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From: Taehee Yoo <ap420073@gmail.com>
To: daniel@iogearbox.net, ast@kernel.org
Cc: netdev@vger.kernel.org, ap420073@gmail.com
Subject: [PATCH bpf-next] lwt_bpf: remove unnecessary rcu_read_lock in run_lwt_bpf
Date: Mon, 30 Jul 2018 22:22:59 +0900	[thread overview]
Message-ID: <20180730132259.6338-1-ap420073@gmail.com> (raw)

run_lwt_bpf is called by bpf_{input/output/xmit}.
These functions are already protected by rcu_read_lock.
because lwtunnel_{input/output/xmit} holds rcu_read_lock
and then calls bpf_{input/output/xmit}.
So that rcu_read_lock in the run_lwt_bpf is unnecessary.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
---
 net/core/lwt_bpf.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c
index e7e626f..a49c7ba 100644
--- a/net/core/lwt_bpf.c
+++ b/net/core/lwt_bpf.c
@@ -50,10 +50,8 @@ static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt,
 	 * mixing with BH RCU lock doesn't work.
 	 */
 	preempt_disable();
-	rcu_read_lock();
 	bpf_compute_data_pointers(skb);
 	ret = bpf_prog_run_save_cb(lwt->prog, skb);
-	rcu_read_unlock();
 
 	switch (ret) {
 	case BPF_OK:
-- 
2.9.3

             reply	other threads:[~2018-07-30 14:58 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-30 13:22 Taehee Yoo [this message]
2018-07-30 22:22 ` [PATCH bpf-next] lwt_bpf: remove unnecessary rcu_read_lock in run_lwt_bpf Y Song
2018-07-31  7:27 ` Daniel Borkmann

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