netfilter: nft_flow_offload: wait for garbage collector to run after cleanup

Web:        https://git.kernel.org/torvalds/c/c7f0030b5b67866c588845abde7bf011de25b98a
Commit:     c7f0030b5b67866c588845abde7bf011de25b98a
Parent:     ba7cd5d95f25cc6005f687dabdb4e7a6063adda9
Refname:    refs/heads/master
Author:     Pablo Neira Ayuso <[email protected]>
AuthorDate: Thu Feb 1 18:49:00 2018 +0100
Committer:  Pablo Neira Ayuso <[email protected]>
CommitDate: Fri Feb 2 18:26:42 2018 +0100

    netfilter: nft_flow_offload: wait for garbage collector to run after cleanup
    
    If netdevice goes down, then flowtable entries are scheduled to be
    removed. Wait for garbage collector to have a chance to run so it can
    delete them from the hashtable.
    
    The flush call might sleep, so hold the nfnl mutex from
    nft_flow_table_iterate() instead of rcu read side lock. The use of the
    nfnl mutex is also implicitly fixing races between updates via nfnetlink
    and netdevice event.
    
    Signed-off-by: Pablo Neira Ayuso <[email protected]>
---
 net/netfilter/nf_tables_api.c    | 8 ++++----
 net/netfilter/nft_flow_offload.c | 1 +
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 0791813a1e7d..07dd1fac78a8 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5006,13 +5006,13 @@ void nft_flow_table_iterate(struct net *net,
 	struct nft_flowtable *flowtable;
 	const struct nft_table *table;
 
-	rcu_read_lock();
-	list_for_each_entry_rcu(table, &net->nft.tables, list) {
-		list_for_each_entry_rcu(flowtable, &table->flowtables, list) {
+	nfnl_lock(NFNL_SUBSYS_NFTABLES);
+	list_for_each_entry(table, &net->nft.tables, list) {
+		list_for_each_entry(flowtable, &table->flowtables, list) {
 			iter(&flowtable->data, data);
 		}
 	}
-	rcu_read_unlock();
+	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
 }
 EXPORT_SYMBOL_GPL(nft_flow_table_iterate);
 
diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index 4503b8dcf9c0..1739ff8ca21f 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -208,6 +208,7 @@ static void nft_flow_offload_iterate_cleanup(struct nf_flowtable *flowtable,
 					     void *data)
 {
 	nf_flow_table_iterate(flowtable, flow_offload_iterate_cleanup, data);
+	flush_delayed_work(&flowtable->gc_work);
 }
 
 static int flow_offload_netdev_event(struct notifier_block *this,
--
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