netdev - [PATCH AUTOSEL 4.19 3/4] netfilter: nf_tables: add rescheduling points during loop detection walks

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Date:   Mon,  1 Aug 2022 15:03:30 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Florian Westphal <fw@...len.de>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Sasha Levin <sashal@...nel.org>, kadlec@...filter.org,
        davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        pabeni@...hat.com, netfilter-devel@...r.kernel.org,
        coreteam@...filter.org, netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 3/4] netfilter: nf_tables: add rescheduling points during loop detection walks

From: Florian Westphal <fw@...len.de>

[ Upstream commit 81ea010667417ef3f218dfd99b69769fe66c2b67 ]

Add explicit rescheduling points during ruleset walk.

Switching to a faster algorithm is possible but this is a much
smaller change, suitable for nf tree.

Link: https://bugzilla.netfilter.org/show_bug.cgi?id=1460
Signed-off-by: Florian Westphal <fw@...len.de>
Acked-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/netfilter/nf_tables_api.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index ab68076d2cba..a50cdd92f33f 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2550,6 +2550,8 @@ int nft_chain_validate(const struct nft_ctx *ctx, const struct nft_chain *chain)
 			if (err < 0)
 				return err;
 		}
+
+		cond_resched();
 	}
 
 	return 0;
@@ -6907,9 +6909,13 @@ static int nf_tables_check_loops(const struct nft_ctx *ctx,
 				break;
 			}
 		}
+
+		cond_resched();
 	}
 
 	list_for_each_entry(set, &ctx->table->sets, list) {
+		cond_resched();
+
 		if (!nft_is_active_next(ctx->net, set))
 			continue;
 		if (!(set->flags & NFT_SET_MAP) ||
-- 
2.35.1