Define Linux-style <preempt.h> interface.

Use it to disable sleeping in spinlock and rcu-read regions.

Signed-off-by: Keir Fraser <keir@xen.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/xen/common/preempt.c b/xen/common/preempt.c
new file mode 100644
index 0000000000..e2133ea50a
--- /dev/null
+++ b/xen/common/preempt.c
@@ -0,0 +1,25 @@
+/******************************************************************************
+ * preempt.c
+ * 
+ * Track atomic regions in the hypervisor which disallow sleeping.
+ * 
+ * Copyright (c) 2010, Keir Fraser <keir@xen.org>
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <xen/preempt.h>
+
+DEFINE_PER_CPU(unsigned int, __preempt_count);