[PATCH net-next 1/2] net: Avoid unnessary loop when master_idx is invalid in inet_select_addr
From: <hidden>
Date: 2017-03-07 14:57:00
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
From: Gao Feng <redacted> When master_idx is invalid, it is zero. It is unnecessary to iterate all netdevs. Because l3mdev_master_ifindex_rcu(dev) != master_idx must be true. Now put this loop into the condition block when master_idx is valid. Signed-off-by: Gao Feng <redacted> --- net/ipv4/devinet.c | 68 +++++++++++++++++++++++++++++------------------------- 1 file changed, 36 insertions(+), 32 deletions(-)
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 5d367b7..1a9e550 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c@@ -1219,42 +1219,46 @@ __be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope) no_in_dev: master_idx = l3mdev_master_ifindex_rcu(dev); - /* For VRFs, the VRF device takes the place of the loopback device, - * with addresses on it being preferred. Note in such cases the - * loopback device will be among the devices that fail the master_idx - * equality check in the loop below. - */ - if (master_idx && - (dev = dev_get_by_index_rcu(net, master_idx)) && - (in_dev = __in_dev_get_rcu(dev))) { - for_primary_ifa(in_dev) { - if (ifa->ifa_scope != RT_SCOPE_LINK && - ifa->ifa_scope <= scope) { - addr = ifa->ifa_local; - goto out_unlock; + if (master_idx) { + /* For VRFs, the VRF device takes the place of the loopback device, + * with addresses on it being preferred. Note in such cases the + * loopback device will be among the devices that fail the master_idx + * equality check in the loop below. + */ + dev = dev_get_by_index_rcu(net, master_idx); + if (dev) { + in_dev = __in_dev_get_rcu(dev); + if (in_dev) { + for_primary_ifa(in_dev) { + if (ifa->ifa_scope != RT_SCOPE_LINK && + ifa->ifa_scope <= scope) { + addr = ifa->ifa_local; + goto out_unlock; + } + } endfor_ifa(in_dev); } - } endfor_ifa(in_dev); - } + } - /* Not loopback addresses on loopback should be preferred - in this case. It is important that lo is the first interface - in dev_base list. - */ - for_each_netdev_rcu(net, dev) { - if (l3mdev_master_ifindex_rcu(dev) != master_idx) - continue; + /* Not loopback addresses on loopback should be preferred + in this case. It is important that lo is the first interface + in dev_base list. + */ + for_each_netdev_rcu(net, dev) { + if (l3mdev_master_ifindex_rcu(dev) != master_idx) + continue; - in_dev = __in_dev_get_rcu(dev); - if (!in_dev) - continue; + in_dev = __in_dev_get_rcu(dev); + if (!in_dev) + continue; - for_primary_ifa(in_dev) { - if (ifa->ifa_scope != RT_SCOPE_LINK && - ifa->ifa_scope <= scope) { - addr = ifa->ifa_local; - goto out_unlock; - } - } endfor_ifa(in_dev); + for_primary_ifa(in_dev) { + if (ifa->ifa_scope != RT_SCOPE_LINK && + ifa->ifa_scope <= scope) { + addr = ifa->ifa_local; + goto out_unlock; + } + } endfor_ifa(in_dev); + } } out_unlock: rcu_read_unlock();
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1.9.1