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 f22eec4660405eaa654eb7746cbfdc89113fe312..345e741126748c0ee8d55dba594d782bced4eeed 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 60a05d3b7c2491096f79ea6cf82eeef222c3eac2..bf563c4259f6cb19c31613ff277eb5a0e2165e43 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -608,6 +608,26 @@ 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
--
2.51.0