vcl: improve shutdown()
[vpp.git] / src / vcl / vcl_locked.c
index 35061e7..ea22bcd 100644 (file)
@@ -38,6 +38,7 @@ typedef struct vcl_locked_session_
 
 typedef struct vls_worker_
 {
+  clib_rwlock_t sh_to_vlsh_table_lock; /** valid for multithread workers */
   vcl_locked_session_t *vls_pool;
   uword *session_handle_to_vlsh_table;
   u32 wrk_index;
@@ -50,7 +51,6 @@ typedef struct vls_local_
   pthread_mutex_t vls_mt_mq_mlock;
   pthread_mutex_t vls_mt_spool_mlock;
   volatile u8 select_mp_check;
-  volatile u8 epoll_mp_check;
 } vls_process_local_t;
 
 static vls_process_local_t vls_local;
@@ -63,10 +63,19 @@ typedef struct vls_main_
   /** Pool of data shared by sessions owned by different workers */
   vls_shared_data_t *shared_data_pool;
   clib_rwlock_t shared_data_lock;
+  /** Lock to protect rpc among workers */
+  clib_spinlock_t worker_rpc_lock;
 } vls_main_t;
 
 vls_main_t *vlsm;
 
+typedef enum
+{
+  VLS_RPC_STATE_INIT,
+  VLS_RPC_STATE_SUCCESS,
+  VLS_RPC_STATE_SESSION_NOT_EXIST,
+} vls_rpc_state_e;
+
 typedef enum vls_rpc_msg_type_
 {
   VLS_RPC_CLONE_AND_SHARE,
@@ -97,13 +106,11 @@ typedef struct vls_sess_cleanup_msg_
 
 void vls_send_session_cleanup_rpc (vcl_worker_t * wrk,
                                   u32 dst_wrk_index, u32 dst_session_index);
-void vls_send_clone_and_share_rpc (vcl_worker_t * wrk,
-                                  vcl_locked_session_t * vls,
+void vls_send_clone_and_share_rpc (vcl_worker_t *wrk, u32 origin_vls_index,
                                   u32 session_index, u32 vls_wrk_index,
                                   u32 dst_wrk_index, u32 dst_vls_index,
                                   u32 dst_session_index);
 
-
 static inline u32
 vls_get_worker_index (void)
 {
@@ -219,7 +226,10 @@ vls_mt_add (void)
    * vcl worker with vpp. Otherwise, all threads use the same vcl worker, so
    * update the vcl worker's thread local worker index variable */
   if (vls_mt_wrk_supported ())
-    vls_register_vcl_worker ();
+    {
+      if (vppcom_worker_register () != VPPCOM_OK)
+       VERR ("failed to register worker");
+    }
   else
     vcl_set_worker_index (vlsl->vls_wrk_index);
 }
@@ -302,6 +312,8 @@ vls_worker_alloc (void)
   vls_worker_t *wrk;
 
   pool_get_zero (vlsm->workers, wrk);
+  if (vls_mt_wrk_supported ())
+    clib_rwlock_init (&wrk->sh_to_vlsh_table_lock);
   wrk->wrk_index = vcl_get_worker_index ();
 }
 
@@ -309,6 +321,8 @@ static void
 vls_worker_free (vls_worker_t * wrk)
 {
   hash_free (wrk->session_handle_to_vlsh_table);
+  if (vls_mt_wrk_supported ())
+    clib_rwlock_free (&wrk->sh_to_vlsh_table_lock);
   pool_free (wrk->vls_pool);
   pool_put (vlsm->workers, wrk);
 }
@@ -321,6 +335,37 @@ vls_worker_get (u32 wrk_index)
   return pool_elt_at_index (vlsm->workers, wrk_index);
 }
 
