netpoll: make __netpoll_cleanup non-block

Like the previous patch, slave_disable_netpoll() and __netpoll_cleanup()
may be called with read_lock() held too, so we should make them
non-block, by moving the cleanup and kfree() to call_rcu_bh() callbacks.

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index bf2d51eec0f3..907812efb4d9 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -23,6 +23,7 @@ struct netpoll {
         u8 remote_mac[ETH_ALEN];
 
         struct list_head rx; /* rx_np list element */
+        struct rcu_head rcu;
 };
 
 struct netpoll_info {
@@ -38,6 +39,7 @@ struct netpoll_info {
         struct delayed_work tx_work;
 
         struct netpoll *netpoll;
+        struct rcu_head rcu;
 };
 
 void netpoll_send_udp(struct netpoll *np, const char *msg, int len);
@@ -48,6 +50,7 @@ int netpoll_setup(struct netpoll *np);
 int netpoll_trap(void);
 void netpoll_set_trap(int trap);
 void __netpoll_cleanup(struct netpoll *np);
+void __netpoll_free_rcu(struct netpoll *np);
 void netpoll_cleanup(struct netpoll *np);
 int __netpoll_rx(struct sk_buff *skb);
 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,