Removing instances of exec_ctx being passed around in functions in

src/core. exec_ctx is now a thread_local pointer of type ExecCtx instead of
grpc_exec_ctx which is initialized whenever ExecCtx is instantiated. ExecCtx
also keeps track of the previous exec_ctx so that nesting of exec_ctx is
allowed. This means that there is only one exec_ctx being used at any
time. Also, grpc_exec_ctx_finish is called in the destructor of the
object, and the previous exec_ctx is restored to avoid breaking current
functionality. The code still explicitly calls grpc_exec_ctx_finish
because removing all such instances causes the code to break.

1 files changed, 9 insertions, 14 deletions

diff --git a/src/core/ext/filters/client_channel/client_channel_factory.cc b/src/core/ext/filters/client_channel/client_channel_factory.cc
index 57eac8f875..60c95d7dc9 100644
--- a/src/core/ext/filters/client_channel/client_channel_factory.cc
+++ b/src/core/ext/filters/client_channel/client_channel_factory.cc
@@ -23,23 +23,19 @@ void grpc_client_channel_factory_ref(grpc_client_channel_factory* factory) {
   factory->vtable->ref(factory);
 }
 
-void grpc_client_channel_factory_unref(grpc_exec_ctx* exec_ctx,
-                                       grpc_client_channel_factory* factory) {
-  factory->vtable->unref(exec_ctx, factory);
+void grpc_client_channel_factory_unref(grpc_client_channel_factory* factory) {
+  factory->vtable->unref(factory);
 }
 
 grpc_subchannel* grpc_client_channel_factory_create_subchannel(
-    grpc_exec_ctx* exec_ctx, grpc_client_channel_factory* factory,
-    const grpc_subchannel_args* args) {
-  return factory->vtable->create_subchannel(exec_ctx, factory, args);
+    grpc_client_channel_factory* factory, const grpc_subchannel_args* args) {
+  return factory->vtable->create_subchannel(factory, args);
 }
 
 grpc_channel* grpc_client_channel_factory_create_channel(
-    grpc_exec_ctx* exec_ctx, grpc_client_channel_factory* factory,
-    const char* target, grpc_client_channel_type type,
-    const grpc_channel_args* args) {
-  return factory->vtable->create_client_channel(exec_ctx, factory, target, type,
-                                                args);
+    grpc_client_channel_factory* factory, const char* target,
+    grpc_client_channel_type type, const grpc_channel_args* args) {
+  return factory->vtable->create_client_channel(factory, target, type, args);
 }
 
 static void* factory_arg_copy(void* factory) {
@@ -47,9 +43,8 @@ static void* factory_arg_copy(void* factory) {
   return factory;
 }
 
-static void factory_arg_destroy(grpc_exec_ctx* exec_ctx, void* factory) {
-  grpc_client_channel_factory_unref(exec_ctx,
-                                    (grpc_client_channel_factory*)factory);
+static void factory_arg_destroy(void* factory) {
+  grpc_client_channel_factory_unref((grpc_client_channel_factory*)factory);
 }
 
 static int factory_arg_cmp(void* factory1, void* factory2) {