+static void
+vls_sh_to_vlsh_table_add (vls_worker_t *wrk, vcl_session_handle_t sh, u32 vlsh)
+{
+  if (vls_mt_wrk_supported ())
+    clib_rwlock_writer_lock (&wrk->sh_to_vlsh_table_lock);
+  hash_set (wrk->session_handle_to_vlsh_table, sh, vlsh);
+  if (vls_mt_wrk_supported ())
+    clib_rwlock_writer_unlock (&wrk->sh_to_vlsh_table_lock);
+}
+
+static void
+vls_sh_to_vlsh_table_del (vls_worker_t *wrk, vcl_session_handle_t sh)
+{
+  if (vls_mt_wrk_supported ())
+    clib_rwlock_writer_lock (&wrk->sh_to_vlsh_table_lock);
+  hash_unset (wrk->session_handle_to_vlsh_table, sh);
+  if (vls_mt_wrk_supported ())
+    clib_rwlock_writer_unlock (&wrk->sh_to_vlsh_table_lock);
+}
+
+static uword *
+vls_sh_to_vlsh_table_get (vls_worker_t *wrk, vcl_session_handle_t sh)
+{
+  if (vls_mt_wrk_supported ())
+    clib_rwlock_reader_lock (&wrk->sh_to_vlsh_table_lock);
+  uword *vlshp = hash_get (wrk->session_handle_to_vlsh_table, sh);
+  if (vls_mt_wrk_supported ())
+    clib_rwlock_reader_unlock (&wrk->sh_to_vlsh_table_lock);
+  return vlshp;
+}
+
 static vls_handle_t
 vls_alloc (vcl_session_handle_t sh)
 {
@@ -334,7 +379,7 @@ vls_alloc (vcl_session_handle_t sh)
   vls->worker_index = vppcom_session_worker (sh);
   vls->vls_index = vls - wrk->vls_pool;
   vls->shared_data_index = ~0;
-  hash_set (wrk->session_handle_to_vlsh_table, sh, vls->vls_index);
+  vls_sh_to_vlsh_table_add (wrk, sh, vls->vls_index);
   if (vls_mt_wrk_supported ())
     {
       hash_set (vls->vcl_wrk_index_to_session_index, vls->worker_index,
@@ -362,8 +407,8 @@ vls_free (vcl_locked_session_t * vls)
   vls_worker_t *wrk = vls_worker_get_current ();
 
   ASSERT (vls != 0);
-  hash_unset (wrk->session_handle_to_vlsh_table,
-             vcl_session_handle_from_index (vls->session_index));
+  vls_sh_to_vlsh_table_del (
+    wrk, vcl_session_handle_from_index (vls->session_index));
   clib_spinlock_free (&vls->lock);
   pool_put (wrk->vls_pool, vls);
 }
@@ -442,10 +487,10 @@ vls_handle_t
 vls_si_wi_to_vlsh (u32 session_index, u32 vcl_wrk_index)
 {
   vls_worker_t *wrk = vls_worker_get_current ();
-  uword *vlshp;
-  vlshp = hash_get (wrk->session_handle_to_vlsh_table,
-                   vcl_session_handle_from_wrk_session_index (session_index,
-                                                              vcl_wrk_index));
+  uword *vlshp = vls_sh_to_vlsh_table_get (
+    wrk,
+    vcl_session_handle_from_wrk_session_index (session_index, vcl_wrk_index));
+
   return vlshp ? *vlshp : VLS_INVALID_HANDLE;
 }
 
@@ -736,7 +781,7 @@ vls_share_sessions (vls_worker_t * vls_parent_wrk, vls_worker_t * vls_wrk)
   vcl_locked_session_t *vls, *parent_vls;
 
   /* *INDENT-OFF* */
-  pool_foreach (vls, vls_wrk->vls_pool, ({
+  pool_foreach (vls, vls_wrk->vls_pool)  {
     /* Initialize sharing on parent session */
     if (vls->shared_data_index == ~0)
       {
@@ -745,7 +790,7 @@ vls_share_sessions (vls_worker_t * vls_parent_wrk, vls_worker_t * vls_wrk)
        vls->shared_data_index = parent_vls->shared_data_index;
       }
     vls_share_session (vls_wrk, vls);
-  }));
+  }
   /* *INDENT-ON* */
 }
 
@@ -846,12 +891,13 @@ vls_mt_session_should_migrate (vcl_locked_session_t * vls)
          && vls->worker_index != vcl_get_worker_index ());
 }
 
