Merge branch 'smc-last-part-of-termination-improvements'

Karsten Graul says:

====================
last part of termination improvements

Patches 1 and 2 finish the set of termination patches, introducing
a reboot handler that terminates all link groups. Patch 3 adds an
rcu_barrier before the module is unloaded, and patch 4 is cleanup.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/af_smc.c

@@ -25,6 +25,7 @@
 #include <linux/in.h>
 #include <linux/sched/signal.h>
 #include <linux/if_vlan.h>
+#include <linux/rcupdate_wait.h>
 
 #include <net/sock.h>
 #include <net/tcp.h>
@@ -2038,22 +2039,28 @@ static int __init smc_init(void)
 	if (rc)
 		goto out_pernet_subsys;
 
+	rc = smc_core_init();
+	if (rc) {
+		pr_err("%s: smc_core_init fails with %d\n", __func__, rc);
+		goto out_pnet;
+	}
+
 	rc = smc_llc_init();
 	if (rc) {
 		pr_err("%s: smc_llc_init fails with %d\n", __func__, rc);
-		goto out_pnet;
+		goto out_core;
 	}
 
 	rc = smc_cdc_init();
 	if (rc) {
 		pr_err("%s: smc_cdc_init fails with %d\n", __func__, rc);
-		goto out_pnet;
+		goto out_core;
 	}
 
 	rc = proto_register(&smc_proto, 1);
 	if (rc) {
 		pr_err("%s: proto_register(v4) fails with %d\n", __func__, rc);
-		goto out_pnet;
+		goto out_core;
 	}
 
 	rc = proto_register(&smc_proto6, 1);
@@ -2085,6 +2092,8 @@ out_proto6:
 	proto_unregister(&smc_proto6);
 out_proto:
 	proto_unregister(&smc_proto);
+out_core:
+	smc_core_exit();
 out_pnet:
 	smc_pnet_exit();
 out_pernet_subsys:
@@ -2095,14 +2104,15 @@ out_pernet_subsys:
 
 static void __exit smc_exit(void)
 {
-	smc_core_exit();
 	static_branch_disable(&tcp_have_smc);
-	smc_ib_unregister_client();
 	sock_unregister(PF_SMC);
+	smc_core_exit();
+	smc_ib_unregister_client();
 	proto_unregister(&smc_proto6);
 	proto_unregister(&smc_proto);
 	smc_pnet_exit();
 	unregister_pernet_subsys(&smc_net_ops);
+	rcu_barrier();
 }
 
 module_init(smc_init);

net/smc/smc_close.c

@@ -20,8 +20,6 @@
 #include "smc_cdc.h"
 #include "smc_close.h"
 
-#define SMC_CLOSE_WAIT_LISTEN_CLCSOCK_TIME	(5 * HZ)
-
 /* release the clcsock that is assigned to the smc_sock */
 void smc_clcsock_release(struct smc_sock *smc)
 {

net/smc/smc_core.c

@@ -13,6 +13,8 @@
 #include <linux/if_vlan.h>
 #include <linux/random.h>
 #include <linux/workqueue.h>
+#include <linux/wait.h>
+#include <linux/reboot.h>
 #include <net/tcp.h>
 #include <net/sock.h>
 #include <rdma/ib_verbs.h>
@@ -39,6 +41,9 @@ static struct smc_lgr_list smc_lgr_list = {	/* established link groups */
 	.num = 0,
 };
 
+static atomic_t lgr_cnt;		/* number of existing link groups */
+static DECLARE_WAIT_QUEUE_HEAD(lgrs_deleted);
+
 static void smc_buf_free(struct smc_link_group *lgr, bool is_rmb,
 			 struct smc_buf_desc *buf_desc);
 
