Introduce __netpoll_setup_hold() which wraps __netpoll_setup() and on success holds a reference to the device. This helper requires caller to already hold RNTL and should be paired with netpoll_cleanup to ensure proper handling of the reference.
This helper is going to be used by netconsole to setup netpoll in response to a NETDEV_UP event. Since netconsole always perform cleanup using netpoll_cleanup, this will ensure that reference counting is correct and handled entirely inside netpoll.
Signed-off-by: Andre Carvalho asantostc@gmail.com --- include/linux/netpoll.h | 1 + net/core/netpoll.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+)
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index f22eec466040..345e74112674 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -69,6 +69,7 @@ static inline void netpoll_poll_enable(struct net_device *dev) { return; }
int netpoll_send_udp(struct netpoll *np, const char *msg, int len); int __netpoll_setup(struct netpoll *np, struct net_device *ndev); +int __netpoll_setup_hold(struct netpoll *np, struct net_device *ndev); int netpoll_setup(struct netpoll *np); void __netpoll_free(struct netpoll *np); void netpoll_cleanup(struct netpoll *np); diff --git a/net/core/netpoll.c b/net/core/netpoll.c index c85f740065fc..4d25ba422d81 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -605,6 +605,26 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) } EXPORT_SYMBOL_GPL(__netpoll_setup);
+/* + * Wrapper around __netpoll_setup that holds a reference to the device. + * The caller must pair this with netpoll_cleanup() to release the reference. + */ +int __netpoll_setup_hold(struct netpoll *np, struct net_device *ndev) +{ + int err; + + ASSERT_RTNL(); + + err = __netpoll_setup(np, ndev); + if (err) + return err; + + netdev_hold(ndev, &np->dev_tracker, GFP_KERNEL); + + return 0; +} +EXPORT_SYMBOL_GPL(__netpoll_setup_hold); + /* * Returns a pointer to a string representation of the identifier used * to select the egress interface for the given netpoll instance. buf