diff mbox series

[net-next,4/4] ipv4: add (struct uncached_list)->quarantine list

Message ID 20220210214231.2420942-5-eric.dumazet@gmail.com (mailing list archive)
State Accepted
Commit 29e5375d7fcb5f88b438d74d537bbfd67ac75a64
Delegated to: Netdev Maintainers
Headers show
Series ipv6: remove addrconf reliance on loopback | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/cc_maintainers warning 2 maintainers not CCed: dsahern@kernel.org yoshfuji@linux-ipv6.org
netdev/build_clang success Errors and warnings before: 18 this patch: 18
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch warning WARNING: Possible repeated word: 'can'
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Feb. 10, 2022, 9:42 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

This is an optimization to keep the per-cpu lists as short as possible:

Whenever rt_flush_dev() changes one rtable dst.dev
matching the disappearing device, it can can transfer the object
to a quarantine list, waiting for a final rt_del_uncached_list().

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/route.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 634766e6c7cc8a472e912f7d4e99bb6be0397bb6..202d6b1fff43fb095427720ec36fe3744aeb7149 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1485,6 +1485,7 @@  static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
 struct uncached_list {
 	spinlock_t		lock;
 	struct list_head	head;
+	struct list_head	quarantine;
 };
 
 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
@@ -1506,7 +1507,7 @@  void rt_del_uncached_list(struct rtable *rt)
 		struct uncached_list *ul = rt->rt_uncached_list;
 
 		spin_lock_bh(&ul->lock);
-		list_del(&rt->rt_uncached);
+		list_del_init(&rt->rt_uncached);
 		spin_unlock_bh(&ul->lock);
 	}
 }
@@ -1521,20 +1522,24 @@  static void ipv4_dst_destroy(struct dst_entry *dst)
 
 void rt_flush_dev(struct net_device *dev)
 {
-	struct rtable *rt;
+	struct rtable *rt, *safe;
 	int cpu;
 
 	for_each_possible_cpu(cpu) {
 		struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
 
+		if (list_empty(&ul->head))
+			continue;
+
 		spin_lock_bh(&ul->lock);
-		list_for_each_entry(rt, &ul->head, rt_uncached) {
+		list_for_each_entry_safe(rt, safe, &ul->head, rt_uncached) {
 			if (rt->dst.dev != dev)
 				continue;
 			rt->dst.dev = blackhole_netdev;
 			dev_replace_track(dev, blackhole_netdev,
 					  &rt->dst.dev_tracker,
 					  GFP_ATOMIC);
+			list_move(&rt->rt_uncached, &ul->quarantine);
 		}
 		spin_unlock_bh(&ul->lock);
 	}
@@ -3706,6 +3711,7 @@  int __init ip_rt_init(void)
 		struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
 
 		INIT_LIST_HEAD(&ul->head);
+		INIT_LIST_HEAD(&ul->quarantine);
 		spin_lock_init(&ul->lock);
 	}
 #ifdef CONFIG_IP_ROUTE_CLASSID