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Message-Id: <1489114366-7355-1-git-send-email-fgao@ikuai8.com>
Date: Fri, 10 Mar 2017 10:52:46 +0800
From: fgao@...ai8.com
To: davem@...emloft.net, kuznet@....inr.ac.ru, jmorris@...ei.org,
kaber@...sh.net, netdev@...r.kernel.org, gfree.wind@...il.com
Cc: Gao Feng <fgao@...ai8.com>
Subject: [PATCH v3 net-next 1/2] net: Avoid unnessary loop when master_idx is invalid in inet_select_addr
From: Gao Feng <fgao@...ai8.com>
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 <fgao@...ai8.com>
---
v3: Add the cover letter, per David
v2: Correct the comit log and remove useless braces, per Sergei
v1: Initial Version
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();
--
1.9.1
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