vcl: grab wrk create lock sooner

Type: fix

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I0faeef20c57486564122e39f01f31c8c45f38014
(cherry picked from commit 94fef3e67662c6a92e32164d8db6fcf4bc83e79e)

.gitreview

@@ -2,3 +2,4 @@
 host=gerrit.fd.io
 port=29418
 project=vpp
+defaultbranch=stable/2110

src/vcl/vcl_private.c

@@ -167,16 +167,19 @@ vcl_worker_alloc_and_init ()
   if (vcl_get_worker_index () != ~0)
     return 0;
 
+  /* Grab lock before selecting mem thread index */
+  clib_spinlock_lock (&vcm->workers_lock);
+
   /* Use separate heap map entry for worker */
   clib_mem_set_thread_index ();
 
   if (pool_elts (vcm->workers) == vcm->cfg.max_workers)
     {
       VDBG (0, "max-workers %u limit reached", vcm->cfg.max_workers);
-      return 0;
+      wrk = 0;
+      goto done;
     }
 
-  clib_spinlock_lock (&vcm->workers_lock);
   wrk = vcl_worker_alloc ();
   vcl_set_worker_index (wrk->wrk_index);
   wrk->thread_id = pthread_self ();
@@ -203,9 +206,9 @@ vcl_worker_alloc_and_init ()
   vec_reset_length (wrk->mq_msg_vector);
   vec_validate (wrk->unhandled_evts_vector, 128);
   vec_reset_length (wrk->unhandled_evts_vector);
-  clib_spinlock_unlock (&vcm->workers_lock);
 
 done:
+  clib_spinlock_unlock (&vcm->workers_lock);
   return wrk;
 }