@@ -319,6 +324,8 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
 		rc = smc_wr_create_link(lnk);
 		if (rc)
 			goto destroy_qp;
+		atomic_inc(&lgr_cnt);
+		atomic_inc(&ini->ib_dev->lnk_cnt);
 	}
 	smc->conn.lgr = lgr;
 	spin_lock_bh(lgr_lock);
@@ -406,6 +413,8 @@ static void smc_link_clear(struct smc_link *lnk)
 	smc_ib_destroy_queue_pair(lnk);
 	smc_ib_dealloc_protection_domain(lnk);
 	smc_wr_free_link_mem(lnk);
+	if (!atomic_dec_return(&lnk->smcibdev->lnk_cnt))
+		wake_up(&lnk->smcibdev->lnks_deleted);
 }
 
 static void smcr_buf_free(struct smc_link_group *lgr, bool is_rmb,
@@ -492,6 +501,8 @@ static void smc_lgr_free(struct smc_link_group *lgr)
 	} else {
 		smc_link_clear(&lgr->lnk[SMC_SINGLE_LINK]);
 		put_device(&lgr->lnk[SMC_SINGLE_LINK].smcibdev->ibdev->dev);
+		if (!atomic_dec_return(&lgr_cnt))
+			wake_up(&lgrs_deleted);
 	}
 	kfree(lgr);
 }
@@ -729,6 +740,15 @@ void smc_smcr_terminate_all(struct smc_ib_device *smcibdev)
 		list_del_init(&lgr->list);
 		__smc_lgr_terminate(lgr, false);
 	}
+
+	if (smcibdev) {
+		if (atomic_read(&smcibdev->lnk_cnt))
+			wait_event(smcibdev->lnks_deleted,
+				   !atomic_read(&smcibdev->lnk_cnt));
+	} else {
+		if (atomic_read(&lgr_cnt))
+			wait_event(lgrs_deleted, !atomic_read(&lgr_cnt));
+	}
 }
 
 /* Determine vlan of internal TCP socket.
@@ -1263,8 +1283,27 @@ static void smc_lgrs_shutdown(void)
 	spin_unlock(&smcd_dev_list.lock);
 }
 
+static int smc_core_reboot_event(struct notifier_block *this,
+				 unsigned long event, void *ptr)
+{
+	smc_lgrs_shutdown();
+
+	return 0;
+}
+
+static struct notifier_block smc_reboot_notifier = {
+	.notifier_call = smc_core_reboot_event,
+};
+
+int __init smc_core_init(void)
+{
+	atomic_set(&lgr_cnt, 0);
+	return register_reboot_notifier(&smc_reboot_notifier);
+}
+
 /* Called (from smc_exit) when module is removed */
 void smc_core_exit(void)
 {
+	unregister_reboot_notifier(&smc_reboot_notifier);
 	smc_lgrs_shutdown();
 }

net/smc/smc_core.h

@@ -318,6 +318,7 @@ void smc_conn_free(struct smc_connection *conn);
 int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini);
 void smcd_conn_free(struct smc_connection *conn);
 void smc_lgr_schedule_free_work_fast(struct smc_link_group *lgr);
+int smc_core_init(void);
 void smc_core_exit(void);
 
 static inline struct smc_link_group *smc_get_lgr(struct smc_link *link)

net/smc/smc_ib.c

@@ -15,6 +15,7 @@
 #include <linux/random.h>
 #include <linux/workqueue.h>
 #include <linux/scatterlist.h>
+#include <linux/wait.h>
 #include <rdma/ib_verbs.h>
 #include <rdma/ib_cache.h>
 
@@ -543,7 +544,8 @@ static void smc_ib_add_dev(struct ib_device *ibdev)
 
 	smcibdev->ibdev = ibdev;
 	INIT_WORK(&smcibdev->port_event_work, smc_ib_port_event_work);
-
+	atomic_set(&smcibdev->lnk_cnt, 0);
+	init_waitqueue_head(&smcibdev->lnks_deleted);
 	spin_lock(&smc_ib_devices.lock);
 	list_add_tail(&smcibdev->list, &smc_ib_devices.list);
 	spin_unlock(&smc_ib_devices.lock);

net/smc/smc_ib.h

@@ -14,6 +14,7 @@
 
 #include <linux/interrupt.h>
 #include <linux/if_ether.h>
+#include <linux/wait.h>
 #include <rdma/ib_verbs.h>
 #include <net/smc.h>
 
@@ -48,6 +49,8 @@ struct smc_ib_device {				/* ib-device infos for smc */
 	struct work_struct	port_event_work;
 	unsigned long		port_event_mask;
 	DECLARE_BITMAP(ports_going_away, SMC_MAX_PORTS);
+	atomic_t		lnk_cnt;	/* number of links on ibdev */
+	wait_queue_head_t	lnks_deleted;	/* wait 4 removal of all links*/
 };
 
 struct smc_buf_desc;