Commit 473f5e13 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'netdev-tracking' 

Jakub Kicinski says:

====================
net: create device lookup API with reference tracking

We still see dev_hold() / dev_put() calls without reference tracker
getting added in new code. dev_get_by_name() / dev_get_by_index()
seem to be one of the sources of those. Provide appropriate helpers.
Allocating the tracker can obviously be done with an additional call
to netdev_tracker_alloc(), but a single API feels cleaner.

v2:
 - fix a dev_put() in ethtool
v1: https://lore.kernel.org/all/20230609183207.1466075-1-kuba@kernel.org/


====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 89da780a 48eed027

include/linux/netdevice.h

+4 −0
Original line number Diff line number Diff line
@@ -3124,6 +3124,10 @@ struct net_device *netdev_sk_get_lowest_dev(struct net_device *dev, 
					    struct sock *sk);

struct net_device *dev_get_by_index(struct net *net, int ifindex);

struct net_device *__dev_get_by_index(struct net *net, int ifindex);

struct net_device *netdev_get_by_index(struct net *net, int ifindex,

				       netdevice_tracker *tracker, gfp_t gfp);

struct net_device *netdev_get_by_name(struct net *net, const char *name,

				      netdevice_tracker *tracker, gfp_t gfp);

struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex);

struct net_device *dev_get_by_napi_id(unsigned int napi_id);

int dev_restart(struct net_device *dev);

net/core/dev.c

+45 −18
Original line number Diff line number Diff line
@@ -758,29 +758,43 @@ struct net_device *dev_get_by_name_rcu(struct net *net, const char *name) 
}

EXPORT_SYMBOL(dev_get_by_name_rcu);



/* Deprecated for new users, call netdev_get_by_name() instead */

struct net_device *dev_get_by_name(struct net *net, const char *name)

{

	struct net_device *dev;



	rcu_read_lock();

	dev = dev_get_by_name_rcu(net, name);

	dev_hold(dev);

	rcu_read_unlock();

	return dev;

}

EXPORT_SYMBOL(dev_get_by_name);



/**

 *	dev_get_by_name		- find a device by its name

 *	netdev_get_by_name() - find a device by its name

 *	@net: the applicable net namespace

 *	@name: name to find

 *	@tracker: tracking object for the acquired reference

 *	@gfp: allocation flags for the tracker

 *

 *	Find an interface by name. This can be called from any

 *	context and does its own locking. The returned handle has

 *	the usage count incremented and the caller must use dev_put() to

 *	the usage count incremented and the caller must use netdev_put() to

 *	release it when it is no longer needed. %NULL is returned if no

 *	matching device is found.

 */



struct net_device *dev_get_by_name(struct net *net, const char *name)

struct net_device *netdev_get_by_name(struct net *net, const char *name,

				      netdevice_tracker *tracker, gfp_t gfp)

{

	struct net_device *dev;



	rcu_read_lock();

	dev = dev_get_by_name_rcu(net, name);

	dev_hold(dev);

	rcu_read_unlock();

	dev = dev_get_by_name(net, name);

	if (dev)

		netdev_tracker_alloc(dev, tracker, gfp);

	return dev;

}

EXPORT_SYMBOL(dev_get_by_name);

EXPORT_SYMBOL(netdev_get_by_name);



/**

 *	__dev_get_by_index - find a device by its ifindex
@@ -831,29 +845,42 @@ struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex) 
}

EXPORT_SYMBOL(dev_get_by_index_rcu);



/* Deprecated for new users, call netdev_get_by_index() instead */

struct net_device *dev_get_by_index(struct net *net, int ifindex)

{

	struct net_device *dev;



	rcu_read_lock();

	dev = dev_get_by_index_rcu(net, ifindex);

	dev_hold(dev);

	rcu_read_unlock();

	return dev;

}

EXPORT_SYMBOL(dev_get_by_index);



/**

 *	dev_get_by_index - find a device by its ifindex

 *	netdev_get_by_index() - find a device by its ifindex

 *	@net: the applicable net namespace

 *	@ifindex: index of device

 *	@tracker: tracking object for the acquired reference

 *	@gfp: allocation flags for the tracker

 *

 *	Search for an interface by index. Returns NULL if the device

 *	is not found or a pointer to the device. The device returned has

 *	had a reference added and the pointer is safe until the user calls

 *	dev_put to indicate they have finished with it.

 *	netdev_put() to indicate they have finished with it.

