summaryrefslogtreecommitdiff
path: root/net/mctp
diff options
context:
space:
mode:
authorJeremy Kerr <jk@codeconstruct.com.au>2021-09-29 15:26:08 +0800
committerDavid S. Miller <davem@davemloft.net>2021-09-29 11:00:11 +0100
commit43f55f23f70881e9c397557f15c8090b368d0af2 (patch)
tree8fc42e6056ac109df1e6931763d31891d0f5e016 /net/mctp
parent73c618456dc5cf2acb597256d633060cf75de8d6 (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')
-rw-r--r--net/mctp/device.c25
-rw-r--r--net/mctp/neigh.c4
-rw-r--r--net/mctp/route.c4
3 files changed, 20 insertions, 13 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)
diff --git a/net/mctp/neigh.c b/net/mctp/neigh.c
index 90ed2f02d1fb..5cc042121493 100644
--- a/net/mctp/neigh.c
+++ b/net/mctp/neigh.c
@@ -47,7 +47,7 @@ static int mctp_neigh_add(struct mctp_dev *mdev, mctp_eid_t eid,
}
INIT_LIST_HEAD(&neigh->list);
neigh->dev = mdev;
- dev_hold(neigh->dev->dev);
+ mctp_dev_hold(neigh->dev);
neigh->eid = eid;
neigh->source = source;
memcpy(neigh->ha, lladdr, lladdr_len);
@@ -63,7 +63,7 @@ static void __mctp_neigh_free(struct rcu_head *rcu)
{
struct mctp_neigh *neigh = container_of(rcu, struct mctp_neigh, rcu);
- dev_put(neigh->dev->dev);
+ mctp_dev_put(neigh->dev);
kfree(neigh);
}
diff --git a/net/mctp/route.c b/net/mctp/route.c
index b2243b150e71..37aa67847a5a 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -455,7 +455,7 @@ static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb)
static void mctp_route_release(struct mctp_route *rt)
{
if (refcount_dec_and_test(&rt->refs)) {
- dev_put(rt->dev->dev);
+ mctp_dev_put(rt->dev);
kfree_rcu(rt, rcu);
}
}
@@ -815,7 +815,7 @@ static int mctp_route_add(struct mctp_dev *mdev, mctp_eid_t daddr_start,
rt->max = daddr_start + daddr_extent;
rt->mtu = mtu;
rt->dev = mdev;
- dev_hold(rt->dev->dev);
+ mctp_dev_hold(rt->dev);
rt->type = type;
rt->output = rtfn;