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[request,for,stable,inclusion] ipv6: reallocate addrconf router for ipv6 address when lo device up

Message ID 1402553851-8944-1-git-send-email-chenweilong@huawei.com
State Not Applicable, archived
Delegated to: David Miller
Headers show

Commit Message

chenweilong June 12, 2014, 6:17 a.m. UTC 
From: Weilong Chen <chenweilong@huawei.com>

"commit 33d99113b1102c2d2f8603b9ba72d89d915c13f5
ipv6: reallocate addrconf router for ipv6 address when lo device up."
This commit don't have a stable tag, but it fix the bug
no reply after loopback down-up.I think it should be
applied to stable 3.4.x kernels.

The bug is 67951 on bugzilla
https://bugzilla.kernel.org/show_bug.cgi?id=67951

The patch can't be applied directly. And it used the function introduced
by "commit 94e187c0" ip6_rt_put(), this patch can't be applied directly
either. 

Signed-off-by: Weilong Chen <chenweilong@huawei.com>
---
 include/net/ip6_fib.h |  9 +++++++++
 net/ipv6/addrconf.c   | 14 ++++++++++++--
 2 files changed, 21 insertions(+), 2 deletions(-)
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Patch

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 0ae759a..7c17c35 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -171,6 +171,15 @@  static inline void rt6_set_from(struct rt6_info *rt, struct rt6_info *from)
 	dst_hold(new);
 }
 
+static inline void ip6_rt_put(struct rt6_info *rt)
+{
+	/* dst_release() accepts a NULL parameter.
+	 * We rely on dst being first structure in struct rt6_info
+	 */
+	BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
+	dst_release(&rt->dst);
+}
+
 struct fib6_walker_t {
 	struct list_head lh;
 	struct fib6_node *root, *node;
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 9b8c3c6..00a0904 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2424,8 +2424,18 @@  static void init_loopback(struct net_device *dev)
 			if (sp_ifa->flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE))
 				continue;
 
-			if (sp_ifa->rt)
-				continue;
+			if (sp_ifa->rt) {
+				/* This dst has been added to garbage list when
+				 * lo device down, release this obsolete dst and
+				 * reallocate a new router for ifa.
+				 */
+				if (sp_ifa->rt->dst.obsolete > 0) {
+					ip6_rt_put(sp_ifa->rt);
+					sp_ifa->rt = NULL;
+				} else {
+					continue;
+				}
+			}
 
 			sp_rt = addrconf_dst_alloc(idev, &sp_ifa->addr, 0);