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2 .\" Written by: Kip Macy <kmacy@@FreeBSD.org>
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28 .Dd September 27, 2012
36 .Nm drbr_dequeue_cond ,
40 .Nd network driver interface to buf_ring
46 .Fn drbr_free "struct buf_ring *br" "struct malloc_type *type"
48 .Fn drbr_enqueue "struct ifnet *ifp" "struct buf_ring *br" "struct mbuf *m"
50 .Fn drbr_dequeue "struct ifnet *ifp" "struct buf_ring *br"
52 .Fn drbr_dequeue_cond "struct ifnet *ifp" "struct buf_ring *br" "int (*func) (struct mbuf *, void *)" "void *arg"
54 .Fn drbr_flush "struct ifnet *ifp" "struct buf_ring *br"
56 .Fn drbr_empty "struct ifnet *ifp" "struct buf_ring *br"
58 .Fn drbr_inuse "struct ifnet *ifp" "struct buf_ring *br"
62 functions provide an API to network drivers for using
64 for enqueueing and dequeueing packets.
65 This is meant as a replacement for the IFQ interface for packet queuing.
66 It allows a packet to be enqueued with a single atomic and packet
67 dequeue to be done without any per-packet atomics as it is protected
68 by the driver's tx queue lock.
73 will assert that the tx queue lock is held when it is called.
77 function frees all the enqueued mbufs and then frees the buf_ring.
81 function is used to enqueue an mbuf to a buf_ring, falling back to the
88 function is used to dequeue an mbuf from a buf_ring or, if
90 is enabled, from the ifnet's IFQ.
94 function is used to conditionally dequeue an mbuf from a buf_ring based
104 function frees all mbufs enqueued in the buf_ring and the ifnet's IFQ.
110 if there are no mbufs enqueued,
116 function returns the number of mbufs enqueued.
117 Note to users that this is intrinsically racy as there is no guarantee that
118 there will not be more mbufs when
121 Provided the tx queue lock is held there will not be less.
127 if there are no slots available in the buf_ring and
134 .Fn drbr_dequeue_cond
135 functions return an mbuf on success and
137 if the buf_ring is empty.
139 These functions were introduced in