy_session(session); +} +EXPORT_SYMBOL_GPL(iscsi_force_destroy_session); + void iscsi_free_session(struct iscsi_cls_session *session) { ISCSI_DBG_TRANS_SESSION(session, "Freeing session\n"); diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h index 9acb8422f680..d6eab7cb221a 100644 --- a/include/scsi/scsi_transport_iscsi.h +++ b/include/scsi/scsi_transport_iscsi.h @@ -442,6 +442,7 @@ extern struct iscsi_cls_session *iscsi_create_session(struct Scsi_Host *shost, struct iscsi_transport *t, int dd_size, unsigned int target_id); +extern void iscsi_force_destroy_session(struct iscsi_cls_session *session); extern void iscsi_remove_session(struct iscsi_cls_session *session); extern void iscsi_free_session(struct iscsi_cls_session *session); extern struct iscsi_cls_conn *iscsi_alloc_conn(struct iscsi_cls_session *sess,