-static void
-vls_mt_session_migrate (vcl_locked_session_t * vls)
+static vcl_locked_session_t *
+vls_mt_session_migrate (vcl_locked_session_t *vls)
 {
   u32 wrk_index = vcl_get_worker_index ();
   vcl_worker_t *wrk;
-  u32 src_sid, sid;
+  vls_worker_t *vls_wrk = vls_worker_get_current ();
+  u32 src_sid, sid, vls_index, own_vcl_wrk_index;
   vcl_session_t *session;
   uword *p;
 
@@ -865,7 +911,7 @@ vls_mt_session_migrate (vcl_locked_session_t * vls)
     {
       vls->worker_index = wrk_index;
       vls->session_index = (u32) p[0];
-      return;
+      return vls;
     }
 
   /*
@@ -878,40 +924,70 @@ vls_mt_session_migrate (vcl_locked_session_t * vls)
     {
       VERR ("session in owner worker(%u) is free", vls->owner_vcl_wrk_index);
       ASSERT (0);
-      return;
+      vls_unlock (vls);
+      vls_mt_table_runlock ();
+      return 0;
     }
 
   src_sid = (u32) p[0];
   wrk = vcl_worker_get_current ();
   session = vcl_session_alloc (wrk);
   sid = session->session_index;
-  vls_send_clone_and_share_rpc (wrk, vls, sid, vls_get_worker_index (),
-                               vls->owner_vcl_wrk_index, vls->vls_index,
-                               src_sid);
-  session->session_index = sid;
-  vls->worker_index = wrk_index;
-  vls->session_index = sid;
-  hash_set (vls->vcl_wrk_index_to_session_index, wrk_index, sid);
   VDBG (1, "migrate session of worker (session): %u (%u) -> %u (%u)",
        vls->owner_vcl_wrk_index, src_sid, wrk_index, sid);
 
-  if (PREDICT_FALSE ((session->flags & VCL_SESSION_F_IS_VEP)
-                    && session->vep.next_sh != ~0))
+  /* Drop lock to prevent dead lock when dst wrk trying to get lock. */
+  vls_index = vls->vls_index;
+  own_vcl_wrk_index = vls->owner_vcl_wrk_index;
+  vls_unlock (vls);
+  vls_mt_table_runlock ();
+  vls_send_clone_and_share_rpc (wrk, vls_index, sid, vls_get_worker_index (),
+                               own_vcl_wrk_index, vls_index, src_sid);
+
+  if (PREDICT_FALSE (wrk->rpc_done == VLS_RPC_STATE_SESSION_NOT_EXIST))
+    {
+      VWRN ("session %u not exist", src_sid);
+      goto err;
+    }
+  else if (PREDICT_FALSE (wrk->rpc_done == VLS_RPC_STATE_INIT))
+    {
+      VWRN ("failed to wait rpc response");
+      goto err;
+    }
+  else if (PREDICT_FALSE ((session->flags & VCL_SESSION_F_IS_VEP) &&
+                         session->vep.next_sh != ~0))
     {
-      /* TODO: rollback? */
       VERR ("can't migrate nonempty epoll session");
       ASSERT (0);
-      return;
+      goto err;
     }
   else if (PREDICT_FALSE (!(session->flags & VCL_SESSION_F_IS_VEP) &&
                          session->session_state != VCL_STATE_CLOSED))
     {
-      /* TODO: rollback? */
       VERR ("migrate NOT supported, session_status (%u)",
            session->session_state);
       ASSERT (0);
-      return;
+      goto err;
     }
+
+  vls = vls_get_w_dlock (vls_index);
+  if (PREDICT_FALSE (!vls))
+    {
+      VWRN ("failed to get vls %u", vls_index);
+      goto err;
+    }
+
+  session->session_index = sid;
+  vls->worker_index = wrk_index;
+  vls->session_index = sid;
+  hash_set (vls->vcl_wrk_index_to_session_index, wrk_index, sid);
+  vls_sh_to_vlsh_table_add (vls_wrk, vcl_session_handle (session),
+                           vls->vls_index);
+  return vls;
+
+err:
+  vcl_session_free (wrk, session);
+  return 0;
 }
 
 static inline void
@@ -921,20 +997,24 @@ vls_mt_detect (void)
     vls_mt_add ();
 }
 
