LU-15137 socklnd: decrement connection counters on close

To gracefully handle potential race with delayed connection create,
decrement connection counters per type as connections are being
closed.

Lustre-change: https://review.whamcloud.com/45422
Lustre-commit: 7e26413aa85fdc931721cde36bae3bf2bb97e63f

Test-Parameters: trivial testlist=sanity-lnet
Fixes: e8842e86 ("LU-12815 socklnd: add conns_per_peer parameter")
Signed-off-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Change-Id: Ieb3b44701e4999ea1fe63234162dd5878d65958a
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-by: Cyril Bordage <cbordage@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/46035
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>

diff --git a/lnet/klnds/socklnd/socklnd.c b/lnet/klnds/socklnd/socklnd.c
index 53b8367..26380aa 100644 (file)
--- a/lnet/klnds/socklnd/socklnd.c
+++ b/lnet/klnds/socklnd/socklnd.c
@@ -358,7 +358,9 @@ ksocknal_incr_conn_count(struct ksock_route *route,
        switch (type) {
        case SOCKLND_CONN_CONTROL:
                route->ksnr_ctrl_conn_count++;
-               /* there's a single control connection per peer */
+               /* there's a single control connection per peer,
+                * two in case of loopback
+                */
                route->ksnr_connected |= BIT(type);
                break;
        case SOCKLND_CONN_BULK_IN:
@@ -390,6 +392,48 @@ ksocknal_incr_conn_count(struct ksock_route *route,
               *ksocknal_tunables.ksnd_conns_per_peer);
 }
 
+
+static void
+ksocknal_decr_conn_count(struct ksock_route *route,
+                        int type)
+{
+       int max_conns = *ksocknal_tunables.ksnd_conns_per_peer;
+
+       route->ksnr_conn_count--;
+
+       /* check if all connections of the given type got created */
+       switch (type) {
+       case SOCKLND_CONN_CONTROL:
+               route->ksnr_ctrl_conn_count--;
+               /* there's a single control connection per peer,
+                * two in case of loopback
+                */
+               if (route->ksnr_ctrl_conn_count == 0)
+                       route->ksnr_connected &= ~BIT(type);
+               break;
+       case SOCKLND_CONN_BULK_IN:
+               route->ksnr_blki_conn_count--;
+               if (route->ksnr_blki_conn_count < max_conns)
+                       route->ksnr_connected &= ~BIT(type);
+               break;
+       case SOCKLND_CONN_BULK_OUT:
+               route->ksnr_blko_conn_count--;
+               if (route->ksnr_blko_conn_count < max_conns)
+                       route->ksnr_connected &= ~BIT(type);
+               break;
+       case SOCKLND_CONN_ANY:
+               if (route->ksnr_conn_count < max_conns)
+                       route->ksnr_connected &= ~BIT(type);
+               break;
+       default:
+               LBUG();
+               break;
+       }
+
+       CDEBUG(D_NET, "Del conn type %d, ksnr_connected %x\n",
+              type, route->ksnr_connected);
+}
+
 static void
 ksocknal_associate_route_conn_locked(struct ksock_route *route, struct ksock_conn *conn)
 {
@@ -1500,7 +1544,8 @@ ksocknal_close_conn_locked(struct ksock_conn *conn, int error)
        struct ksock_peer_ni *peer_ni = conn->ksnc_peer;
        struct ksock_route *route;
        struct ksock_conn *conn2;
-       struct list_head *tmp;
+       int conn_count;
+       int duplicate_count = 0;
 
        LASSERT(peer_ni->ksnp_error == 0);
        LASSERT(!conn->ksnc_closing);
@@ -1514,25 +1559,28 @@ ksocknal_close_conn_locked(struct ksock_conn *conn, int error)
                /* dissociate conn from route... */
                LASSERT(!route->ksnr_deleted);
 
+               conn_count = ksocknal_get_conn_count_by_type(route,
+                                                            conn->ksnc_type);
                /* connected bit is set only if all connections
                 * of the given type got created
                 */
-               if (ksocknal_get_conn_count_by_type(route, conn->ksnc_type) ==
-                   *ksocknal_tunables.ksnd_conns_per_peer)
+               if (conn_count == *ksocknal_tunables.ksnd_conns_per_peer)
                        LASSERT((route->ksnr_connected &
                                BIT(conn->ksnc_type)) != 0);
-               conn2 = NULL;
-               list_for_each(tmp, &peer_ni->ksnp_conns) {
-                       conn2 = list_entry(tmp, struct ksock_conn, ksnc_list);
-
-                       if (conn2->ksnc_route == route &&
-                           conn2->ksnc_type == conn->ksnc_type)
-                               break;
 
-                       conn2 = NULL;
+               if (conn_count == 1) {
+                       list_for_each_entry(conn2, &peer_ni->ksnp_conns,
+                                           ksnc_list) {
+                               if (conn2->ksnc_route == route &&
+                                   conn2->ksnc_type == conn->ksnc_type)
+                                       duplicate_count += 1;
+                       }
+                       if (duplicate_count > 0)
+                               CERROR("Found %d duplicate conns type %d\n",
+                                      duplicate_count,
+                                      conn->ksnc_type);
                }
-               if (conn2 == NULL)
-                       route->ksnr_connected &= ~(1 << conn->ksnc_type);
+               ksocknal_decr_conn_count(route, conn->ksnc_type);
 
                conn->ksnc_route = NULL;