net/smc: introduce bookkeeping of SMCR link groups

If the smc 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.
Counters for the total number of SMCR link groups and for the total
number of SMCR links per IB device are introduced. smc module unloading
continues only if the total number of SMCR link groups is zero. IB device
removal continues only it the total number of SMCR links per IB 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>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index b7d9fd285c71c3fb0f5d6a7fb92c9d76d6cc8665..42b7fb8ab22bee0139ce25b6edf51c29f746e210 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2038,22 +2038,28 @@ 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 +2091,8 @@ 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:
@@ -2095,10 +2103,10 @@ 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();

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 97e9d21c4d1e651084f40a83d526dede6659724b..cf34b9d96595547f6f45e7f88d31026f7b7b1a56 100644 (file)
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -13,6 +13,7 @@
 #include <linux/if_vlan.h>
 #include <linux/random.h>
 #include <linux/workqueue.h>
+#include <linux/wait.h>
 #include <net/tcp.h>
 #include <net/sock.h>
 #include <rdma/ib_verbs.h>
@@ -39,6 +40,9 @@ 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 +323,8 @@ 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 +412,8 @@ 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 +500,8 @@ 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 +739,15 @@ 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.
@@ -1263,6 +1282,12 @@ static void smc_lgrs_shutdown(void)
        spin_unlock(&smcd_dev_list.lock);
 }
 
+int __init smc_core_init(void)
+{
+       atomic_set(&lgr_cnt, 0);
+       return 0;
+}
+
 /* Called (from smc_exit) when module is removed */
 void smc_core_exit(void)
 {

diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index a428db6cd2e22275626e899c21ca33c7939699cf..c472e12951d1abbf52c8ab44f041b3042605b5e6 100644 (file)
--- a/net/smc/smc_core.h
+++ b/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)

diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index 0ab122e6632800012b1032003ac9ecd61e6de6b2..548632621f4bc952b973c920af68f6477f0acc2b 100644 (file)
--- a/net/smc/smc_ib.c
+++ b/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);

diff --git a/net/smc/smc_ib.h b/net/smc/smc_ib.h
index 6a0069db6cae115f4523b904310c93dfba44ef2a..255db87547d32761c09792c9b608f26be60e95f0 100644 (file)
--- a/net/smc/smc_ib.h
+++ b/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;