Commit b9067f5d authored by Arnd Bergmann's avatar Arnd Bergmann Committed by David S. Miller
Browse files

net: split out SIOCDEVPRIVATE handling from dev_ioctl 



SIOCDEVPRIVATE ioctl commands are mainly used in really old
drivers, and they have a number of problems:

- They hide behind the normal .ndo_do_ioctl function that
  is also used for other things in modern drivers, so it's
  hard to spot a driver that actually uses one of these

- Since drivers use a number different calling conventions,
  it is impossible to support compat mode for them in
  a generic way.

- With all drivers using the same 16 commands codes, there
  is no way to introspect the data being passed through
  things like strace.

Add a new net_device_ops callback pointer, to address the
first two of these. Separating them from .ndo_do_ioctl
makes it easy to grep for drivers with a .ndo_siocdevprivate
callback, and the unwieldy name hopefully makes it easier
to spot in code review.

By passing the ifreq structure and the ifr_data pointer
separately, it is no longer necessary to overload these,
and the driver can use either one for a given command.

Cc: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2fba2eae

Documentation/networking/netdevices.rst

+7 −0
Original line number Diff line number Diff line
@@ -222,6 +222,13 @@ ndo_do_ioctl: 
	Synchronization: rtnl_lock() semaphore.

	Context: process



ndo_siocdevprivate:

	Synchronization: rtnl_lock() semaphore.

	Context: process



	This is used to implement SIOCDEVPRIVATE ioctl helpers.

	These should not be added to new drivers, so don't use.



ndo_get_stats:

	Synchronization: rtnl_lock() semaphore, dev_base_lock rwlock, or RCU.

	Context: atomic (can't sleep under rwlock or RCU)

include/linux/netdevice.h

+3 −0
Original line number Diff line number Diff line
@@ -1361,6 +1361,9 @@ struct net_device_ops { 
	int			(*ndo_validate_addr)(struct net_device *dev);

	int			(*ndo_do_ioctl)(struct net_device *dev,

					        struct ifreq *ifr, int cmd);

	int			(*ndo_siocdevprivate)(struct net_device *dev,

						      struct ifreq *ifr,

						      void __user *data, int cmd);

	int			(*ndo_set_config)(struct net_device *dev,

					          struct ifmap *map);

	int			(*ndo_change_mtu)(struct net_device *dev,

net/core/dev_ioctl.c

+22 −3
Original line number Diff line number Diff line
@@ -259,6 +259,23 @@ static int dev_do_ioctl(struct net_device *dev, 
	return err;

}



static int dev_siocdevprivate(struct net_device *dev,

			      struct ifreq *ifr, unsigned int cmd)

{

	const struct net_device_ops *ops = dev->netdev_ops;

	void __user *data = ifr->ifr_data;



	if (ops->ndo_siocdevprivate) {

		if (netif_device_present(dev))

			return ops->ndo_siocdevprivate(dev, ifr, data, cmd);

		else

			return -ENODEV;

	}



	/* fall back to do_ioctl for drivers not yet converted */

	return dev_do_ioctl(dev, ifr, cmd);

}



/*

 *	Perform the SIOCxIFxxx calls, inside rtnl_lock()

 */
@@ -336,9 +353,11 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd) 
	 *	Unknown or private ioctl

	 */

	default:

		if ((cmd >= SIOCDEVPRIVATE &&

		    cmd <= SIOCDEVPRIVATE + 15) ||

		    cmd == SIOCBONDENSLAVE ||

		if (cmd >= SIOCDEVPRIVATE &&

		    cmd <= SIOCDEVPRIVATE + 15)

			return dev_siocdevprivate(dev, ifr, cmd);



		if (cmd == SIOCBONDENSLAVE ||

		    cmd == SIOCBONDRELEASE ||

		    cmd == SIOCBONDSETHWADDR ||

		    cmd == SIOCBONDSLAVEINFOQUERY ||