From: Ursula Braun <ubraun@linux.ibm.com>
Date: Thu, 14 Nov 2019 13:02:43 +0100
Subject: net/smc: introduce bookkeeping of SMCD link groups
Git-commit: 5edd6b9cb8d7c6c346c93c52a53735591127e879
Patch-mainline: v5.5-rc1
References: jsc#SLE-7395

If the ism module is unloaded return control from exit routine only,
if all link groups are freed.
If an IB device is thrown away return control from device removal only,
if all link groups belonging to this device are freed.
A counters for the total number of SMCD link groups per ISM device is
introduced. ism module unloading continues only if the total number of
SMCD link groups for all ISM devices is zero. ISM device
removal continues only it the total number of SMCD link groups per ISM
device has decreased to zero.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 include/net/smc.h  |    2 ++
 net/smc/smc_core.c |    6 ++++++
 net/smc/smc_ism.c  |    1 +
 3 files changed, 9 insertions(+)

--- a/include/net/smc.h
+++ b/include/net/smc.h
@@ -79,6 +79,8 @@ struct smcd_dev {
 	bool pnetid_by_user;
 	struct list_head lgr_list;
 	spinlock_t lgr_lock;
+	atomic_t lgr_cnt;
+	wait_queue_head_t lgrs_deleted;
 	u8 going_away : 1;
 };
 
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -276,6 +276,7 @@ static int smc_lgr_create(struct smc_soc
 		lgr_list = &ini->ism_dev->lgr_list;
 		lgr_lock = &lgr->smcd->lgr_lock;
 		lgr->peer_shutdown = 0;
+		atomic_inc(&ini->ism_dev->lgr_cnt);
 	} else {
 		/* SMC-R specific settings */
 		get_device(&ini->ib_dev->ibdev->dev);
@@ -486,6 +487,8 @@ static void smc_lgr_free(struct smc_link
 			smc_ism_put_vlan(lgr->smcd, lgr->vlan_id);
 			put_device(&lgr->smcd->dev);
 		}
+		if (!atomic_dec_return(&lgr->smcd->lgr_cnt))
+			wake_up(&lgr->smcd->lgrs_deleted);
 	} else {
 		smc_link_clear(&lgr->lnk[SMC_SINGLE_LINK]);
 		put_device(&lgr->lnk[SMC_SINGLE_LINK].smcibdev->ibdev->dev);
@@ -685,6 +688,9 @@ void smc_smcd_terminate_all(struct smcd_
 		list_del_init(&lgr->list);
 		__smc_lgr_terminate(lgr, false);
 	}
+
+	if (atomic_read(&smcd->lgr_cnt))
+		wait_event(smcd->lgrs_deleted, !atomic_read(&smcd->lgr_cnt));
 }
 
 /* Determine vlan of internal TCP socket.
--- a/net/smc/smc_ism.c
+++ b/net/smc/smc_ism.c
@@ -302,6 +302,7 @@ struct smcd_dev *smcd_alloc_dev(struct d
 	spin_lock_init(&smcd->lgr_lock);
 	INIT_LIST_HEAD(&smcd->vlan);
 	INIT_LIST_HEAD(&smcd->lgr_list);
+	init_waitqueue_head(&smcd->lgrs_deleted);
 	smcd->event_wq = alloc_ordered_workqueue("ism_evt_wq-%s)",
 						 WQ_MEM_RECLAIM, name);
 	if (!smcd->event_wq) {