svn commit: r309236 - head/sys/dev/hyperv/vmbus

[Sepherosa Ziehau]

Author: sephe
Date: Mon Nov 28 06:53:00 2016
New Revision: 309236
URL: https://svnweb.freebsd.org/changeset/base/309236

Log:
  hyperv/vmbus: Make sure that the allocated GPADL is not zero.
  
  MFC after:	1 week
  Sponsored by:	Microsoft
  Differential Revision:	https://reviews.freebsd.org/D8631

Modified:
  head/sys/dev/hyperv/vmbus/vmbus.c

Modified: head/sys/dev/hyperv/vmbus/vmbus.c
==============================================================================
--- head/sys/dev/hyperv/vmbus/vmbus.c	Mon Nov 28 06:40:26 2016	(r309235)
+++ head/sys/dev/hyperv/vmbus/vmbus.c	Mon Nov 28 06:53:00 2016	(r309236)
@@ -325,7 +325,13 @@ vmbus_msghc_wakeup(struct vmbus_softc *s
 uint32_t
 vmbus_gpadl_alloc(struct vmbus_softc *sc)
 {
-	return atomic_fetchadd_int(&sc->vmbus_gpadl, 1);
+	uint32_t gpadl;
+
+again:
+	gpadl = atomic_fetchadd_int(&sc->vmbus_gpadl, 1); 
+	if (gpadl == 0)
+		goto again;
+	return (gpadl);
 }
 
 static int