Commit e154bb7a authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net-sysfs: convert netstat_show() to RCU 



dev_get_stats() can be called from RCU, there is no need
to acquire dev_base_lock.

Change dev_isalive() comment to reflect we no longer use
dev_base_lock from net/core/net-sysfs.c

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 004d1383

net/core/net-sysfs.c

+3 −3
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ static const char fmt_dec[] = "%d\n"; 
static const char fmt_ulong[] = "%lu\n";

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



/* Caller holds RTNL, RCU or dev_base_lock */

/* Caller holds RTNL or RCU */

static inline int dev_isalive(const struct net_device *dev)

{

	return READ_ONCE(dev->reg_state) <= NETREG_REGISTERED;
@@ -685,14 +685,14 @@ static ssize_t netstat_show(const struct device *d, 
	WARN_ON(offset > sizeof(struct rtnl_link_stats64) ||

		offset % sizeof(u64) != 0);



	read_lock(&dev_base_lock);

	rcu_read_lock();

	if (dev_isalive(dev)) {

		struct rtnl_link_stats64 temp;

		const struct rtnl_link_stats64 *stats = dev_get_stats(dev, &temp);



		ret = sysfs_emit(buf, fmt_u64, *(u64 *)(((u8 *)stats) + offset));

	}

	read_unlock(&dev_base_lock);

	rcu_read_unlock();

	return ret;

}