Merge pull request #15879 from hcaseyal/client_auth_allocation

Remove allocation in client auth filter and use call arena instead

src/core/lib/security/context/security_context.cc

@@ -50,7 +50,7 @@ grpc_call_error grpc_call_set_credentials(grpc_call* call,
   ctx = static_cast<grpc_client_security_context*>(
       grpc_call_context_get(call, GRPC_CONTEXT_SECURITY));
   if (ctx == nullptr) {
-    ctx = grpc_client_security_context_create();
+    ctx = grpc_client_security_context_create(grpc_call_get_arena(call));
     ctx->creds = grpc_call_credentials_ref(creds);
     grpc_call_context_set(call, GRPC_CONTEXT_SECURITY, ctx,
                           grpc_client_security_context_destroy);
@@ -82,9 +82,10 @@ void grpc_auth_context_release(grpc_auth_context* context) {
 
 /* --- grpc_client_security_context --- */
 
-grpc_client_security_context* grpc_client_security_context_create(void) {
+grpc_client_security_context* grpc_client_security_context_create(
+    gpr_arena* arena) {
   return static_cast<grpc_client_security_context*>(
-      gpr_zalloc(sizeof(grpc_client_security_context)));
+      gpr_arena_alloc(arena, sizeof(grpc_client_security_context)));
 }
 
 void grpc_client_security_context_destroy(void* ctx) {
@@ -96,7 +97,6 @@ void grpc_client_security_context_destroy(void* ctx) {
   if (c->extension.instance != nullptr && c->extension.destroy != nullptr) {
     c->extension.destroy(c->extension.instance);
   }
-  gpr_free(ctx);
 }
 
 /* --- grpc_server_security_context --- */

src/core/lib/security/context/security_context.h

@@ -91,7 +91,8 @@ typedef struct {
   grpc_security_context_extension extension;
 } grpc_client_security_context;
 
-grpc_client_security_context* grpc_client_security_context_create(void);
+grpc_client_security_context* grpc_client_security_context_create(
+    gpr_arena* arena);
 void grpc_client_security_context_destroy(void* ctx);
 
 /* --- grpc_server_security_context ---

src/core/lib/security/transport/client_auth_filter.cc

@@ -42,6 +42,7 @@
 namespace {
 /* We can have a per-call credentials. */
 struct call_data {
+  gpr_arena* arena;
   grpc_call_stack* owning_call;
   grpc_call_combiner* call_combiner;
   grpc_call_credentials* creds;
@@ -276,10 +277,12 @@ static void auth_start_transport_stream_op_batch(
   channel_data* chand = static_cast<channel_data*>(elem->channel_data);
 
   if (!batch->cancel_stream) {
+    // TODO(hcaseyal): move this to init_call_elem once issue #15927 is
+    // resolved.
     GPR_ASSERT(batch->payload->context != nullptr);
     if (batch->payload->context[GRPC_CONTEXT_SECURITY].value == nullptr) {
       batch->payload->context[GRPC_CONTEXT_SECURITY].value =
-          grpc_client_security_context_create();
+          grpc_client_security_context_create(calld->arena);
       batch->payload->context[GRPC_CONTEXT_SECURITY].destroy =
           grpc_client_security_context_destroy;
     }
@@ -335,6 +338,7 @@ static void auth_start_transport_stream_op_batch(
 static grpc_error* init_call_elem(grpc_call_element* elem,
                                   const grpc_call_element_args* args) {
   call_data* calld = static_cast<call_data*>(elem->call_data);
+  calld->arena = args->arena;
   calld->owning_call = args->call_stack;
   calld->call_combiner = args->call_combiner;
   calld->host = grpc_empty_slice();