[Qemu-devel] [PATCH] glib: add compatibility interface for g_get_monotonic_time()

[Stefan Hajnoczi <stefanha@redhat.com>]

This patch fixes compilation errors when building against glib <2.28.0
due to the missing g_get_monotonic_time() function.

The compilation error in tests/libqos/virtio.c was introduced in commit
70556264a89a268efba1d7e8e341adcdd7881eb4 ("libqos: use microseconds
instead of iterations for virtio timeout").

Add a simple g_get_monotonic_time() implementation to compat-glib.h
based on code from vhost-user-test.c.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/glib-compat.h   | 14 ++++++++++++++
 tests/vhost-user-test.c | 18 +-----------------
 2 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/include/glib-compat.h b/include/glib-compat.h
index 4ae0671..9343742 100644
--- a/include/glib-compat.h
+++ b/include/glib-compat.h
@@ -26,6 +26,20 @@ static inline guint g_timeout_add_seconds(guint interval, GSourceFunc function,
 }
 #endif
 
+#if !GLIB_CHECK_VERSION(2, 28, 0)
+static inline gint64 g_get_monotonic_time(void)
+{
+    /* g_get_monotonic_time() is best-effort so we can use the wall clock as a
+     * fallback.
+     */
+
+    GTimeVal time;
+    g_get_current_time(&time);
+
+    return time.tv_sec * G_TIME_SPAN_SECOND + time.tv_usec;
+}
+#endif
+
 #ifdef _WIN32
 /*
  * g_poll has a problem on Windows when using
diff --git a/tests/vhost-user-test.c b/tests/vhost-user-test.c
index 75fedf0..af4012e 100644
--- a/tests/vhost-user-test.c
+++ b/tests/vhost-user-test.c
@@ -26,10 +26,6 @@
 #define G_TIME_SPAN_SECOND              (G_GINT64_CONSTANT(1000000))
 #endif
 
-#if GLIB_CHECK_VERSION(2, 28, 0)
-#define HAVE_MONOTONIC_TIME
-#endif
-
 #if GLIB_CHECK_VERSION(2, 32, 0)
 #define HAVE_MUTEX_INIT
 #define HAVE_COND_INIT
@@ -116,18 +112,6 @@ static VhostUserMemory memory;
 static GMutex *data_mutex;
 static GCond *data_cond;
 
-static gint64 _get_time(void)
-{
-#ifdef HAVE_MONOTONIC_TIME
-    return g_get_monotonic_time();
-#else
-    GTimeVal time;
-    g_get_current_time(&time);
-
-    return time.tv_sec * G_TIME_SPAN_SECOND + time.tv_usec;
-#endif
-}
-
 static GMutex *_mutex_new(void)
 {
     GMutex *mutex;
@@ -210,7 +194,7 @@ static void read_guest_mem(void)
 
     g_mutex_lock(data_mutex);
 
-    end_time = _get_time() + 5 * G_TIME_SPAN_SECOND;
+    end_time = g_get_monotonic_time() + 5 * G_TIME_SPAN_SECOND;
     while (!fds_num) {
         if (!_cond_wait_until(data_cond, data_mutex, end_time)) {
             /* timeout has passed */
-- 
1.9.3