Commit fe30937b authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

bonding: fix bond_get_stats() 



bond_get_stats() can be called from rtnetlink (with RTNL held)
or from /proc/net/dev seq handler (with RCU held)

The logic added in commit 5f0c5f73 ("bonding: make global bonding
stats more reliable") kind of assumed only one cpu could run there.

If multiple threads are reading /proc/net/dev, stats can be really
messed up after a while.

A second problem is that some fields are 32bit, so we need to properly
handle the wrap around problem.

Given that RTNL is not always held, we need to use
bond_for_each_slave_rcu().

Fixes: 5f0c5f73 ("bonding: make global bonding stats more reliable")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Andy Gospodarek <gospo@cumulusnetworks.com>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Reviewed-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent eee57723

drivers/net/bonding/bond_main.c

+35 −31
Original line number Diff line number Diff line
@@ -3301,6 +3301,30 @@ static int bond_close(struct net_device *bond_dev) 
	return 0;

}



/* fold stats, assuming all rtnl_link_stats64 fields are u64, but

 * that some drivers can provide 32bit values only.

 */

static void bond_fold_stats(struct rtnl_link_stats64 *_res,

			    const struct rtnl_link_stats64 *_new,

			    const struct rtnl_link_stats64 *_old)

{

	const u64 *new = (const u64 *)_new;

	const u64 *old = (const u64 *)_old;

	u64 *res = (u64 *)_res;

	int i;



	for (i = 0; i < sizeof(*_res) / sizeof(u64); i++) {

		u64 nv = new[i];

		u64 ov = old[i];



		/* detects if this particular field is 32bit only */

		if (((nv | ov) >> 32) == 0)

			res[i] += (u32)nv - (u32)ov;

		else

			res[i] += nv - ov;

	}

}



static struct rtnl_link_stats64 *bond_get_stats(struct net_device *bond_dev,

						struct rtnl_link_stats64 *stats)

{
@@ -3309,44 +3333,23 @@ static struct rtnl_link_stats64 *bond_get_stats(struct net_device *bond_dev, 
	struct list_head *iter;

	struct slave *slave;



	spin_lock(&bond->stats_lock);

	memcpy(stats, &bond->bond_stats, sizeof(*stats));



	bond_for_each_slave(bond, slave, iter) {

		const struct rtnl_link_stats64 *sstats =

	rcu_read_lock();

	bond_for_each_slave_rcu(bond, slave, iter) {

		const struct rtnl_link_stats64 *new =

			dev_get_stats(slave->dev, &temp);

		struct rtnl_link_stats64 *pstats = &slave->slave_stats;



		stats->rx_packets +=  sstats->rx_packets - pstats->rx_packets;

		stats->rx_bytes += sstats->rx_bytes - pstats->rx_bytes;

		stats->rx_errors += sstats->rx_errors - pstats->rx_errors;

		stats->rx_dropped += sstats->rx_dropped - pstats->rx_dropped;

		stats->rx_nohandler += sstats->rx_nohandler - pstats->rx_nohandler;



		stats->tx_packets += sstats->tx_packets - pstats->tx_packets;;

		stats->tx_bytes += sstats->tx_bytes - pstats->tx_bytes;

		stats->tx_errors += sstats->tx_errors - pstats->tx_errors;

		stats->tx_dropped += sstats->tx_dropped - pstats->tx_dropped;



		stats->multicast += sstats->multicast - pstats->multicast;

		stats->collisions += sstats->collisions - pstats->collisions;



		stats->rx_length_errors += sstats->rx_length_errors - pstats->rx_length_errors;

		stats->rx_over_errors += sstats->rx_over_errors - pstats->rx_over_errors;

		stats->rx_crc_errors += sstats->rx_crc_errors - pstats->rx_crc_errors;

		stats->rx_frame_errors += sstats->rx_frame_errors - pstats->rx_frame_errors;

		stats->rx_fifo_errors += sstats->rx_fifo_errors - pstats->rx_fifo_errors;

		stats->rx_missed_errors += sstats->rx_missed_errors - pstats->rx_missed_errors;



		stats->tx_aborted_errors += sstats->tx_aborted_errors - pstats->tx_aborted_errors;

		stats->tx_carrier_errors += sstats->tx_carrier_errors - pstats->tx_carrier_errors;

		stats->tx_fifo_errors += sstats->tx_fifo_errors - pstats->tx_fifo_errors;

		stats->tx_heartbeat_errors += sstats->tx_heartbeat_errors - pstats->tx_heartbeat_errors;

		stats->tx_window_errors += sstats->tx_window_errors - pstats->tx_window_errors;



		bond_fold_stats(stats, new, &slave->slave_stats);



		/* save off the slave stats for the next run */

		memcpy(pstats, sstats, sizeof(*sstats));

		memcpy(&slave->slave_stats, new, sizeof(*new));

	}

	rcu_read_unlock();



	memcpy(&bond->bond_stats, stats, sizeof(*stats));

	spin_unlock(&bond->stats_lock);



	return stats;

}
@@ -4160,6 +4163,7 @@ void bond_setup(struct net_device *bond_dev) 
	struct bonding *bond = netdev_priv(bond_dev);



	spin_lock_init(&bond->mode_lock);

	spin_lock_init(&bond->stats_lock);

	bond->params = bonding_defaults;



	/* Initialize pointers */

include/net/bonding.h

+1 −0
Original line number Diff line number Diff line
@@ -215,6 +215,7 @@ struct bonding { 
	 * ALB mode (6) - to sync the use and modifications of its hash table

	 */

	spinlock_t mode_lock;

	spinlock_t stats_lock;

	u8	 send_peer_notif;

	u8       igmp_retrans;

#ifdef CONFIG_PROC_FS

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