Commit 12692e3d authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net-sysfs: convert netdev_show() to RCU 



Make clear dev_isalive() can be called with RCU protection.

Then convert netdev_show() to RCU, to remove dev_base_lock
dependency.

Also add RCU to broadcast_show().

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4d42b37d

net/core/net-sysfs.c

+10 −7
Original line number Diff line number Diff line
@@ -34,10 +34,10 @@ static const char fmt_dec[] = "%d\n"; 
static const char fmt_ulong[] = "%lu\n";

static const char fmt_u64[] = "%llu\n";



/* Caller holds RTNL or dev_base_lock */

/* Caller holds RTNL, RCU or dev_base_lock */

static inline int dev_isalive(const struct net_device *dev)

{

	return dev->reg_state <= NETREG_REGISTERED;

	return READ_ONCE(dev->reg_state) <= NETREG_REGISTERED;

}



/* use same locking rules as GIF* ioctl's */
@@ -48,10 +48,10 @@ static ssize_t netdev_show(const struct device *dev, 
	struct net_device *ndev = to_net_dev(dev);

	ssize_t ret = -EINVAL;



	read_lock(&dev_base_lock);

	rcu_read_lock();

	if (dev_isalive(ndev))

		ret = (*format)(ndev, buf);

	read_unlock(&dev_base_lock);

	rcu_read_unlock();



	return ret;

}
@@ -60,7 +60,7 @@ static ssize_t netdev_show(const struct device *dev, 
#define NETDEVICE_SHOW(field, format_string)				\

static ssize_t format_##field(const struct net_device *dev, char *buf)	\

{									\

	return sysfs_emit(buf, format_string, dev->field);		\

	return sysfs_emit(buf, format_string, READ_ONCE(dev->field));		\

}									\

static ssize_t field##_show(struct device *dev,				\

			    struct device_attribute *attr, char *buf)	\
@@ -161,10 +161,13 @@ static ssize_t broadcast_show(struct device *dev, 
			      struct device_attribute *attr, char *buf)

{

	struct net_device *ndev = to_net_dev(dev);

	int ret = -EINVAL;



	rcu_read_lock();

	if (dev_isalive(ndev))

		return sysfs_format_mac(buf, ndev->broadcast, ndev->addr_len);

	return -EINVAL;

		ret = sysfs_format_mac(buf, ndev->broadcast, ndev->addr_len);

	rcu_read_unlock();

	return ret;

}

static DEVICE_ATTR_RO(broadcast);