diff options
| author | Jeremy Kerr <jk@codeconstruct.com.au> | 2021-09-29 15:26:08 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-09-29 11:00:11 +0100 |
| commit | 43f55f23f70881e9c397557f15c8090b368d0af2 (patch) | |
| tree | 8fc42e6056ac109df1e6931763d31891d0f5e016 /net/mctp/device.c | |
| parent | 73c618456dc5cf2acb597256d633060cf75de8d6 (diff) | |
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>
Diffstat (limited to 'net/mctp/device.c')
| -rw-r--r-- | net/mctp/device.c | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/net/mctp/device.c b/net/mctp/device.c index c34963974cc1..f556c6d01abc 100644 --- a/net/mctp/device.c +++ b/net/mctp/device.c @@ -35,14 +35,6 @@ struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev) return rtnl_dereference(dev->mctp_ptr); } -static void mctp_dev_destroy(struct mctp_dev *mdev) -{ - struct net_device *dev = mdev->dev; - - dev_put(dev); - kfree_rcu(mdev, rcu); -} - static int mctp_fill_addrinfo(struct sk_buff *skb, struct netlink_callback *cb, struct mctp_dev *mdev, mctp_eid_t eid) { @@ -255,6 +247,19 @@ static int mctp_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, return 0; } +void mctp_dev_hold(struct mctp_dev *mdev) +{ + refcount_inc(&mdev->refs); +} + +void mctp_dev_put(struct mctp_dev *mdev) +{ + if (refcount_dec_and_test(&mdev->refs)) { + dev_put(mdev->dev); + kfree_rcu(mdev, rcu); + } +} + static struct mctp_dev *mctp_add_dev(struct net_device *dev) { struct mctp_dev *mdev; @@ -270,7 +275,9 @@ static struct mctp_dev *mctp_add_dev(struct net_device *dev) mdev->net = mctp_default_net(dev_net(dev)); /* associate to net_device */ + refcount_set(&mdev->refs, 1); rcu_assign_pointer(dev->mctp_ptr, mdev); + dev_hold(dev); mdev->dev = dev; @@ -345,7 +352,7 @@ static void mctp_unregister(struct net_device *dev) mctp_neigh_remove_dev(mdev); kfree(mdev->addrs); - mctp_dev_destroy(mdev); + mctp_dev_put(mdev); } static int mctp_register(struct net_device *dev) |