scsi: iscsi: Fix session removal on shutdown

When the system is shutting down, iscsid is not running so we will not get
a response to the ISCSI_ERR_INVALID_HOST error event. The system shutdown
will then hang waiting on userspace to remove the session.

This has libiscsi force the destruction of the session from the kernel when
iscsi_host_remove() is called from a driver's shutdown callout.

This fixes a regression added in qedi boot with commit d1f2ce77 ("scsi:
qedi: Fix host removal with running sessions") which made qedi use the
common session removal function that waits on userspace instead of rolling
its own kernel based removal.

Link: https://lore.kernel.org/r/20220616222738.5722-7-michael.christie@oracle.com
Fixes: d1f2ce77 ("scsi: qedi: Fix host removal with running sessions")
Tested-by: Nilesh Javali <njavali@marvell.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/infiniband/ulp/iser/iscsi_iser.c

@@ -568,7 +568,7 @@ static void iscsi_iser_session_destroy(struct iscsi_cls_session *cls_session)
 	struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
 
 	iscsi_session_teardown(cls_session);
-	iscsi_host_remove(shost);
+	iscsi_host_remove(shost, false);
 	iscsi_host_free(shost);
 }
 
@@ -685,7 +685,7 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep,
 	return cls_session;
 
 remove_host:
-	iscsi_host_remove(shost);
+	iscsi_host_remove(shost, false);
 free_host:
 	iscsi_host_free(shost);
 	return NULL;

drivers/scsi/be2iscsi/be_main.c

@@ -5745,7 +5745,7 @@ static void beiscsi_remove(struct pci_dev *pcidev)
 	cancel_work_sync(&phba->sess_work);
 
 	beiscsi_iface_destroy_default(phba);
-	iscsi_host_remove(phba->shost);
+	iscsi_host_remove(phba->shost, false);
 	beiscsi_disable_port(phba, 1);
 
 	/* after cancelling boot_work */

drivers/scsi/bnx2i/bnx2i_iscsi.c

@@ -909,7 +909,7 @@ void bnx2i_free_hba(struct bnx2i_hba *hba)
 {
 	struct Scsi_Host *shost = hba->shost;
 
-	iscsi_host_remove(shost);
+	iscsi_host_remove(shost, false);
 	INIT_LIST_HEAD(&hba->ep_ofld_list);
 	INIT_LIST_HEAD(&hba->ep_active_list);
 	INIT_LIST_HEAD(&hba->ep_destroy_list);

drivers/scsi/cxgbi/libcxgbi.c

@@ -328,7 +328,7 @@ void cxgbi_hbas_remove(struct cxgbi_device *cdev)
 		chba = cdev->hbas[i];
 		if (chba) {
 			cdev->hbas[i] = NULL;
-			iscsi_host_remove(chba->shost);
+			iscsi_host_remove(chba->shost, false);
 			pci_dev_put(cdev->pdev);
 			iscsi_host_free(chba->shost);
 		}

drivers/scsi/iscsi_tcp.c

@@ -898,7 +898,7 @@ iscsi_sw_tcp_session_create(struct iscsi_endpoint *ep, uint16_t cmds_max,
 remove_session:
 	iscsi_session_teardown(cls_session);
 remove_host:
-	iscsi_host_remove(shost);
+	iscsi_host_remove(shost, false);
 free_host:
 	iscsi_host_free(shost);
 	return NULL;
@@ -915,7 +915,7 @@ static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session *cls_session)
 	iscsi_tcp_r2tpool_free(cls_session->dd_data);
 	iscsi_session_teardown(cls_session);
 
-	iscsi_host_remove(shost);
+	iscsi_host_remove(shost, false);
 	iscsi_host_free(shost);
 }
 

drivers/scsi/libiscsi.c

@@ -2832,11 +2832,12 @@ static void iscsi_notify_host_removed(struct iscsi_cls_session *cls_session)
 /**
  * iscsi_host_remove - remove host and sessions
  * @shost: scsi host
+ * @is_shutdown: true if called from a driver shutdown callout
  *
  * If there are any sessions left, this will initiate the removal and wait
  * for the completion.
  */
-void iscsi_host_remove(struct Scsi_Host *shost)
+void iscsi_host_remove(struct Scsi_Host *shost, bool is_shutdown)
 {
 	struct iscsi_host *ihost = shost_priv(shost);
 	unsigned long flags;
@@ -2845,7 +2846,11 @@ void iscsi_host_remove(struct Scsi_Host *shost)
 	ihost->state = ISCSI_HOST_REMOVED;
 	spin_unlock_irqrestore(&ihost->lock, flags);
 
-	iscsi_host_for_each_session(shost, iscsi_notify_host_removed);
+	if (!is_shutdown)
+		iscsi_host_for_each_session(shost, iscsi_notify_host_removed);
+	else
+		iscsi_host_for_each_session(shost, iscsi_force_destroy_session);
+
 	wait_event_interruptible(ihost->session_removal_wq,
 				 ihost->num_sessions == 0);
 	if (signal_pending(current))

drivers/scsi/qedi/qedi_main.c

@@ -2414,9 +2414,12 @@ static void __qedi_remove(struct pci_dev *pdev, int mode)
 	int rval;
 	u16 retry = 10;
 
-	if (mode == QEDI_MODE_NORMAL || mode == QEDI_MODE_SHUTDOWN) {
-		iscsi_host_remove(qedi->shost);
+	if (mode == QEDI_MODE_NORMAL)
+		iscsi_host_remove(qedi->shost, false);
+	else if (mode == QEDI_MODE_SHUTDOWN)
+		iscsi_host_remove(qedi->shost, true);
 
+	if (mode == QEDI_MODE_NORMAL || mode == QEDI_MODE_SHUTDOWN) {
 		if (qedi->tmf_thread) {
 			destroy_workqueue(qedi->tmf_thread);
 			qedi->tmf_thread = NULL;
@@ -2791,7 +2794,7 @@ static int __qedi_probe(struct pci_dev *pdev, int mode)
 #ifdef CONFIG_DEBUG_FS
 	qedi_dbg_host_exit(&qedi->dbg_ctx);
 #endif
-	iscsi_host_remove(qedi->shost);
+	iscsi_host_remove(qedi->shost, false);
 stop_iscsi_func:
 	qedi_ops->stop(qedi->cdev);
 stop_slowpath:

include/scsi/libiscsi.h

@@ -411,7 +411,7 @@ extern int iscsi_host_add(struct Scsi_Host *shost, struct device *pdev);
 extern struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
 					  int dd_data_size,
 					  bool xmit_can_sleep);
-extern void iscsi_host_remove(struct Scsi_Host *shost);
+extern void iscsi_host_remove(struct Scsi_Host *shost, bool is_shutdown);
 extern void iscsi_host_free(struct Scsi_Host *shost);
 extern int iscsi_target_alloc(struct scsi_target *starget);
 extern int iscsi_host_get_max_scsi_cmds(struct Scsi_Host *shost,