diff --git a/src/core/ext/filters/client_channel/subchannel_index.cc b/src/core/ext/filters/client_channel/subchannel_index.cc
index 1c23a6c4be4..aa8441f17b0 100644
--- a/src/core/ext/filters/client_channel/subchannel_index.cc
+++ b/src/core/ext/filters/client_channel/subchannel_index.cc
@@ -91,7 +91,7 @@ void grpc_subchannel_key_destroy(grpc_subchannel_key* k) {
   gpr_free(k);
 }
 
-static void sck_avl_destroy(void* p, void* user_data) {
+static void sck_avl_destroy(void* p, void* unused) {
   grpc_subchannel_key_destroy(static_cast<grpc_subchannel_key*>(p));
 }
 
@@ -104,7 +104,7 @@ static long sck_avl_compare(void* a, void* b, void* unused) {
                                      static_cast<grpc_subchannel_key*>(b));
 }
 
-static void scv_avl_destroy(void* p, void* user_data) {
+static void scv_avl_destroy(void* p, void* unused) {
   GRPC_SUBCHANNEL_WEAK_UNREF((grpc_subchannel*)p, "subchannel_index");
 }
 
@@ -137,7 +137,7 @@ void grpc_subchannel_index_shutdown(void) {
 void grpc_subchannel_index_unref(void) {
   if (gpr_unref(&g_refcount)) {
     gpr_mu_destroy(&g_mu);
-    grpc_avl_unref(g_subchannel_index, grpc_core::ExecCtx::Get());
+    grpc_avl_unref(g_subchannel_index, nullptr);
   }
 }
 
@@ -147,13 +147,12 @@ grpc_subchannel* grpc_subchannel_index_find(grpc_subchannel_key* key) {
   // Lock, and take a reference to the subchannel index.
   // We don't need to do the search under a lock as avl's are immutable.
   gpr_mu_lock(&g_mu);
-  grpc_avl index = grpc_avl_ref(g_subchannel_index, grpc_core::ExecCtx::Get());
+  grpc_avl index = grpc_avl_ref(g_subchannel_index, nullptr);
   gpr_mu_unlock(&g_mu);
 
   grpc_subchannel* c = GRPC_SUBCHANNEL_REF_FROM_WEAK_REF(
-      (grpc_subchannel*)grpc_avl_get(index, key, grpc_core::ExecCtx::Get()),
-      "index_find");
-  grpc_avl_unref(index, grpc_core::ExecCtx::Get());
+      (grpc_subchannel*)grpc_avl_get(index, key, nullptr), "index_find");
+  grpc_avl_unref(index, nullptr);
 
   return c;
 }
@@ -169,13 +168,11 @@ grpc_subchannel* grpc_subchannel_index_register(grpc_subchannel_key* key,
     // Compare and swap loop:
     // - take a reference to the current index
     gpr_mu_lock(&g_mu);
-    grpc_avl index =
-        grpc_avl_ref(g_subchannel_index, grpc_core::ExecCtx::Get());
+    grpc_avl index = grpc_avl_ref(g_subchannel_index, nullptr);
     gpr_mu_unlock(&g_mu);
 
     // - Check to see if a subchannel already exists
-    c = static_cast<grpc_subchannel*>(
-        grpc_avl_get(index, key, grpc_core::ExecCtx::Get()));
+    c = static_cast<grpc_subchannel*>(grpc_avl_get(index, key, nullptr));
     if (c != nullptr) {
       c = GRPC_SUBCHANNEL_REF_FROM_WEAK_REF(c, "index_register");
     }
@@ -184,11 +181,9 @@ grpc_subchannel* grpc_subchannel_index_register(grpc_subchannel_key* key,
       need_to_unref_constructed = true;
     } else {
       // no -> update the avl and compare/swap
-      grpc_avl updated =
-          grpc_avl_add(grpc_avl_ref(index, grpc_core::ExecCtx::Get()),
-                       subchannel_key_copy(key),
-                       GRPC_SUBCHANNEL_WEAK_REF(constructed, "index_register"),
-                       grpc_core::ExecCtx::Get());
+      grpc_avl updated = grpc_avl_add(
+          grpc_avl_ref(index, nullptr), subchannel_key_copy(key),
+          GRPC_SUBCHANNEL_WEAK_REF(constructed, "index_register"), nullptr);
 
       // it may happen (but it's expected to be unlikely)
       // that some other thread has changed the index:
@@ -200,9 +195,9 @@ grpc_subchannel* grpc_subchannel_index_register(grpc_subchannel_key* key,
       }
       gpr_mu_unlock(&g_mu);
 
-      grpc_avl_unref(updated, grpc_core::ExecCtx::Get());
+      grpc_avl_unref(updated, nullptr);
     }
-    grpc_avl_unref(index, grpc_core::ExecCtx::Get());
+    grpc_avl_unref(index, nullptr);
   }
 
   if (need_to_unref_constructed) {
@@ -219,24 +214,22 @@ void grpc_subchannel_index_unregister(grpc_subchannel_key* key,
     // Compare and swap loop:
     // - take a reference to the current index
     gpr_mu_lock(&g_mu);
-    grpc_avl index =
-        grpc_avl_ref(g_subchannel_index, grpc_core::ExecCtx::Get());
+    grpc_avl index = grpc_avl_ref(g_subchannel_index, nullptr);
     gpr_mu_unlock(&g_mu);
 
     // Check to see if this key still refers to the previously
     // registered subchannel
-    grpc_subchannel* c = static_cast<grpc_subchannel*>(
-        grpc_avl_get(index, key, grpc_core::ExecCtx::Get()));
+    grpc_subchannel* c =
+        static_cast<grpc_subchannel*>(grpc_avl_get(index, key, nullptr));
     if (c != constructed) {
-      grpc_avl_unref(index, grpc_core::ExecCtx::Get());
+      grpc_avl_unref(index, nullptr);
       break;
     }
 
     // compare and swap the update (some other thread may have
     // mutated the index behind us)
     grpc_avl updated =
-        grpc_avl_remove(grpc_avl_ref(index, grpc_core::ExecCtx::Get()), key,
-                        grpc_core::ExecCtx::Get());
+        grpc_avl_remove(grpc_avl_ref(index, nullptr), key, nullptr);
 
     gpr_mu_lock(&g_mu);
     if (index.root == g_subchannel_index.root) {
@@ -245,8 +238,8 @@ void grpc_subchannel_index_unregister(grpc_subchannel_key* key,
     }
     gpr_mu_unlock(&g_mu);
 
-    grpc_avl_unref(updated, grpc_core::ExecCtx::Get());
-    grpc_avl_unref(index, grpc_core::ExecCtx::Get());
+    grpc_avl_unref(updated, nullptr);
+    grpc_avl_unref(index, nullptr);
   }
 }