net/smc: improve delete link processing

Send an orderly DELETE LINK request before termination of a link group,
add support for client triggered DELETE LINK processing. And send a
disorderly DELETE LINK before module is unloaded.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 42 insertions, 5 deletions

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 90c10ae9ae09..a46418f45ecd 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -30,6 +30,7 @@
 #define SMC_LGR_NUM_INCR		256
 #define SMC_LGR_FREE_DELAY_SERV		(600 * HZ)
 #define SMC_LGR_FREE_DELAY_CLNT		(SMC_LGR_FREE_DELAY_SERV + 10 * HZ)
+#define SMC_LGR_FREE_DELAY_FAST		(8 * HZ)
 
 static struct smc_lgr_list smc_lgr_list = {	/* established link groups */
 	.lock = __SPIN_LOCK_UNLOCKED(smc_lgr_list.lock),
@@ -51,6 +52,11 @@ static void smc_lgr_schedule_free_work(struct smc_link_group *lgr)
 			 SMC_LGR_FREE_DELAY_CLNT : SMC_LGR_FREE_DELAY_SERV);
 }
 
+void smc_lgr_schedule_free_work_fast(struct smc_link_group *lgr)
+{
+	mod_delayed_work(system_wq, &lgr->free_work, SMC_LGR_FREE_DELAY_FAST);
+}
+
 /* Register connection's alert token in our lookup structure.
  * To use rbtrees we have to implement our own insert core.
  * Requires @conns_lock
@@ -133,6 +139,20 @@ static void smc_lgr_unregister_conn(struct smc_connection *conn)
 	smc_lgr_schedule_free_work(lgr);
 }
 
+/* Send delete link, either as client to request the initiation
+ * of the DELETE LINK sequence from server; or as server to
+ * initiate the delete processing. See smc_llc_rx_delete_link().
+ */
+static int smc_link_send_delete(struct smc_link *lnk)
+{
+	if (lnk->state == SMC_LNK_ACTIVE &&
+	    !smc_llc_send_delete_link(lnk, SMC_LLC_REQ, true)) {
+		smc_llc_link_deleting(lnk);
+		return 0;
+	}
+	return -ENOTCONN;
+}
+
 static void smc_lgr_free_work(struct work_struct *work)
 {
 	struct smc_link_group *lgr = container_of(to_delayed_work(work),
@@ -153,10 +173,21 @@ static void smc_lgr_free_work(struct work_struct *work)
 	list_del_init(&lgr->list); /* remove from smc_lgr_list */
 free:
 	spin_unlock_bh(&smc_lgr_list.lock);
+
+	if (!lgr->is_smcd && !lgr->terminating)	{
+		/* try to send del link msg, on error free lgr immediately */
+		if (!smc_link_send_delete(&lgr->lnk[SMC_SINGLE_LINK])) {
+			/* reschedule in case we never receive a response */
+			smc_lgr_schedule_free_work(lgr);
+			return;
+		}
+	}
+
 	if (!delayed_work_pending(&lgr->free_work)) {
-		if (!lgr->is_smcd &&
-		    lgr->lnk[SMC_SINGLE_LINK].state != SMC_LNK_INACTIVE)
-			smc_llc_link_inactive(&lgr->lnk[SMC_SINGLE_LINK]);
+		struct smc_link *lnk = &lgr->lnk[SMC_SINGLE_LINK];
+
+		if (!lgr->is_smcd && lnk->state != SMC_LNK_INACTIVE)
+			smc_llc_link_inactive(lnk);
 		smc_lgr_free(lgr);
 	}
 }
@@ -984,8 +1015,14 @@ void smc_core_exit(void)
 	spin_unlock_bh(&smc_lgr_list.lock);
 	list_for_each_entry_safe(lgr, lg, &lgr_freeing_list, list) {
 		list_del_init(&lgr->list);
-		if (!lgr->is_smcd)
-			smc_llc_link_inactive(&lgr->lnk[SMC_SINGLE_LINK]);
+		if (!lgr->is_smcd) {
+			struct smc_link *lnk = &lgr->lnk[SMC_SINGLE_LINK];
+
+			if (lnk->state == SMC_LNK_ACTIVE)
+				smc_llc_send_delete_link(lnk, SMC_LLC_REQ,
+							 false);
+			smc_llc_link_inactive(lnk);
+		}
 		cancel_delayed_work_sync(&lgr->free_work);
 		smc_lgr_free(lgr); /* free link group */
 	}