[SRU][F:linux-bluefield][PATCH 3/7] net: sched: refactor police action helpers to require tcf_lock

Bodong Wang bodong at nvidia.com
Tue Aug 3 19:16:05 UTC 2021


From: Vlad Buslov <vladbu at mellanox.com>

BugLink: https://bugs.launchpad.net/bugs/1938818

In order to remove rtnl lock dependency from flow_action representation
translator, change rcu_dereference_bh_rtnl() to rcu_dereference_protected()
in police action helpers that provide external access to rate and burst
values. This is safe to do because the functions are not called from
anywhere else outside flow_action infrastructure which was modified to
obtain tcf_lock when accessing action data in one of previous patches in
the series.

Signed-off-by: Vlad Buslov <vladbu at mellanox.com>
Acked-by: Jiri Pirko <jiri at mellanox.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit 487e9589cc0ebebde4d1c4764aab271e5680a6b6)
Signed-off-by: Bodong Wang <bodong at nvidia.com>
---
 include/net/tc_act/tc_police.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/net/tc_act/tc_police.h b/include/net/tc_act/tc_police.h
index 9bb9b05..cd973b1 100644
--- a/include/net/tc_act/tc_police.h
+++ b/include/net/tc_act/tc_police.h
@@ -54,7 +54,8 @@ static inline u64 tcf_police_rate_bytes_ps(const struct tc_action *act)
 	struct tcf_police *police = to_police(act);
 	struct tcf_police_params *params;
 
-	params = rcu_dereference_bh_rtnl(police->params);
+	params = rcu_dereference_protected(police->params,
+					   lockdep_is_held(&police->tcf_lock));
 	return params->rate.rate_bytes_ps;
 }
 
@@ -63,7 +64,8 @@ static inline s64 tcf_police_tcfp_burst(const struct tc_action *act)
 	struct tcf_police *police = to_police(act);
 	struct tcf_police_params *params;
 
-	params = rcu_dereference_bh_rtnl(police->params);
+	params = rcu_dereference_protected(police->params,
+					   lockdep_is_held(&police->tcf_lock));
 	return params->tcfp_burst;
 }
 
-- 
1.8.3.1




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