From fbeec2e1552949002065435c9829dc244ad85407 Mon Sep 17 00:00:00 2001 From: Jeff Moyer Date: Wed, 22 Jun 2005 22:05:59 -0700 Subject: [NETPOLL]: allow multiple netpoll_clients to register against one interface This patch provides support for registering multiple netpoll clients to the same network device. Only one of these clients may register an rx_hook, however. In practice, this restriction has not been problematic. It is worth mentioning, though, that the current design can be easily extended to allow for the registration of multiple rx_hooks. The basic idea of the patch is that the rx_np pointer in the netpoll_info structure points to the struct netpoll that has rx_hook filled in. Aside from this one case, there is no need for a pointer from the struct net_device to an individual struct netpoll. A lock is introduced to protect the setting and clearing of the np_rx pointer. The pointer will only be cleared upon netpoll client module removal, and the lock should be uncontested. Signed-off-by: Jeff Moyer Signed-off-by: David S. Miller --- include/linux/netpoll.h | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index 388cd91bc7a..bcd0ac33f59 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -27,7 +27,8 @@ struct netpoll_info { spinlock_t poll_lock; int poll_owner; int rx_flags; - struct netpoll *np; + spinlock_t rx_lock; + struct netpoll *rx_np; /* netpoll that registered an rx_hook */ }; void netpoll_poll(struct netpoll *np); @@ -44,11 +45,19 @@ void netpoll_queue(struct sk_buff *skb); static inline int netpoll_rx(struct sk_buff *skb) { struct netpoll_info *npinfo = skb->dev->npinfo; + unsigned long flags; + int ret = 0; - if (!npinfo || !npinfo->rx_flags) + if (!npinfo || (!npinfo->rx_np && !npinfo->rx_flags)) return 0; - return npinfo->np && __netpoll_rx(skb); + spin_lock_irqsave(&npinfo->rx_lock, flags); + /* check rx_flags again with the lock held */ + if (npinfo->rx_flags && __netpoll_rx(skb)) + ret = 1; + spin_unlock_irqrestore(&npinfo->rx_lock, flags); + + return ret; } static inline void netpoll_poll_lock(struct net_device *dev) -- cgit v1.2.3