From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: 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 Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior 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 --- kernel/include/linux/circ_buf.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 kernel/include/linux/circ_buf.h (limited to 'kernel/include/linux/circ_buf.h') 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 */ -- cgit 1.2.3-korg