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authorJon Maloy <jon.maloy@ericsson.com>2019-08-15 16:42:50 +0200
committerDavid S. Miller <davem@davemloft.net>2019-08-18 14:01:07 -0700
commite654f9f53b45fde3fcc8051830b212c7a8f36148 (patch)
tree1b3b3af06442bae94101ca20f1c0b6ca06d54e44 /net/tipc/node.c
parent10086b345385bc1ca67b260aff236e742e2e630e (diff)
downloadlinux-e654f9f53b45fde3fcc8051830b212c7a8f36148.tar.bz2
tipc: clean up skb list lock handling on send path
The policy for handling the skb list locks on the send and receive paths is simple. - On the send path we never need to grab the lock on the 'xmitq' list when the destination is an exernal node. - On the receive path we always need to grab the lock on the 'inputq' list, irrespective of source node. However, when transmitting node local messages those will eventually end up on the receive path of a local socket, meaning that the argument 'xmitq' in tipc_node_xmit() will become the 'ínputq' argument in the function tipc_sk_rcv(). This has been handled by always initializing the spinlock of the 'xmitq' list at message creation, just in case it may end up on the receive path later, and despite knowing that the lock in most cases never will be used. This approach is inaccurate and confusing, and has also concealed the fact that the stated 'no lock grabbing' policy for the send path is violated in some cases. We now clean up this by never initializing the lock at message creation, instead doing this at the moment we find that the message actually will enter the receive path. At the same time we fix the four locations where we incorrectly access the spinlock on the send/error path. This patch also reverts commit d12cffe9329f ("tipc: ensure head->lock is initialised") which has now become redundant. CC: Eric Dumazet <edumazet@google.com> Reported-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/node.c')
-rw-r--r--net/tipc/node.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/net/tipc/node.c b/net/tipc/node.c
index 1bdcf0fc1a4d..c8f6177dd5a2 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -1444,13 +1444,14 @@ int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
if (in_own_node(net, dnode)) {
tipc_loopback_trace(net, list);
+ spin_lock_init(&list->lock);
tipc_sk_rcv(net, list);
return 0;
}
n = tipc_node_find(net, dnode);
if (unlikely(!n)) {
- skb_queue_purge(list);
+ __skb_queue_purge(list);
return -EHOSTUNREACH;
}
@@ -1459,7 +1460,7 @@ int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
if (unlikely(bearer_id == INVALID_BEARER_ID)) {
tipc_node_read_unlock(n);
tipc_node_put(n);
- skb_queue_purge(list);
+ __skb_queue_purge(list);
return -EHOSTUNREACH;
}
@@ -1491,7 +1492,7 @@ int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
{
struct sk_buff_head head;
- skb_queue_head_init(&head);
+ __skb_queue_head_init(&head);
__skb_queue_tail(&head, skb);
tipc_node_xmit(net, &head, dnode, selector);
return 0;