Fix Python epoll1 Fork Support

src/core/lib/event_engine/posix_engine/ev_epoll1_linux.cc

@@ -375,7 +375,10 @@ void Epoll1Poller::Shutdown() {
 }
 
 void Epoll1Poller::Close() {
-  if (closed_) return;
+  {
+    grpc_core::MutexLock lock(&mu_);
+    if (closed_) return;
+  }
 
   if (g_epoll_set_.epfd >= 0) {
     close(g_epoll_set_.epfd);
@@ -389,8 +392,8 @@ void Epoll1Poller::Close() {
       free_epoll1_handles_list_.pop_front();
       delete handle;
     }
+    closed_ = true;
   }
-  closed_ = true;
 }
 
 Epoll1Poller::~Epoll1Poller() { Close(); }
@@ -577,8 +580,10 @@ Epoll1Poller* MakeEpoll1Poller(Scheduler* scheduler) {
 
 void Epoll1Poller::PrepareFork() { Kick(); }
 
+// TODO(vigneshbabu): implement
 void Epoll1Poller::PostforkParent() {}
 
+// TODO(vigneshbabu): implement
 void Epoll1Poller::PostforkChild() {}
 
 }  // namespace experimental

src/core/lib/event_engine/posix_engine/ev_epoll1_linux.h

@@ -47,8 +47,7 @@ namespace experimental {
 class Epoll1EventHandle;
 
 // Definition of epoll1 based poller.
-class Epoll1Poller : public PosixEventPoller,
-                     public grpc_event_engine::experimental::Forkable {
+class Epoll1Poller : public PosixEventPoller, public Forkable {
  public:
   explicit Epoll1Poller(Scheduler* scheduler);
   EventHandle* CreateHandle(int fd, absl::string_view name,

src/core/lib/gprpp/fork.cc

@@ -199,7 +199,9 @@ void Fork::SetResetChildPollingEngineFunc(
     reset_child_polling_engine_->emplace_back(reset_child_polling_engine);
   }
 }
-std::vector<Fork::child_postfork_func> Fork::GetResetChildPollingEngineFunc() {
+
+const std::vector<Fork::child_postfork_func>&
+Fork::GetResetChildPollingEngineFunc() {
   return *reset_child_polling_engine_;
 }
 

src/core/lib/gprpp/fork.h

@@ -59,7 +59,8 @@ class Fork {
   // reset the polling engine's internal state.
   static void SetResetChildPollingEngineFunc(
       child_postfork_func reset_child_polling_engine);
-  static std::vector<child_postfork_func> GetResetChildPollingEngineFunc();
+  static const std::vector<child_postfork_func>&
+  GetResetChildPollingEngineFunc();
 
   // Check if there is a single active ExecCtx
   // (the one used to invoke this function).  If there are more,

src/core/lib/iomgr/fork_posix.cc

@@ -100,7 +100,7 @@ void grpc_postfork_child() {
   if (!skipped_handler) {
     grpc_core::Fork::AllowExecCtx();
     grpc_core::ExecCtx exec_ctx;
-    for (auto reset_polling_engine :
+    for (auto* reset_polling_engine :
          grpc_core::Fork::GetResetChildPollingEngineFunc()) {
       if (reset_polling_engine != nullptr) {
         reset_polling_engine();