From 67b62f98a1de962277b60d77c0c208b76867dbae Mon Sep 17 00:00:00 2001 From: David Ahern Date: Mon, 17 Oct 2016 19:15:53 -0700 Subject: [PATCH] net: dev: Improve debug statements for adjacency tracking Adjacency code only has debugs for the insert case. Add debugs for the remove path and make both consistently worded to make it easier to follow the insert and removal with reference counts. In addition, change the BUG to a WARN_ON. A missing adjacency at removal time is not cause for a panic. Signed-off-by: David Ahern Signed-off-by: David S. Miller --- net/core/dev.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index c6bbf310d407..f55fb4536016 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5561,6 +5561,9 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev, if (adj) { adj->ref_nr += 1; + pr_debug("Insert adjacency: dev %s adj_dev %s adj->ref_nr %d\n", + dev->name, adj_dev->name, adj->ref_nr); + return 0; } @@ -5574,8 +5577,8 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev, adj->private = private; dev_hold(adj_dev); - pr_debug("dev_hold for %s, because of link added from %s to %s\n", - adj_dev->name, dev->name, adj_dev->name); + pr_debug("Insert adjacency: dev %s adj_dev %s adj->ref_nr %d; dev_hold on %s\n", + dev->name, adj_dev->name, adj->ref_nr, adj_dev->name); if (netdev_adjacent_is_neigh_list(dev, adj_dev, dev_list)) { ret = netdev_adjacent_sysfs_add(dev, adj_dev, dev_list); @@ -5614,17 +5617,22 @@ static void __netdev_adjacent_dev_remove(struct net_device *dev, { struct netdev_adjacent *adj; + pr_debug("Remove adjacency: dev %s adj_dev %s ref_nr %d\n", + dev->name, adj_dev->name, ref_nr); + adj = __netdev_find_adj(adj_dev, dev_list); if (!adj) { - pr_err("tried to remove device %s from %s\n", + pr_err("Adjacency does not exist for device %s from %s\n", dev->name, adj_dev->name); - BUG(); + WARN_ON(1); + return; } if (adj->ref_nr > ref_nr) { - pr_debug("%s to %s ref_nr-%d = %d\n", dev->name, adj_dev->name, - ref_nr, adj->ref_nr-ref_nr); + pr_debug("adjacency: %s to %s ref_nr - %d = %d\n", + dev->name, adj_dev->name, ref_nr, + adj->ref_nr - ref_nr); adj->ref_nr -= ref_nr; return; } @@ -5636,7 +5644,7 @@ static void __netdev_adjacent_dev_remove(struct net_device *dev, netdev_adjacent_sysfs_del(dev, adj_dev->name, dev_list); list_del_rcu(&adj->list); - pr_debug("dev_put for %s, because link removed from %s to %s\n", + pr_debug("adjacency: dev_put for %s, because link removed from %s to %s\n", adj_dev->name, dev->name, adj_dev->name); dev_put(adj_dev); kfree_rcu(adj, rcu); -- 2.30.2