net/smc: increase device refcount for added link group

SMCD link groups belong to certain ISM-devices and SMCR link group
links belong to certain IB-devices. Increase the refcount for
these devices, as long as corresponding link groups exist.
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

net/smc/smc_core.c

@@ -248,12 +248,14 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
 	lgr->conns_all = RB_ROOT;
 	if (ini->is_smcd) {
 		/* SMC-D specific settings */
+		get_device(&ini->ism_dev->dev);
 		lgr->peer_gid = ini->ism_gid;
 		lgr->smcd = ini->ism_dev;
 		lgr_list = &ini->ism_dev->lgr_list;
 		lgr_lock = &lgr->smcd->lgr_lock;
 	} else {
 		/* SMC-R specific settings */
+		get_device(&ini->ib_dev->ibdev->dev);
 		lgr->role = smc->listen_smc ? SMC_SERV : SMC_CLNT;
 		memcpy(lgr->peer_systemid, ini->ib_lcl->id_for_peer,
 		       SMC_SYSTEMID_LEN);
@@ -451,10 +453,13 @@ static void smc_lgr_free_bufs(struct smc_link_group *lgr)
 static void smc_lgr_free(struct smc_link_group *lgr)
 {
 	smc_lgr_free_bufs(lgr);
-	if (lgr->is_smcd)
+	if (lgr->is_smcd) {
 		smc_ism_put_vlan(lgr->smcd, lgr->vlan_id);
-	else
+		put_device(&lgr->smcd->dev);
+	} else {
 		smc_link_clear(&lgr->lnk[SMC_SINGLE_LINK]);
+		put_device(&lgr->lnk[SMC_SINGLE_LINK].smcibdev->ibdev->dev);
+	}
 	kfree(lgr);
 }