-#define vls_mt_guard(_vls, _op)                                                \
-  int _locks_acq = 0;                                                  \
-  if (vls_mt_wrk_supported ())                                         \
-    {                                                                  \
-      if (PREDICT_FALSE (_vls                                          \
-           && ((vcl_locked_session_t *)_vls)->worker_index !=          \
-               vcl_get_worker_index ()))                               \
-         vls_mt_session_migrate (_vls);                                \
-    }                                                                  \
-  else                                                                 \
-    {                                                                  \
-      if (PREDICT_FALSE (vlsl->vls_mt_n_threads > 1))                  \
-        vls_mt_acq_locks (_vls, _op, &_locks_acq);                     \
-    }                                                                  \
+#define vls_mt_guard(_vls, _op)                                               \
+  int _locks_acq = 0;                                                         \
+  if (vls_mt_wrk_supported ())                                                \
+    {                                                                         \
+      if (PREDICT_FALSE (_vls &&                                              \
+                        ((vcl_locked_session_t *) _vls)->worker_index !=     \
+                          vcl_get_worker_index ()))                          \
+       {                                                                     \
+         _vls = vls_mt_session_migrate (_vls);                               \
+         if (PREDICT_FALSE (!_vls))                                          \
+           return VPPCOM_EBADFD;                                             \
+       }                                                                     \
+    }                                                                         \
+  else                                                                        \
+    {                                                                         \
+      if (PREDICT_FALSE (vlsl->vls_mt_n_threads > 1))                         \
+       vls_mt_acq_locks (_vls, _op, &_locks_acq);                            \
+    }
 
 #define vls_mt_unguard()                                               \
   if (PREDICT_FALSE (_locks_acq))                                      \
@@ -1034,7 +1114,11 @@ vls_attr (vls_handle_t vlsh, uint32_t op, void *buffer, uint32_t * buflen)
   if (!(vls = vls_get_w_dlock (vlsh)))
     return VPPCOM_EBADFD;
   if (vls_mt_session_should_migrate (vls))
-    vls_mt_session_migrate (vls);
+    {
+      vls = vls_mt_session_migrate (vls);
+      if (PREDICT_FALSE (!vls))
+       return VPPCOM_EBADFD;
+    }
   rv = vppcom_session_attr (vls_to_sh_tu (vls), op, buffer, buflen);
   vls_get_and_unlock (vlsh);
   return rv;
@@ -1159,9 +1243,10 @@ vls_create (uint8_t proto, uint8_t is_nonblocking)
 {
   vcl_session_handle_t sh;
   vls_handle_t vlsh;
+  vcl_locked_session_t *vls = NULL;
 
   vls_mt_detect ();
-  vls_mt_guard (0, VLS_MT_OP_SPOOL);
+  vls_mt_guard (vls, VLS_MT_OP_SPOOL);
   sh = vppcom_session_create (proto, is_nonblocking);
   vls_mt_unguard ();
   if (sh == INVALID_SESSION_ID)
@@ -1228,6 +1313,24 @@ vls_close (vls_handle_t vlsh)
   return rv;
 }
 
+int
+vls_shutdown (vls_handle_t vlsh, int how)
+{
+  vcl_locked_session_t *vls;
+  int rv;
+
+  vls_mt_detect ();
+  if (!(vls = vls_get_w_dlock (vlsh)))
+    return VPPCOM_EBADFD;
+
+  vls_mt_guard (vls, VLS_MT_OP_SPOOL);
+  rv = vppcom_session_shutdown (vls_to_sh (vls), how);
+  vls_mt_unguard ();
+  vls_get_and_unlock (vlsh);
+
+  return rv;
+}
+
 vls_handle_t
 vls_epoll_create (void)
 {
@@ -1250,16 +1353,9 @@ vls_epoll_create (void)
 static void
 vls_epoll_ctl_mp_checks (vcl_locked_session_t * vls, int op)
 {
-  if (vcl_n_workers () <= 1)
-    {
-      vlsl->epoll_mp_check = 1;
-      return;
-    }
-
-  if (op == EPOLL_CTL_MOD)
+  if (vcl_n_workers () <= 1 || op == EPOLL_CTL_MOD)
     return;
 
