netdev - [PATCH net-next v2 14/15] net: core: protect rate estimator statistics pointer with lock

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Date:   Fri, 10 Aug 2018 20:51:54 +0300
From:   Vlad Buslov <vladbu@...lanox.com>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, jhs@...atatu.com, xiyou.wangcong@...il.com,
        jiri@...nulli.us, pablo@...filter.org, kadlec@...ckhole.kfki.hu,
        fw@...len.de, ast@...nel.org, daniel@...earbox.net,
        edumazet@...gle.com, keescook@...omium.org,
        marcelo.leitner@...il.com, Vlad Buslov <vladbu@...lanox.com>
Subject: [PATCH net-next v2 14/15] net: core: protect rate estimator statistics pointer with lock

Extend gen_new_estimator() to also take stats_lock when re-assigning rate
estimator statistics pointer. (to be used by unlocked actions)

Rename 'stats_lock' to 'lock' and change argument description to explain
that it is now also used for control path.

Signed-off-by: Vlad Buslov <vladbu@...lanox.com>
---
 include/net/gen_stats.h  |  4 ++--
 net/core/gen_estimator.c | 21 +++++++++++++--------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
index 0304ba2ae353..883bb9085f15 100644
--- a/include/net/gen_stats.h
+++ b/include/net/gen_stats.h
@@ -59,13 +59,13 @@ int gnet_stats_finish_copy(struct gnet_dump *d);
 int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 		      struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 		      struct net_rate_estimator __rcu **rate_est,
-		      spinlock_t *stats_lock,
+		      spinlock_t *lock,
 		      seqcount_t *running, struct nlattr *opt);
 void gen_kill_estimator(struct net_rate_estimator __rcu **ptr);
 int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
 			  struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 			  struct net_rate_estimator __rcu **ptr,
-			  spinlock_t *stats_lock,
+			  spinlock_t *lock,
 			  seqcount_t *running, struct nlattr *opt);
 bool gen_estimator_active(struct net_rate_estimator __rcu **ptr);
 bool gen_estimator_read(struct net_rate_estimator __rcu **ptr,
diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 98fd12721221..e4e442d70c2d 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -112,7 +112,7 @@ static void est_timer(struct timer_list *t)
  * @bstats: basic statistics
  * @cpu_bstats: bstats per cpu
  * @rate_est: rate estimator statistics
- * @stats_lock: statistics lock
+ * @lock: lock for statistics and control path
  * @running: qdisc running seqcount
  * @opt: rate estimator configuration TLV
  *
@@ -128,7 +128,7 @@ static void est_timer(struct timer_list *t)
 int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 		      struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 		      struct net_rate_estimator __rcu **rate_est,
-		      spinlock_t *stats_lock,
+		      spinlock_t *lock,
 		      seqcount_t *running,
 		      struct nlattr *opt)
 {
@@ -154,19 +154,22 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 	seqcount_init(&est->seq);
 	intvl_log = parm->interval + 2;
 	est->bstats = bstats;
-	est->stats_lock = stats_lock;
+	est->stats_lock = lock;
 	est->running  = running;
 	est->ewma_log = parm->ewma_log;
 	est->intvl_log = intvl_log;
 	est->cpu_bstats = cpu_bstats;
 
-	if (stats_lock)
+	if (lock)
 		local_bh_disable();
 	est_fetch_counters(est, &b);
-	if (stats_lock)
+	if (lock)
 		local_bh_enable();
 	est->last_bytes = b.bytes;
 	est->last_packets = b.packets;
+
+	if (lock)
+		spin_lock_bh(lock);
 	old = rcu_dereference_protected(*rate_est, 1);
 	if (old) {
 		del_timer_sync(&old->timer);
@@ -179,6 +182,8 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 	mod_timer(&est->timer, est->next_jiffies);
 
 	rcu_assign_pointer(*rate_est, est);
+	if (lock)
+		spin_unlock_bh(lock);
 	if (old)
 		kfree_rcu(old, rcu);
 	return 0;
@@ -209,7 +214,7 @@ EXPORT_SYMBOL(gen_kill_estimator);
  * @bstats: basic statistics
  * @cpu_bstats: bstats per cpu
  * @rate_est: rate estimator statistics
- * @stats_lock: statistics lock
+ * @lock: lock for statistics and control path
  * @running: qdisc running seqcount (might be NULL)
  * @opt: rate estimator configuration TLV
  *
@@ -221,11 +226,11 @@ EXPORT_SYMBOL(gen_kill_estimator);
 int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
 			  struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 			  struct net_rate_estimator __rcu **rate_est,
-			  spinlock_t *stats_lock,
+			  spinlock_t *lock,
 			  seqcount_t *running, struct nlattr *opt)
 {
 	return gen_new_estimator(bstats, cpu_bstats, rate_est,
-				 stats_lock, running, opt);
+				 lock, running, opt);
 }
 EXPORT_SYMBOL(gen_replace_estimator);
 
-- 
2.7.5