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From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com,
	Eric Dumazet <edumazet@google.com>
Subject: [PATCH v2 net-next 11/19] ip6mr: do not acquire mrt_lock in pim6_rcv()
Date: Thu, 23 Jun 2022 04:34:41 +0000	[thread overview]
Message-ID: <20220623043449.1217288-12-edumazet@google.com> (raw)
In-Reply-To: <20220623043449.1217288-1-edumazet@google.com>

rcu_read_lock() protection is more than enough.

vif_dev_read() supports either mrt_lock or rcu_read_lock().

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv6/ip6mr.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index a6d97952bf5306c245996c612107d0c851bbc822..fa6720377e82d732ccafa02b37cc28e0ab1cea07 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -559,12 +559,11 @@ static int pim6_rcv(struct sk_buff *skb)
 
 	if (ip6mr_fib_lookup(net, &fl6, &mrt) < 0)
 		goto drop;
-	reg_vif_num = mrt->mroute_reg_vif_num;
 
-	read_lock(&mrt_lock);
+	/* Pairs with WRITE_ONCE() in mif6_add()/mif6_delete() */
+	reg_vif_num = READ_ONCE(mrt->mroute_reg_vif_num);
 	if (reg_vif_num >= 0)
 		reg_dev = vif_dev_read(&mrt->vif_table[reg_vif_num]);
-	read_unlock(&mrt_lock);
 
 	if (!reg_dev)
 		goto drop;
-- 
2.37.0.rc0.104.g0611611a94-goog


  parent reply	other threads:[~2022-06-23  4:41 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-23  4:34 [PATCH v2 net-next 00/19] ipmr: get rid of rwlocks Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 01/19] ip6mr: do not get a device reference in pim6_rcv() Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 02/19] ipmr: add rcu protection over (struct vif_device)->dev Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 03/19] ipmr: change igmpmsg_netlink_event() prototype Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 04/19] ipmr: ipmr_cache_report() changes Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 05/19] ipmr: do not acquire mrt_lock in __pim_rcv() Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 06/19] ipmr: do not acquire mrt_lock in ioctl(SIOCGETVIFCNT) Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 07/19] ipmr: do not acquire mrt_lock before calling ipmr_cache_unresolved() Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 08/19] ipmr: do not acquire mrt_lock while calling ip_mr_forward() Eric Dumazet
2022-07-22 19:34   ` Vladimir Oltean
2022-07-22 20:37     ` Eric Dumazet
2022-07-22 21:10       ` Vladimir Oltean
2022-07-22 21:15         ` Vladimir Oltean
2022-06-23  4:34 ` [PATCH v2 net-next 09/19] ipmr: do not acquire mrt_lock in ipmr_get_route() Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 10/19] ip6mr: ip6mr_cache_report() changes Eric Dumazet
2022-06-23  4:34 ` Eric Dumazet [this message]
2022-06-23  4:34 ` [PATCH v2 net-next 12/19] ip6mr: do not acquire mrt_lock in ioctl(SIOCGETMIFCNT_IN6) Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 13/19] ip6mr: do not acquire mrt_lock before calling ip6mr_cache_unresolved Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 14/19] ip6mr: do not acquire mrt_lock while calling ip6_mr_forward() Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 15/19] ip6mr: switch ip6mr_get_route() to rcu_read_lock() Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 16/19] ipmr: adopt rcu_read_lock() in mr_dump() Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 17/19] ipmr: convert /proc handlers to rcu_read_lock() Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 18/19] ipmr: convert mrt_lock to a spinlock Eric Dumazet
2022-06-23  4:34 ` [PATCH v2 net-next 19/19] ip6mr: " Eric Dumazet
2022-06-24 10:50 ` [PATCH v2 net-next 00/19] ipmr: get rid of rwlocks patchwork-bot+netdevbpf

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