-  vlsl->epoll_mp_check = 1;
   vls_mp_checks (vls, op == EPOLL_CTL_ADD);
 }
 
@@ -1274,19 +1370,20 @@ vls_epoll_ctl (vls_handle_t ep_vlsh, int op, vls_handle_t vlsh,
   vls_mt_detect ();
   vls_mt_table_rlock ();
   ep_vls = vls_get_and_lock (ep_vlsh);
-  vls = vls_get_and_lock (vlsh);
 
   if (vls_mt_session_should_migrate (ep_vls))
-    vls_mt_session_migrate (ep_vls);
+    {
+      ep_vls = vls_mt_session_migrate (ep_vls);
+      if (PREDICT_FALSE (!ep_vls))
+       return VPPCOM_EBADFD;
+    }
 
   ep_sh = vls_to_sh (ep_vls);
+  vls = vls_get_and_lock (vlsh);
   sh = vls_to_sh (vls);
 
-  if (PREDICT_FALSE (!vlsl->epoll_mp_check))
-    vls_epoll_ctl_mp_checks (vls, op);
-
+  vls_epoll_ctl_mp_checks (vls, op);
   vls_mt_table_runlock ();
-
   rv = vppcom_epoll_ctl (ep_sh, op, sh, event);
 
   vls_mt_table_rlock ();
@@ -1302,13 +1399,13 @@ int
 vls_epoll_wait (vls_handle_t ep_vlsh, struct epoll_event *events,
                int maxevents, double wait_for_time)
 {
-  vcl_locked_session_t *vls;
+  vcl_locked_session_t *vls, *vls_tmp = NULL;
   int rv;
 
   vls_mt_detect ();
   if (!(vls = vls_get_w_dlock (ep_vlsh)))
     return VPPCOM_EBADFD;
-  vls_mt_guard (0, VLS_MT_OP_XPOLL);
+  vls_mt_guard (vls_tmp, VLS_MT_OP_XPOLL);
   rv = vppcom_epoll_wait (vls_to_sh_tu (vls), events, maxevents,
                          wait_for_time);
   vls_mt_unguard ();
@@ -1337,14 +1434,14 @@ vls_select_mp_checks (vcl_si_set * read_map)
   wrk = vcl_worker_get_current ();
 
   /* *INDENT-OFF* */
-  clib_bitmap_foreach (si, read_map, ({
+  clib_bitmap_foreach (si, read_map)  {
     s = vcl_session_get (wrk, si);
     if (s->session_state == VCL_STATE_LISTEN)
       {
        vls = vls_get (vls_session_index_to_vlsh (si));
        vls_mp_checks (vls, 1 /* is_add */);
       }
-  }));
+  }
   /* *INDENT-ON* */
 }
 
@@ -1353,9 +1450,10 @@ vls_select (int n_bits, vcl_si_set * read_map, vcl_si_set * write_map,
            vcl_si_set * except_map, double wait_for_time)
 {
   int rv;
+  vcl_locked_session_t *vls = NULL;
 
   vls_mt_detect ();
-  vls_mt_guard (0, VLS_MT_OP_XPOLL);
+  vls_mt_guard (vls, VLS_MT_OP_XPOLL);
   if (PREDICT_FALSE (!vlsl->select_mp_check))
     vls_select_mp_checks (read_map);
   rv = vppcom_select (n_bits, read_map, write_map, except_map, wait_for_time);
@@ -1377,11 +1475,11 @@ vls_unshare_vcl_worker_sessions (vcl_worker_t * wrk)
   is_current = current_wrk == wrk->wrk_index;
 
   /* *INDENT-OFF* */
-  pool_foreach (s, wrk->sessions, ({
+  pool_foreach (s, wrk->sessions)  {
     vls = vls_get (vls_si_wi_to_vlsh (s->session_index, wrk->wrk_index));
     if (vls && (is_current || vls_is_shared_by_wrk (vls, current_wrk)))
       vls_unshare_session (vls, wrk);
-  }));
+  }
   /* *INDENT-ON* */
 }
 
