Merge pull request #10440 from danzh2010/udpserver

Modify  udp_server to postpone shutdown_fd() during shutdown.

src/core/lib/iomgr/udp_server.c

@@ -79,10 +79,15 @@ struct grpc_udp_listener {
   grpc_resolved_address addr;
   grpc_closure read_closure;
   grpc_closure write_closure;
+  // To be called when corresponding QuicGrpcServer closes all active
+  // connections.
+  grpc_closure orphan_fd_closure;
   grpc_closure destroyed_closure;
   grpc_udp_server_read_cb read_cb;
   grpc_udp_server_write_cb write_cb;
   grpc_udp_server_orphan_cb orphan_cb;
+  // True if orphan_cb is trigered.
+  bool orphan_notified;
 
   struct grpc_udp_listener *next;
 };
@@ -146,6 +151,14 @@ grpc_udp_server *grpc_udp_server_create(const grpc_channel_args *args) {
   return s;
 }
 
+static void shutdown_fd(grpc_exec_ctx *exec_ctx, void *fd, grpc_error *error) {
+  grpc_fd_shutdown(exec_ctx, (grpc_fd *)fd, GRPC_ERROR_REF(error));
+}
+
+static void dummy_cb(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
+  // No-op.
+}
+
 static void finish_shutdown(grpc_exec_ctx *exec_ctx, grpc_udp_server *s) {
   if (s->shutdown_complete != NULL) {
     grpc_closure_sched(exec_ctx, s->shutdown_complete, GRPC_ERROR_NONE);
@@ -195,12 +208,16 @@ static void deactivated_all_ports(grpc_exec_ctx *exec_ctx, grpc_udp_server *s) {
 
       grpc_closure_init(&sp->destroyed_closure, destroyed_port, s,
                         grpc_schedule_on_exec_ctx);
-
+      if (!sp->orphan_notified) {
         /* Call the orphan_cb to signal that the FD is about to be closed and
-       * should no longer be used. */
+         * should no longer be used. Because at this point, all listening ports
+         * have been shutdown already, no need to shutdown again.*/
+        grpc_closure_init(&sp->orphan_fd_closure, dummy_cb, sp->emfd,
+                          grpc_schedule_on_exec_ctx);
         GPR_ASSERT(sp->orphan_cb);
-      sp->orphan_cb(exec_ctx, sp->emfd, sp->server->user_data);
-
+        sp->orphan_cb(exec_ctx, sp->emfd, &sp->orphan_fd_closure,
+                      sp->server->user_data);
+      }
       grpc_fd_orphan(exec_ctx, sp->emfd, &sp->destroyed_closure, NULL,
                      "udp_listener_shutdown");
     }
@@ -225,9 +242,11 @@ void grpc_udp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_udp_server *s,
   if (s->active_ports) {
     for (sp = s->head; sp; sp = sp->next) {
       GPR_ASSERT(sp->orphan_cb);
-      sp->orphan_cb(exec_ctx, sp->emfd, sp->server->user_data);
-      grpc_fd_shutdown(exec_ctx, sp->emfd, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
-                                               "Server destroyed"));
+      grpc_closure_init(&sp->orphan_fd_closure, shutdown_fd, sp->emfd,
+                        grpc_schedule_on_exec_ctx);
+      sp->orphan_cb(exec_ctx, sp->emfd, &sp->orphan_fd_closure,
+                    sp->server->user_data);
+      sp->orphan_notified = true;
     }
     gpr_mu_unlock(&s->mu);
   } else {
@@ -391,6 +410,7 @@ static int add_socket_to_server(grpc_udp_server *s, int fd,
     sp->read_cb = read_cb;
     sp->write_cb = write_cb;
     sp->orphan_cb = orphan_cb;
+    sp->orphan_notified = false;
     GPR_ASSERT(sp->emfd);
     gpr_mu_unlock(&s->mu);
     gpr_free(name);

src/core/lib/iomgr/udp_server.h

@@ -55,7 +55,9 @@ typedef void (*grpc_udp_server_write_cb)(grpc_exec_ctx *exec_ctx, grpc_fd *emfd,
 
 /* Called when the grpc_fd is about to be orphaned (and the FD closed). */
 typedef void (*grpc_udp_server_orphan_cb)(grpc_exec_ctx *exec_ctx,
-                                          grpc_fd *emfd, void *user_data);
+                                          grpc_fd *emfd,
+                                          grpc_closure *shutdown_fd_callback,
+                                          void *user_data);
 
 /* Create a server, initially not bound to any ports */
 grpc_udp_server *grpc_udp_server_create(const grpc_channel_args *args);

test/core/iomgr/udp_server_test.c

@@ -91,7 +91,7 @@ static void on_write(grpc_exec_ctx *exec_ctx, grpc_fd *emfd, void *user_data) {
 }
 
 static void on_fd_orphaned(grpc_exec_ctx *exec_ctx, grpc_fd *emfd,
-                           void *user_data) {
+                           grpc_closure *closure, void *user_data) {
   gpr_log(GPR_INFO, "gRPC FD about to be orphaned: %d",
           grpc_fd_wrapped_fd(emfd));
   g_number_of_orphan_calls++;
@@ -228,9 +228,9 @@ static void test_no_op_with_port_and_start(void) {
   grpc_udp_server_destroy(&exec_ctx, s, NULL);
   grpc_exec_ctx_finish(&exec_ctx);
 
-  /* The server had a single FD, which is orphaned once in *
-   * deactivated_all_ports, and once in grpc_udp_server_destroy. */
-  GPR_ASSERT(g_number_of_orphan_calls == 2);
+  /* The server had a single FD, which is orphaned exactly once in *
+   * grpc_udp_server_destroy. */
+  GPR_ASSERT(g_number_of_orphan_calls == 1);
 }
 
 static void test_receive(int number_of_clients) {
@@ -297,9 +297,9 @@ static void test_receive(int number_of_clients) {
   grpc_udp_server_destroy(&exec_ctx, s, NULL);
   grpc_exec_ctx_finish(&exec_ctx);
 
-  /* The server had a single FD, which is orphaned once in *
-   * deactivated_all_ports, and once in grpc_udp_server_destroy. */
-  GPR_ASSERT(g_number_of_orphan_calls == 2);
+  /* The server had a single FD, which is orphaned exactly once in *
+   * grpc_udp_server_destroy. */
+  GPR_ASSERT(g_number_of_orphan_calls == 1);
 
   /* The write callback should have fired a few times. */
   GPR_ASSERT(g_number_of_writes > 0);