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| author | Jeff Moyer <jmoyer@redhat.com> | 2005-06-22 22:05:59 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2005-06-22 22:05:59 -0700 |
| commit | fbeec2e1552949002065435c9829dc244ad85407 (patch) | |
| tree | d97dc663bbef4bf59a1858b23a327f14043c33d1 /include/linux/netpoll.h | |
| parent | 115c1d6e61b70851d9a363328c3b8d4c2559a1d3 (diff) | |
| download | lwn-fbeec2e1552949002065435c9829dc244ad85407.tar.gz lwn-fbeec2e1552949002065435c9829dc244ad85407.zip | |
[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 <jmoyer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/netpoll.h')
| -rw-r--r-- | include/linux/netpoll.h | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index 388cd91bc7a6..bcd0ac33f592 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) |