@@ -1470,6 +1568,11 @@ static void
 vls_incercept_sigchld ()
 {
   struct sigaction sa;
+  if (old_sa.sa_sigaction)
+    {
+      VDBG (0, "have intercepted sigchld");
+      return;
+    }
   clib_memset (&sa, 0, sizeof (sa));
   sa.sa_sigaction = vls_intercept_sigchld_handler;
   sa.sa_flags = SA_SIGINFO;
@@ -1523,7 +1626,6 @@ vls_app_fork_child_handler (void)
   vlsl->vls_mt_n_threads = 0;
   vlsl->vls_wrk_index = vcl_get_worker_index ();
   vlsl->select_mp_check = 0;
-  vlsl->epoll_mp_check = 0;
   vls_mt_locks_init ();
 
   VDBG (0, "forked child main worker initialized");
@@ -1557,24 +1659,33 @@ vls_clone_and_share_rpc_handler (void *args)
   vcl_worker_t *vcl_wrk = vcl_worker_get_current (), *dst_vcl_wrk;
   vcl_session_t *s, *dst_s;
 
-  vls = vls_session_get (wrk, msg->vls_index);
-
-  if (!vls_mt_wrk_supported ())
-    vls_init_share_session (wrk, vls);
+  VDBG (1, "process session clone of worker (session): %u (%u) -> %u (%u)",
+       vcl_wrk->wrk_index, msg->session_index, msg->origin_vcl_wrk,
+       msg->origin_session_index);
 
-  s = vcl_session_get (vcl_wrk, msg->session_index);
-  dst_wrk = vls_worker_get (msg->origin_vls_wrk);
+  /* VCL locked session can't been protected, so DONT touch it.
+   * VCL session may been free, check it.
+   */
   dst_vcl_wrk = vcl_worker_get (msg->origin_vcl_wrk);
-  dst_vls = vls_session_get (dst_wrk, msg->origin_vls_index);
-  dst_vls->shared_data_index = vls->shared_data_index;
+  s = vcl_session_get (vcl_wrk, msg->session_index);
+  if (PREDICT_FALSE (!s))
+    {
+      dst_vcl_wrk->rpc_done = VLS_RPC_STATE_SESSION_NOT_EXIST;
+      return;
+    }
+
+  if (!vls_mt_wrk_supported ())
+    {
+      vls = vls_session_get (wrk, msg->vls_index);
+      vls_init_share_session (wrk, vls);
+      dst_wrk = vls_worker_get (msg->origin_vls_wrk);
+      dst_vls = vls_session_get (dst_wrk, msg->origin_vls_index);
+      dst_vls->shared_data_index = vls->shared_data_index;
+    }
   dst_s = vcl_session_get (dst_vcl_wrk, msg->origin_session_index);
   clib_memcpy (dst_s, s, sizeof (*s));
 
-  dst_vcl_wrk->rpc_done = 1;
-
-  VDBG (1, "proces session clone of worker (session): %u (%u) -> %u (%u)",
-       vcl_wrk->wrk_index, msg->session_index, dst_vcl_wrk->wrk_index,
-       msg->origin_session_index);
+  dst_vcl_wrk->rpc_done = VLS_RPC_STATE_SUCCESS;
 }
 
 static void
@@ -1582,14 +1693,14 @@ vls_session_cleanup_rpc_handler (void *args)
 {
   vls_sess_cleanup_msg_t *msg = (vls_sess_cleanup_msg_t *) args;
   vcl_worker_t *wrk = vcl_worker_get_current ();
-  vcl_worker_t *dst_wrk = vcl_worker_get (msg->origin_vcl_wrk);
-
-  vppcom_session_close (vcl_session_handle_from_index (msg->session_index));
+  vls_worker_t *vls_wrk = vls_worker_get_current ();
+  vcl_session_handle_t sh = vcl_session_handle_from_index (msg->session_index);
 
-  dst_wrk->rpc_done = 1;
+  VDBG (1, "process session cleanup of worker (session): %u (%u) from %u ()",
+       wrk->wrk_index, msg->session_index, msg->origin_vcl_wrk);
 
