Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/kernel/include/linux/circ_buf.h b/kernel/include/linux/circ_buf.h
new file mode 100644
index 000000000..90f2471dc
--- /dev/null
+++ b/kernel/include/linux/circ_buf.h
@@ -0,0 +1,36 @@
+/*
+ * See Documentation/circular-buffers.txt for more information.
+ */
+
+#ifndef _LINUX_CIRC_BUF_H
+#define _LINUX_CIRC_BUF_H 1
+
+struct circ_buf {
+	char *buf;
+	int head;
+	int tail;
+};
+
+/* Return count in buffer.  */
+#define CIRC_CNT(head,tail,size) (((head) - (tail)) & ((size)-1))
+
+/* Return space available, 0..size-1.  We always leave one free char
+   as a completely full buffer has head == tail, which is the same as
+   empty.  */
+#define CIRC_SPACE(head,tail,size) CIRC_CNT((tail),((head)+1),(size))
+
+/* Return count up to the end of the buffer.  Carefully avoid
+   accessing head and tail more than once, so they can change
+   underneath us without returning inconsistent results.  */
+#define CIRC_CNT_TO_END(head,tail,size) \
+	({int end = (size) - (tail); \
+	  int n = ((head) + end) & ((size)-1); \
+	  n < end ? n : end;})
+
+/* Return space available up to the end of the buffer.  */
+#define CIRC_SPACE_TO_END(head,tail,size) \
+	({int end = (size) - 1 - (head); \
+	  int n = (end + (tail)) & ((size)-1); \
+	  n <= end ? n : end+1;})
+
+#endif /* _LINUX_CIRC_BUF_H  */