DM: add init/deinit function for mevent

Current, mevent cleanup path has issue. There are possible
following calling sequence happen when reboot/poweroff UOS:
 1. mevent_dispatch() calls mevent_destroy
 2. do_close_post calls some virtual device deinit to delete
    mevent.

This patch introduce mevent init/deinit to make sure:
 1. mevent init
 2. mevent_add is called when init virtual device
 3. mevent_del is called when deinit virtual device
 4. mevent deinit

Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Reviewed-by: Zhao Yakui <yakui.zhao@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>

Author: fyin1

devicemodel/core/main.c

@@ -770,6 +770,13 @@ main(int argc, char *argv[])
 			goto fail;
 		}
 
+		err = mevent_init();
+		if (err) {
+			fprintf(stderr, "Unable to initialize mevent (%d)\n",
+				errno);
+			goto mevent_fail;
+		}
+
 		init_mem();
 		init_inout();
 		pci_irq_init(ctx);
@@ -848,6 +855,7 @@ main(int argc, char *argv[])
 		vrtc_deinit(ctx);
 		atkbdc_deinit(ctx);
 		vm_unsetup_memory(ctx);
+		mevent_deinit();
 		vm_destroy(ctx);
 		vm_close(ctx);
 		_ctx = 0;
@@ -861,6 +869,7 @@ main(int argc, char *argv[])
 	monitor_close();
 	vrtc_deinit(ctx);
 	atkbdc_deinit(ctx);
+mevent_fail:
 	vm_unsetup_memory(ctx);
 fail:
 	vm_destroy(ctx);

devicemodel/core/mevent.c

@@ -58,6 +58,7 @@
 #define	MEV_DISABLE	3
 #define	MEV_DEL_PENDING	4
 
+static int epoll_fd;
 static pthread_t mevent_tid;
 static int mevent_pipefd[2];
 static pthread_mutex_t mevent_lmutex = PTHREAD_MUTEX_INITIALIZER;
@@ -341,23 +342,38 @@ mevent_set_name(void)
 	pthread_setname_np(mevent_tid, "mevent");
 }
 
+int
+mevent_init(void)
+{
+	epoll_fd = epoll_create1(0);
+	assert(epoll_fd >= 0);
+
+	if (epoll_fd >= 0)
+		return 0;
+	else
+		return -1;
+}
+
+void
+mevent_deinit(void)
+{
+	mevent_destroy();
+	close(epoll_fd);
+}
+
 void
 mevent_dispatch(void)
 {
 	struct ctl_event clist[MEVENT_MAX];
 	struct epoll_event eventlist[MEVENT_MAX];
 
 	struct mevent *pipev;
-	int mfd;
 	int numev;
 	int ret;
 
 	mevent_tid = pthread_self();
 	mevent_set_name();
 
-	mfd = epoll_create1(0);
-	assert(mfd > 0);
-
 	/*
 	 * Open the pipe that will be used for other threads to force
 	 * the blocking kqueue call to exit by writing to it. Set the
@@ -385,19 +401,19 @@ mevent_dispatch(void)
 		int i;
 		struct epoll_event *e;
 
-		numev = mevent_build(mfd, clist);
+		numev = mevent_build(epoll_fd, clist);
 
 		for (i = 0; i < numev; i++) {
 			e = &clist[i].ee;
-			ret = epoll_ctl(mfd, clist[i].op, clist[i].fd, e);
+			ret = epoll_ctl(epoll_fd, clist[i].op, clist[i].fd, e);
 			if (ret == -1)
 				perror("Error return from epoll_ctl");
 		}
 
 		/*
 		 * Block awaiting events
 		 */
-		ret = epoll_wait(mfd, eventlist, MEVENT_MAX, -1);
+		ret = epoll_wait(epoll_fd, eventlist, MEVENT_MAX, -1);
 		if (ret == -1 && errno != EINTR)
 			perror("Error return from epoll_wait");
 
@@ -409,7 +425,5 @@ mevent_dispatch(void)
 		if (vm_get_suspend_mode() != VM_SUSPEND_NONE)
 			break;
 	}
-	mevent_build(mfd, clist);
-	mevent_destroy();
-	close(mfd);
+	mevent_build(epoll_fd, clist);
 }

devicemodel/include/mevent.h

@@ -49,6 +49,8 @@ int	mevent_delete_close(struct mevent *evp);
 int	mevent_notify(void);
 
 void	mevent_dispatch(void);
+int	mevent_init(void);
+void	mevent_deinit(void);
 
 #define list_foreach_safe(var, head, field, tvar)	\
 for ((var) = LIST_FIRST((head));			\