From 619a60ee04be33238721a15c1f9704a2a515a33e Mon Sep 17 00:00:00 2001 From: Vlad Yasevich Date: Thu, 2 Jan 2014 14:39:44 -0500 Subject: [PATCH] sctp: Remove outqueue empty state The SCTP outqueue structure maintains a data chunks that are pending transmission, the list of chunks that are pending a retransmission and a length of data in flight. It also tries to keep the emtpy state so that it can performe shutdown sequence or notify user. The problem is that the empy state is inconsistently tracked. It is possible to completely drain the queue without sending anything when using PR-SCTP. In this case, the empty state will not be correctly state as report by Jamal Hadi Salim . This can cause an association to be perminantly stuck in the SHUTDOWN_PENDING state. Additionally, SCTP is incredibly inefficient when setting the empty state. Even though all the data is availaible in the outqueue structure, we ignore it and walk a list of trasnports. In the end, we can completely remove the extra empty state and figure out if the queue is empty by looking at 3 things: length of pending data, length of in-flight data, and exisiting of retransmit data. All of these are already in the strucutre. Reported-by: Jamal Hadi Salim Signed-off-by: Vlad Yasevich Acked-by: Neil Horman Tested-by: Jamal Hadi Salim Signed-off-by: David S. Miller --- include/net/sctp/structs.h | 3 --- net/sctp/outqueue.c | 32 +++++++------------------------- 2 files changed, 7 insertions(+), 28 deletions(-) diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index 67b5d0068273..0a248b323d87 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -1046,9 +1046,6 @@ struct sctp_outq { /* Corked? */ char cork; - - /* Is this structure empty? */ - char empty; }; void sctp_outq_init(struct sctp_association *, struct sctp_outq *); diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c index f51ba985a36e..59268f6e2c36 100644 --- a/net/sctp/outqueue.c +++ b/net/sctp/outqueue.c @@ -208,8 +208,6 @@ void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q) INIT_LIST_HEAD(&q->retransmit); INIT_LIST_HEAD(&q->sacked); INIT_LIST_HEAD(&q->abandoned); - - q->empty = 1; } /* Free the outqueue structure and any related pending chunks. @@ -332,7 +330,6 @@ int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS); else SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS); - q->empty = 0; break; } } else { @@ -654,7 +651,6 @@ redo: if (chunk->fast_retransmit == SCTP_NEED_FRTX) chunk->fast_retransmit = SCTP_DONT_FRTX; - q->empty = 0; q->asoc->stats.rtxchunks++; break; } @@ -1065,8 +1061,6 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) sctp_transport_reset_timers(transport); - q->empty = 0; - /* Only let one DATA chunk get bundled with a * COOKIE-ECHO chunk. */ @@ -1275,29 +1269,17 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) "advertised peer ack point:0x%x\n", __func__, asoc, ctsn, asoc->adv_peer_ack_point); - /* See if all chunks are acked. - * Make sure the empty queue handler will get run later. - */ - q->empty = (list_empty(&q->out_chunk_list) && - list_empty(&q->retransmit)); - if (!q->empty) - goto finish; - - list_for_each_entry(transport, transport_list, transports) { - q->empty = q->empty && list_empty(&transport->transmitted); - if (!q->empty) - goto finish; - } - - pr_debug("%s: sack queue is empty\n", __func__); -finish: - return q->empty; + return sctp_outq_is_empty(q); } -/* Is the outqueue empty? */ +/* Is the outqueue empty? + * The queue is empty when we have not pending data, no in-flight data + * and nothing pending retransmissions. + */ int sctp_outq_is_empty(const struct sctp_outq *q) { - return q->empty; + return q->out_qlen == 0 && q->outstanding_bytes == 0 && + list_empty(&q->retransmit); } /******************************************************************** -- 2.34.1