Cleanup poll-cv setup

src/core/lib/iomgr/ev_epoll_linux.c

@@ -1892,7 +1892,7 @@ const grpc_event_engine_vtable *grpc_init_epoll_linux(void) {
     return NULL;
   }
 
-  if (!grpc_has_wakeup_fd) {
+  if (!grpc_has_wakeup_fd()) {
     return NULL;
   }
 

src/core/lib/iomgr/ev_poll_cv_posix.c

@@ -255,21 +255,12 @@ static void shutdown_engine(void) {
 }
 
 const grpc_event_engine_vtable* grpc_init_poll_cv_posix(void) {
-  int has_wakeup_fd = grpc_has_wakeup_fd;
-  int allow_specialized_wakeup_fd = grpc_allow_specialized_wakeup_fd;
-  int allow_pipe_wakeup_fd = grpc_allow_pipe_wakeup_fd;
   grpc_global_cv_fd_table_init();
-  grpc_allow_specialized_wakeup_fd = 0;
-  grpc_allow_pipe_wakeup_fd = 0;
-  grpc_wakeup_fd_global_init();
-  grpc_has_wakeup_fd = 1;
+  grpc_enable_cv_wakeup_fds(1);
   ev_poll_vtable = grpc_init_poll_posix();
   if (!ev_poll_vtable) {
     grpc_global_cv_fd_table_shutdown();
-    grpc_has_wakeup_fd = has_wakeup_fd;
-    grpc_allow_specialized_wakeup_fd = allow_specialized_wakeup_fd;
-    grpc_allow_pipe_wakeup_fd = allow_pipe_wakeup_fd;
-    grpc_global_cv_fd_table_init();
+    grpc_enable_cv_wakeup_fds(0);
     return NULL;
   }
   vtable = *ev_poll_vtable;

src/core/lib/iomgr/ev_poll_posix.c

@@ -1277,7 +1277,7 @@ static const grpc_event_engine_vtable vtable = {
 };
 
 const grpc_event_engine_vtable *grpc_init_poll_posix(void) {
-  if (!grpc_has_wakeup_fd) {
+  if (!grpc_has_wakeup_fd()) {
     return NULL;
   }
   if (!GRPC_LOG_IF_ERROR("pollset_global_init", pollset_global_init())) {

src/core/lib/iomgr/wakeup_fd_posix.c

@@ -41,9 +41,11 @@
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 
 static const grpc_wakeup_fd_vtable *wakeup_fd_vtable = NULL;
+
 int grpc_allow_specialized_wakeup_fd = 1;
 int grpc_allow_pipe_wakeup_fd = 1;
-int grpc_has_wakeup_fd = 1;
+int grpc_has_real_wakeup_fd = 1;
+int grpc_cv_wakeup_fds_enabled = 0;
 
 void grpc_wakeup_fd_global_init(void) {
   if (grpc_allow_specialized_wakeup_fd &&
@@ -53,27 +55,47 @@ void grpc_wakeup_fd_global_init(void) {
              grpc_pipe_wakeup_fd_vtable.check_availability()) {
     wakeup_fd_vtable = &grpc_pipe_wakeup_fd_vtable;
   } else {
-    grpc_has_wakeup_fd = 0;
-    wakeup_fd_vtable = &grpc_cv_wakeup_fd_vtable;
+    grpc_has_real_wakeup_fd = 0;
   }
 }
 
 void grpc_wakeup_fd_global_destroy(void) { wakeup_fd_vtable = NULL; }
 
+int grpc_has_wakeup_fd(void) {
+  return grpc_has_real_wakeup_fd || grpc_cv_wakeup_fds_enabled;
+}
+
+void grpc_enable_cv_wakeup_fds(int enable) {
+  grpc_cv_wakeup_fds_enabled = enable;
+}
+
 grpc_error *grpc_wakeup_fd_init(grpc_wakeup_fd *fd_info) {
+  if (grpc_cv_wakeup_fds_enabled) {
+    return grpc_cv_wakeup_fd_vtable.init(fd_info);
+  }
   return wakeup_fd_vtable->init(fd_info);
 }
 
 grpc_error *grpc_wakeup_fd_consume_wakeup(grpc_wakeup_fd *fd_info) {
+  if (grpc_cv_wakeup_fds_enabled) {
+    return grpc_cv_wakeup_fd_vtable.consume(fd_info);
+  }
   return wakeup_fd_vtable->consume(fd_info);
 }
 
 grpc_error *grpc_wakeup_fd_wakeup(grpc_wakeup_fd *fd_info) {
+  if (grpc_cv_wakeup_fds_enabled) {
+    return grpc_cv_wakeup_fd_vtable.wakeup(fd_info);
+  }
   return wakeup_fd_vtable->wakeup(fd_info);
 }
 
 void grpc_wakeup_fd_destroy(grpc_wakeup_fd *fd_info) {
-  wakeup_fd_vtable->destroy(fd_info);
+  if (grpc_cv_wakeup_fds_enabled) {
+    grpc_cv_wakeup_fd_vtable.destroy(fd_info);
+  } else {
+    wakeup_fd_vtable->destroy(fd_info);
+  }
 }
 
 #endif /* GPR_POSIX_WAKEUP_FD */

src/core/lib/iomgr/wakeup_fd_posix.h

@@ -71,6 +71,9 @@ void grpc_wakeup_fd_global_destroy(void);
  * purposes only.*/
 void grpc_wakeup_fd_global_init_force_fallback(void);
 
+int grpc_has_wakeup_fd(void);
+void grpc_enable_cv_wakeup_fds(int enable);
+
 typedef struct grpc_wakeup_fd grpc_wakeup_fd;
 
 typedef struct grpc_wakeup_fd_vtable {
@@ -89,7 +92,7 @@ struct grpc_wakeup_fd {
 
 extern int grpc_allow_specialized_wakeup_fd;
 extern int grpc_allow_pipe_wakeup_fd;
-extern int grpc_has_wakeup_fd;
+extern int grpc_has_real_wakeup_fd;
 
 #define GRPC_WAKEUP_FD_GET_READ_FD(fd_info) ((fd_info)->read_fd)