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Commit 3710becf authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: RCU locking for simple ioctl() 



All ioctls() implemented by dev_ifsioc_locked() :
SIOCGIFFLAGS, SIOCGIFMETRIC, SIOCGIFMTU, SIOCGIFHWADDR,
SIOCGIFSLAVE, SIOCGIFMAP, SIOCGIFINDEX & SIOCGIFTXQLEN
can use RCU lock instead of dev_base_lock rwlock

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 685c7944

net/core/dev.c

+4 −4
Original line number Diff line number Diff line
@@ -4315,12 +4315,12 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa) 
EXPORT_SYMBOL(dev_set_mac_address);



/*

 *	Perform the SIOCxIFxxx calls, inside read_lock(dev_base_lock)

 *	Perform the SIOCxIFxxx calls, inside rcu_read_lock()

 */

static int dev_ifsioc_locked(struct net *net, struct ifreq *ifr, unsigned int cmd)

{

	int err;

	struct net_device *dev = __dev_get_by_name(net, ifr->ifr_name);

	struct net_device *dev = dev_get_by_name_rcu(net, ifr->ifr_name);



	if (!dev)

		return -ENODEV;
@@ -4552,9 +4552,9 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg) 
	case SIOCGIFINDEX:

	case SIOCGIFTXQLEN:

		dev_load(net, ifr.ifr_name);

		read_lock(&dev_base_lock);

		rcu_read_lock();

		ret = dev_ifsioc_locked(net, &ifr, cmd);

		read_unlock(&dev_base_lock);

		rcu_read_unlock();

		if (!ret) {

			if (colon)

				*colon = ':';