Merge branch 'master' of github.com:grpc/grpc into grpclb_api

2 files changed, 19 insertions, 8 deletions

diff --git a/src/core/client_config/lb_policies/pick_first.c b/src/core/client_config/lb_policies/pick_first.c
index e6ddb1a11f..5b10600ab5 100644
--- a/src/core/client_config/lb_policies/pick_first.c
+++ b/src/core/client_config/lb_policies/pick_first.c
@@ -76,7 +76,7 @@ typedef struct {
 } pick_first_lb_policy;
 
 #define GET_SELECTED(p) \
-  ((grpc_connected_subchannel *)gpr_atm_no_barrier_load(&(p)->selected))
+  ((grpc_connected_subchannel *)gpr_atm_acq_load(&(p)->selected))
 
 void pf_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
@@ -268,10 +268,10 @@ static void pf_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
         selected =
             grpc_subchannel_get_connected_subchannel(selected_subchannel);
         GPR_ASSERT(selected != NULL);
-        gpr_atm_no_barrier_store(&p->selected, (gpr_atm)selected);
         GRPC_CONNECTED_SUBCHANNEL_REF(selected, "picked_first");
         /* drop the pick list: we are connected now */
         GRPC_LB_POLICY_WEAK_REF(&p->base, "destroy_subchannels");
+        gpr_atm_rel_store(&p->selected, (gpr_atm)selected);
         grpc_exec_ctx_enqueue(exec_ctx,
                               grpc_closure_create(destroy_subchannels, p), 1);
         /* update any calls that were waiting for a pick */
diff --git a/src/core/client_config/subchannel.c b/src/core/client_config/subchannel.c
index 2992da8b79..fccc1dda54 100644
--- a/src/core/client_config/subchannel.c
+++ b/src/core/client_config/subchannel.c
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -284,9 +284,13 @@ grpc_subchannel *grpc_subchannel_create(grpc_connector *connector,
   c->connector = connector;
   grpc_connector_ref(c->connector);
   c->num_filters = args->filter_count;
-  c->filters = gpr_malloc(sizeof(grpc_channel_filter *) * c->num_filters);
-  memcpy((void *)c->filters, args->filters,
-         sizeof(grpc_channel_filter *) * c->num_filters);
+  if (c->num_filters > 0) {
+    c->filters = gpr_malloc(sizeof(grpc_channel_filter *) * c->num_filters);
+    memcpy((void *)c->filters, args->filters,
+           sizeof(grpc_channel_filter *) * c->num_filters);
+  } else {
+    c->filters = NULL;
+  }
   c->addr = gpr_malloc(args->addr_len);
   memcpy(c->addr, args->addr, args->addr_len);
   grpc_pollset_set_init(&c->pollset_set);
@@ -483,7 +487,9 @@ static void publish_transport(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
   /* build final filter list */
   num_filters = c->num_filters + c->connecting_result.num_filters + 1;
   filters = gpr_malloc(sizeof(*filters) * num_filters);
-  memcpy((void *)filters, c->filters, sizeof(*filters) * c->num_filters);
+  if (c->num_filters > 0) {
+    memcpy((void *)filters, c->filters, sizeof(*filters) * c->num_filters);
+  }
   memcpy((void *)(filters + c->num_filters), c->connecting_result.filters,
          sizeof(*filters) * c->connecting_result.num_filters);
   filters[num_filters - 1] = &grpc_connected_channel_filter;
@@ -519,7 +525,12 @@ static void publish_transport(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
   }
 
   /* publish */
-  GPR_ASSERT(gpr_atm_no_barrier_cas(&c->connected_subchannel, 0, (gpr_atm)con));
+  /* TODO(ctiller): this full barrier seems to clear up a TSAN failure.
+                    I'd have expected the rel_cas below to be enough, but
+                    seemingly it's not.
+                    Re-evaluate if we really need this. */
+  gpr_atm_full_barrier();
+  GPR_ASSERT(gpr_atm_rel_cas(&c->connected_subchannel, 0, (gpr_atm)con));
   c->connecting = 0;
 
   /* setup subchannel watching connected subchannel for changes; subchannel ref