linux/include/net/mctpdevice.h
Jeremy Kerr 43f55f23f7 mctp: Add refcounts to mctp_dev
Currently, we tie the struct mctp_dev lifetime to the underlying struct
net_device, and hold/put that device as a proxy for a separate mctp_dev
refcount. This works because we're not holding any references to the
mctp_dev that are different from the netdev lifetime.

In a future change we'll break that assumption though, as we'll need to
hold mctp_dev references in a workqueue, which might live past the
netdev unregister notification.

In order to support that, this change introduces a refcount on the
mctp_dev, currently taken by the net_device->mctp_ptr reference, and
released on netdev unregister events. We can then use this for future
references that might outlast the net device.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-29 11:00:11 +01:00

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C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Management Component Transport Protocol (MCTP) - device
* definitions.
*
* Copyright (c) 2021 Code Construct
* Copyright (c) 2021 Google
*/
#ifndef __NET_MCTPDEVICE_H
#define __NET_MCTPDEVICE_H
#include <linux/list.h>
#include <linux/types.h>
#include <linux/refcount.h>
struct mctp_dev {
struct net_device *dev;
refcount_t refs;
unsigned int net;
/* Only modified under RTNL. Reads have addrs_lock held */
u8 *addrs;
size_t num_addrs;
spinlock_t addrs_lock;
struct rcu_head rcu;
};
#define MCTP_INITIAL_DEFAULT_NET 1
struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev);
struct mctp_dev *__mctp_dev_get(const struct net_device *dev);
void mctp_dev_hold(struct mctp_dev *mdev);
void mctp_dev_put(struct mctp_dev *mdev);
#endif /* __NET_MCTPDEVICE_H */