[PATCH] qemu-timer: allow freeing a NULL timer

[Paolo Bonzini <pbonzini@redhat.com>]

Since 5f8e93c3e2 ("util/qemu-timer: Make timer_free() imply timer_del()", 2021-01-08)
it is not possible anymore to pass a NULL pointer to timer_free().  Previously
it would do nothing as it would simply pass NULL down to g_free().

Rectify this, which also fixes "-chardev braille" when there is no device.

Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 include/qemu/timer.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/qemu/timer.h b/include/qemu/timer.h
index 1678238384..88ef114689 100644
--- a/include/qemu/timer.h
+++ b/include/qemu/timer.h
@@ -629,8 +629,10 @@ void timer_del(QEMUTimer *ts);
  */
 static inline void timer_free(QEMUTimer *ts)
 {
-    timer_del(ts);
-    g_free(ts);
+    if (ts) {
+        timer_del(ts);
+        g_free(ts);
+    }
 }
 
 /**
-- 
2.26.2