diff options
| author | kmacy <kmacy@FreeBSD.org> | 2009-05-07 19:57:14 +0000 |
|---|---|---|
| committer | kmacy <kmacy@FreeBSD.org> | 2009-05-07 19:57:14 +0000 |
| commit | 35d0919f73b2c1f73aa5af18b5242d425502e00e (patch) | |
| tree | 97e9474ea02fb7f8241b919151c81e55a6091fe2 /sys/sys/buf_ring.h | |
| parent | fa0fd85038112daf1c7af75811d6cc4764c7788f (diff) | |
| download | FreeBSD-src-35d0919f73b2c1f73aa5af18b5242d425502e00e.zip FreeBSD-src-35d0919f73b2c1f73aa5af18b5242d425502e00e.tar.gz | |
No man page currently exists so comment the two uncommented
non-trivial functions
Diffstat (limited to 'sys/sys/buf_ring.h')
| -rw-r--r-- | sys/sys/buf_ring.h | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/sys/sys/buf_ring.h b/sys/sys/buf_ring.h index efea85a..0ffe5a2 100644 --- a/sys/sys/buf_ring.h +++ b/sys/sys/buf_ring.h @@ -1,6 +1,6 @@ /************************************************************************** * - * Copyright (c) 2007,2008 Kip Macy kmacy@freebsd.org + * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -69,7 +69,10 @@ struct buf_ring { void *br_ring[0]; }; - +/* + * multi-producer safe lock-free ring buffer enqueue + * + */ static __inline int buf_ring_enqueue(struct buf_ring *br, void *buf) { @@ -169,8 +172,9 @@ buf_ring_dequeue_mc(struct buf_ring *br) } /* - * Single-Consumer dequeue for uses where dequeue - * is protected by a lock + * single-consumer dequeue + * use where dequeue is protected by a lock + * e.g. a network driver's tx queue lock */ static __inline void * buf_ring_dequeue_sc(struct buf_ring *br) @@ -208,6 +212,11 @@ buf_ring_dequeue_sc(struct buf_ring *br) return (buf); } +/* + * return a pointer to the first entry in the ring + * without modifying it, or NULL if the ring is empty + * race-prone if not protected by a lock + */ static __inline void * buf_ring_peek(struct buf_ring *br) { |
