From 8a275a6a30ba871eb34ea41c1fbb507039f4c0dc Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Wed, 26 Oct 2011 15:33:44 -0400 Subject: [PATCH] tipc: Fix node lock reclamation issues in broadcast link reception Fixes a pair of problems in broadcast link message reception code relating to the reclamation of the node lock after consuming an in-sequence message. 1) Now retests to see if the sending node is still up after reclaiming the node lock, and bails out if it is non-operational. 2) Now manipulates the node's deferred message queue only after reclaiming the node lock, rather than using queue head pointer information that was cached previously. Signed-off-by: Allan Stephens Signed-off-by: Paul Gortmaker --- net/tipc/bcast.c | 58 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 40 insertions(+), 18 deletions(-) diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c index 7342abc2cfa1..e7df313020ce 100644 --- a/net/tipc/bcast.c +++ b/net/tipc/bcast.c @@ -474,7 +474,7 @@ void tipc_bclink_recv_pkt(struct sk_buff *buf) struct tipc_node *node; u32 next_in; u32 seqno; - struct sk_buff *deferred; + int deferred; /* Screen out unwanted broadcast messages */ @@ -489,6 +489,8 @@ void tipc_bclink_recv_pkt(struct sk_buff *buf) if (unlikely(!node->bclink.supported)) goto unlock; + /* Handle broadcast protocol message */ + if (unlikely(msg_user(msg) == BCAST_PROTOCOL)) { if (msg_type(msg) != STATE_MSG) goto unlock; @@ -513,11 +515,11 @@ void tipc_bclink_recv_pkt(struct sk_buff *buf) /* Handle in-sequence broadcast message */ -receive: - next_in = mod(node->bclink.last_in + 1); seqno = msg_seqno(msg); + next_in = mod(node->bclink.last_in + 1); if (likely(seqno == next_in)) { +receive: bcl->stats.recv_info++; node->bclink.last_in++; bclink_set_gap(node); @@ -551,23 +553,40 @@ receive: buf_discard(buf); } buf = NULL; + + /* Determine new synchronization state */ + tipc_node_lock(node); - deferred = node->bclink.deferred_head; - if (deferred && (buf_seqno(deferred) == mod(next_in + 1))) { - buf = deferred; - msg = buf_msg(buf); - node->bclink.deferred_head = deferred->next; - goto receive; - } - } else if (less(next_in, seqno)) { + if (unlikely(!tipc_node_is_up(node))) + goto unlock; + + if (!node->bclink.deferred_head) + goto unlock; + + msg = buf_msg(node->bclink.deferred_head); + seqno = msg_seqno(msg); + next_in = mod(next_in + 1); + if (seqno != next_in) + goto unlock; + + /* Take in-sequence message from deferred queue & deliver it */ + + buf = node->bclink.deferred_head; + node->bclink.deferred_head = buf->next; + goto receive; + } + + /* Handle out-of-sequence broadcast message */ + + if (less(next_in, seqno)) { u32 gap_after = node->bclink.gap_after; u32 gap_to = node->bclink.gap_to; - if (tipc_link_defer_pkt(&node->bclink.deferred_head, - &node->bclink.deferred_tail, - buf)) { + deferred = tipc_link_defer_pkt(&node->bclink.deferred_head, + &node->bclink.deferred_tail, + buf); + if (deferred) { node->bclink.nack_sync++; - bcl->stats.deferred_recv++; if (seqno == mod(gap_after + 1)) node->bclink.gap_after = seqno; else if (less(gap_after, seqno) && less(seqno, gap_to)) @@ -579,9 +598,12 @@ receive: bclink_send_nack(node); bclink_set_gap(node); } - } else { - bcl->stats.duplicates++; - } + } else + deferred = 0; + + if (deferred) + bcl->stats.deferred_recv++; + unlock: tipc_node_unlock(node); exit: -- 2.34.1