From 7d967b673c2ff992205be051ffebc39e1a323400 Mon Sep 17 00:00:00 2001 From: Jon Paul Maloy Date: Sun, 28 Jun 2015 09:44:44 -0400 Subject: [PATCH] tipc: purge backlog queue counters when broadcast link is reset In commit 1f66d161ab3d8b518903fa6c3f9c1f48d6919e74 ("tipc: introduce starvation free send algorithm") we introduced a counter per priority level for buffers in the link backlog queue. We also introduced a new function tipc_link_purge_backlog(), to reset these counters to zero when the link is reset. Unfortunately, we missed to call this function when the broadcast link is reset, with the result that the values of these counters might be permanently skewed when new nodes are attached. This may in the worst case lead to permananent, but spurious, broadcast link congestion, where no broadcast packets can be sent at all. We fix this bug with this commit. Signed-off-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/bcast.c | 5 +++++ net/tipc/link.c | 2 +- net/tipc/link.h | 1 + 3 files changed, 7 insertions(+), 1 deletion(-) diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c index 4906ca3c0f3a..a816382fc8af 100644 --- a/net/tipc/bcast.c +++ b/net/tipc/bcast.c @@ -108,6 +108,11 @@ void tipc_bclink_remove_node(struct net *net, u32 addr) tipc_bclink_lock(net); tipc_nmap_remove(&tn->bclink->bcast_nodes, addr); + + /* Last node? => reset backlog queue */ + if (!tn->bclink->bcast_nodes.count) + tipc_link_purge_backlog(&tn->bclink->link); + tipc_bclink_unlock(net); } diff --git a/net/tipc/link.c b/net/tipc/link.c index ca8b8e0f49b5..eaa9fe54b4ae 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -404,7 +404,7 @@ void tipc_link_reset_fragments(struct tipc_link *l_ptr) l_ptr->reasm_buf = NULL; } -static void tipc_link_purge_backlog(struct tipc_link *l) +void tipc_link_purge_backlog(struct tipc_link *l) { __skb_queue_purge(&l->backlogq); l->backlog[TIPC_LOW_IMPORTANCE].len = 0; diff --git a/net/tipc/link.h b/net/tipc/link.h index 0c02c973e985..ae0a0ea572f2 100644 --- a/net/tipc/link.h +++ b/net/tipc/link.h @@ -218,6 +218,7 @@ void tipc_link_reset_fragments(struct tipc_link *l_ptr); int tipc_link_is_up(struct tipc_link *l_ptr); int tipc_link_is_active(struct tipc_link *l_ptr); void tipc_link_purge_queues(struct tipc_link *l_ptr); +void tipc_link_purge_backlog(struct tipc_link *l); void tipc_link_reset_all(struct tipc_node *node); void tipc_link_reset(struct tipc_link *l_ptr); int tipc_link_xmit_skb(struct net *net, struct sk_buff *skb, u32 dest,