Provide a set of inline functions to manage simple mbuf(9) queues, based

on queue(3)'s STAILQ.  Utilize them in cxgb(4) and Xen, deleting home
grown implementations.

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.

1 files changed, 96 insertions, 0 deletions

diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index 11d8297..1932de4 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -1199,5 +1199,101 @@ rt_m_getfib(struct mbuf *m)
  #define M_PROFILE(m)
 #endif
 
+struct mbufq {
+	STAILQ_HEAD(, mbuf)	mq_head;
+	int			mq_len;
+	int			mq_maxlen;
+};
+
+static inline void
+mbufq_init(struct mbufq *mq, int maxlen)
+{
+
+	STAILQ_INIT(&mq->mq_head);
+	mq->mq_maxlen = maxlen;
+	mq->mq_len = 0;
+}
+
+static inline struct mbuf *
+mbufq_flush(struct mbufq *mq)
+{
+	struct mbuf *m;
+
+	m = STAILQ_FIRST(&mq->mq_head);
+	STAILQ_INIT(&mq->mq_head);
+	mq->mq_len = 0;
+	return (m);
+}
+
+static inline void
+mbufq_drain(struct mbufq *mq)
+{
+	struct mbuf *m, *n;
+
+	n = mbufq_flush(mq);
+	while ((m = n) != NULL) {
+		n = STAILQ_NEXT(m, m_stailqpkt);
+		m_freem(m);
+	}
+}
+
+static inline struct mbuf *
+mbufq_first(const struct mbufq *mq)
+{
+
+	return (STAILQ_FIRST(&mq->mq_head));
+}
+
+static inline struct mbuf *
+mbufq_last(const struct mbufq *mq)
+{
+
+	return (STAILQ_LAST(&mq->mq_head, mbuf, m_stailqpkt));
+}
 
+static inline int
+mbufq_full(const struct mbufq *mq)
+{
+
+	return (mq->mq_len >= mq->mq_maxlen);
+}
+
+static inline int
+mbufq_len(const struct mbufq *mq)
+{
+
+	return (mq->mq_len);
+}
+
+static inline int
+mbufq_enqueue(struct mbufq *mq, struct mbuf *m)
+{
+
+	if (mbufq_full(mq))
+		return (ENOBUFS);
+	STAILQ_INSERT_TAIL(&mq->mq_head, m, m_stailqpkt);
+	mq->mq_len++;
+	return (0);
+}
+
+static inline struct mbuf *
+mbufq_dequeue(struct mbufq *mq)
+{
+	struct mbuf *m;
+
+	m = STAILQ_FIRST(&mq->mq_head);
+	if (m) {
+		STAILQ_REMOVE_HEAD(&mq->mq_head, m_stailqpkt);
+		mq->mq_len--;
+	}
+	return (m);
+}
+
+static inline void
+mbufq_prepend(struct mbufq *mq, struct mbuf *m)
+{
+
+	STAILQ_INSERT_HEAD(&mq->mq_head, m, m_stailqpkt);
+	mq->mq_len++;
+}
 #endif /* !_SYS_MBUF_H_ */