 */



struct net_device *dev_get_by_index(struct net *net, int ifindex)

struct net_device *netdev_get_by_index(struct net *net, int ifindex,

				       netdevice_tracker *tracker, gfp_t gfp)

{

	struct net_device *dev;



	rcu_read_lock();

	dev = dev_get_by_index_rcu(net, ifindex);

	dev_hold(dev);

	rcu_read_unlock();

	dev = dev_get_by_index(net, ifindex);

	if (dev)

		netdev_tracker_alloc(dev, tracker, gfp);

	return dev;

}

EXPORT_SYMBOL(dev_get_by_index);

EXPORT_SYMBOL(netdev_get_by_index);



/**

 *	dev_get_by_napi_id - find a device by napi_id

net/core/netpoll.c

+2 −3
Original line number Diff line number Diff line
@@ -690,7 +690,7 @@ int netpoll_setup(struct netpoll *np) 
		err = -ENODEV;

		goto unlock;

	}

	dev_hold(ndev);

	netdev_hold(ndev, &np->dev_tracker, GFP_KERNEL);



	if (netdev_master_upper_dev_get(ndev)) {

		np_err(np, "%s is a slave device, aborting\n", np->dev_name);
@@ -783,12 +783,11 @@ int netpoll_setup(struct netpoll *np) 
	err = __netpoll_setup(np, ndev);

	if (err)

		goto put;

	netdev_tracker_alloc(ndev, &np->dev_tracker, GFP_KERNEL);

	rtnl_unlock();

	return 0;



put:

	dev_put(ndev);

	netdev_put(ndev, &np->dev_tracker);

unlock:

	rtnl_unlock();

	return err;

net/ethtool/netlink.c

+5 −5
Original line number Diff line number Diff line
@@ -115,7 +115,8 @@ int ethnl_parse_header_dev_get(struct ethnl_req_info *req_info, 
	if (tb[ETHTOOL_A_HEADER_DEV_INDEX]) {

		u32 ifindex = nla_get_u32(tb[ETHTOOL_A_HEADER_DEV_INDEX]);



		dev = dev_get_by_index(net, ifindex);

		dev = netdev_get_by_index(net, ifindex, &req_info->dev_tracker,

					  GFP_KERNEL);

		if (!dev) {

			NL_SET_ERR_MSG_ATTR(extack,

					    tb[ETHTOOL_A_HEADER_DEV_INDEX],
@@ -125,13 +126,14 @@ int ethnl_parse_header_dev_get(struct ethnl_req_info *req_info, 
		/* if both ifindex and ifname are passed, they must match */

		if (devname_attr &&

		    strncmp(dev->name, nla_data(devname_attr), IFNAMSIZ)) {

			dev_put(dev);

			netdev_put(dev, &req_info->dev_tracker);

			NL_SET_ERR_MSG_ATTR(extack, header,

					    "ifindex and name do not match");

			return -ENODEV;

		}

	} else if (devname_attr) {

		dev = dev_get_by_name(net, nla_data(devname_attr));

		dev = netdev_get_by_name(net, nla_data(devname_attr),

					 &req_info->dev_tracker, GFP_KERNEL);

		if (!dev) {

			NL_SET_ERR_MSG_ATTR(extack, devname_attr,

					    "no device matches name");
@@ -144,8 +146,6 @@ int ethnl_parse_header_dev_get(struct ethnl_req_info *req_info, 
	}



	req_info->dev = dev;

	if (dev)

		netdev_tracker_alloc(dev, &req_info->dev_tracker, GFP_KERNEL);

	req_info->flags = flags;

	return 0;

}

net/ipv6/route.c

+6 −6
Original line number Diff line number Diff line
@@ -3503,6 +3503,7 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh, 
		 struct fib6_config *cfg, gfp_t gfp_flags,

		 struct netlink_ext_ack *extack)

{

	netdevice_tracker *dev_tracker = &fib6_nh->fib_nh_dev_tracker;

	struct net_device *dev = NULL;

	struct inet6_dev *idev = NULL;

	int addr_type;
@@ -3520,7 +3521,8 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh, 


	err = -ENODEV;

	if (cfg->fc_ifindex) {

		dev = dev_get_by_index(net, cfg->fc_ifindex);

		dev = netdev_get_by_index(net, cfg->fc_ifindex,

					  dev_tracker, gfp_flags);

		if (!dev)

			goto out;

		idev = in6_dev_get(dev);
@@ -3554,11 +3556,11 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh, 
		/* hold loopback dev/idev if we haven't done so. */

		if (dev != net->loopback_dev) {

			if (dev) {

				dev_put(dev);

				netdev_put(dev, dev_tracker);

				in6_dev_put(idev);

			}

			dev = net->loopback_dev;

			dev_hold(dev);

			netdev_hold(dev, dev_tracker, gfp_flags);

			idev = in6_dev_get(dev);

			if (!idev) {

				err = -ENODEV;
@@ -3610,8 +3612,6 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh, 
	}



	fib6_nh->fib_nh_dev = dev;

	netdev_tracker_alloc(dev, &fib6_nh->fib_nh_dev_tracker, gfp_flags);



	fib6_nh->fib_nh_oif = dev->ifindex;

	err = 0;

out:
@@ -3621,7 +3621,7 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh, 
	if (err) {

		lwtstate_put(fib6_nh->fib_nh_lws);

		fib6_nh->fib_nh_lws = NULL;

		dev_put(dev);

		netdev_put(dev, dev_tracker);

	}



	return err;