-  VDBG (1, "proces session cleanup of worker (session): %u (%u) from %u ()",
-       wrk->wrk_index, msg->session_index, dst_wrk->wrk_index);
+  vppcom_session_close (sh);
+  vls_sh_to_vlsh_table_del (vls_wrk, sh);
 }
 
 static void
@@ -1610,34 +1721,42 @@ vls_rpc_handler (void *args)
 }
 
 void
-vls_send_clone_and_share_rpc (vcl_worker_t * wrk,
-                             vcl_locked_session_t * vls, u32 session_index,
-                             u32 vls_wrk_index, u32 dst_wrk_index,
-                             u32 dst_vls_index, u32 dst_session_index)
+vls_send_clone_and_share_rpc (vcl_worker_t *wrk, u32 origin_vls_index,
+                             u32 session_index, u32 vls_wrk_index,
+                             u32 dst_wrk_index, u32 dst_vls_index,
+                             u32 dst_session_index)
 {
   u8 data[sizeof (u8) + sizeof (vls_clone_and_share_msg_t)];
   vls_clone_and_share_msg_t *msg;
   vls_rpc_msg_t *rpc;
   int ret;
+  f64 timeout = clib_time_now (&wrk->clib_time) + VLS_WORKER_RPC_TIMEOUT;
 
   rpc = (vls_rpc_msg_t *) & data;
   rpc->type = VLS_RPC_CLONE_AND_SHARE;
   msg = (vls_clone_and_share_msg_t *) & rpc->data;
   msg->origin_vls_wrk = vls_wrk_index;
-  msg->origin_vls_index = vls->vls_index;
+  msg->origin_vls_index = origin_vls_index;
   msg->origin_vcl_wrk = wrk->wrk_index;
   msg->origin_session_index = session_index;
   msg->vls_index = dst_vls_index;
   msg->session_index = dst_session_index;
 
-  wrk->rpc_done = 0;
+  /* Try lock and handle rpcs if two threads send each other
+   * clone requests at the same time.
+   */
+  wrk->rpc_done = VLS_RPC_STATE_INIT;
+  while (!clib_spinlock_trylock (&vlsm->worker_rpc_lock))
+    vcl_flush_mq_events ();
   ret = vcl_send_worker_rpc (dst_wrk_index, rpc, sizeof (data));
 
   VDBG (1, "send session clone to wrk (session): %u (%u) -> %u (%u), ret=%d",
        dst_wrk_index, msg->session_index, msg->origin_vcl_wrk,
        msg->origin_session_index, ret);
-  while (!ret && !wrk->rpc_done)
+  while (!ret && wrk->rpc_done == VLS_RPC_STATE_INIT &&
+        clib_time_now (&wrk->clib_time) < timeout)
     ;
+  clib_spinlock_unlock (&vlsm->worker_rpc_lock);
 }
 
 void
@@ -1655,13 +1774,10 @@ vls_send_session_cleanup_rpc (vcl_worker_t * wrk,
   msg->origin_vcl_wrk = wrk->wrk_index;
   msg->session_index = dst_session_index;
 
-  wrk->rpc_done = 0;
   ret = vcl_send_worker_rpc (dst_wrk_index, rpc, sizeof (data));
 
   VDBG (1, "send session cleanup to wrk (session): %u (%u) from %u, ret=%d",
        dst_wrk_index, msg->session_index, msg->origin_vcl_wrk, ret);
-  while (!ret && !wrk->rpc_done)
-    ;
 }
 
 int
@@ -1676,6 +1792,7 @@ vls_app_create (char *app_name)
   clib_memset (vlsm, 0, sizeof (*vlsm));
   clib_rwlock_init (&vlsm->vls_table_lock);
   clib_rwlock_init (&vlsm->shared_data_lock);
+  clib_spinlock_init (&vlsm->worker_rpc_lock);
   pool_alloc (vlsm->workers, vcm->cfg.max_workers);
 
   pthread_atfork (vls_app_pre_fork, vls_app_fork_parent_handler,
@@ -1712,11 +1829,7 @@ vls_use_real_epoll (void)
 void
 vls_register_vcl_worker (void)
 {
-  if (vppcom_worker_register () != VPPCOM_OK)
-    {
-      VERR ("failed to register worker");
-      return;
-    }
+  vls_mt_add ();
 }
 
 /*