net: sched: Merge Qdisc::bstats and Qdisc::cpu_bstats data types

The only factor differentiating per-CPU bstats data type (struct
gnet_stats_basic_cpu) from the packed non-per-CPU one (struct
gnet_stats_basic_packed) was a u64_stats sync point inside the former.
The two data types are now equivalent: earlier commits added a u64_stats
sync point to the latter.

Combine both data types into "struct gnet_stats_basic_sync". This
eliminates redundancy and simplifies the bstats read/write APIs.

Use u64_stats_t for bstats "packets" and "bytes" data types. On 64-bit
architectures, u64_stats sync points do not use sequence counter
protection.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 21 deletions

diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
index 304d792f7977..52b87588f467 100644
--- a/include/net/gen_stats.h
+++ b/include/net/gen_stats.h
@@ -7,15 +7,17 @@
 #include <linux/rtnetlink.h>
 #include <linux/pkt_sched.h>
 
-/* Note: this used to be in include/uapi/linux/gen_stats.h */
-struct gnet_stats_basic_packed {
-	__u64	bytes;
-	__u64	packets;
-	struct u64_stats_sync syncp;
-};
-
-struct gnet_stats_basic_cpu {
-	struct gnet_stats_basic_packed bstats;
+/* Throughput stats.
+ * Must be initialized beforehand with gnet_stats_basic_sync_init().
+ *
+ * If no reads can ever occur parallel to writes (e.g. stack-allocated
+ * bstats), then the internal stat values can be written to and read
+ * from directly. Otherwise, use _bstats_set/update() for writes and
+ * gnet_stats_add_basic() for reads.
+ */
+struct gnet_stats_basic_sync {
+	u64_stats_t bytes;
+	u64_stats_t packets;
 	struct u64_stats_sync syncp;
 } __aligned(2 * sizeof(u64));
 
@@ -35,7 +37,7 @@ struct gnet_dump {
 	struct tc_stats   tc_stats;
 };
 
-void gnet_stats_basic_packed_init(struct gnet_stats_basic_packed *b);
+void gnet_stats_basic_sync_init(struct gnet_stats_basic_sync *b);
 int gnet_stats_start_copy(struct sk_buff *skb, int type, spinlock_t *lock,
 			  struct gnet_dump *d, int padattr);
 
@@ -46,16 +48,16 @@ int gnet_stats_start_copy_compat(struct sk_buff *skb, int type,
 
 int gnet_stats_copy_basic(const seqcount_t *running,
 			  struct gnet_dump *d,
-			  struct gnet_stats_basic_cpu __percpu *cpu,
-			  struct gnet_stats_basic_packed *b);
+			  struct gnet_stats_basic_sync __percpu *cpu,
+			  struct gnet_stats_basic_sync *b);
 void gnet_stats_add_basic(const seqcount_t *running,
-			  struct gnet_stats_basic_packed *bstats,
-			  struct gnet_stats_basic_cpu __percpu *cpu,
-			  struct gnet_stats_basic_packed *b);
+			  struct gnet_stats_basic_sync *bstats,
+			  struct gnet_stats_basic_sync __percpu *cpu,
+			  struct gnet_stats_basic_sync *b);
 int gnet_stats_copy_basic_hw(const seqcount_t *running,
 			     struct gnet_dump *d,
-			     struct gnet_stats_basic_cpu __percpu *cpu,
-			     struct gnet_stats_basic_packed *b);
+			     struct gnet_stats_basic_sync __percpu *cpu,
+			     struct gnet_stats_basic_sync *b);
 int gnet_stats_copy_rate_est(struct gnet_dump *d,
 			     struct net_rate_estimator __rcu **ptr);
 int gnet_stats_copy_queue(struct gnet_dump *d,
@@ -68,14 +70,14 @@ int gnet_stats_copy_app(struct gnet_dump *d, void *st, int len);
 
 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,
+int gen_new_estimator(struct gnet_stats_basic_sync *bstats,
+		      struct gnet_stats_basic_sync __percpu *cpu_bstats,
 		      struct net_rate_estimator __rcu **rate_est,
 		      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,
+int gen_replace_estimator(struct gnet_stats_basic_sync *bstats,
+			  struct gnet_stats_basic_sync __percpu *cpu_bstats,
 			  struct net_rate_estimator __rcu **ptr,
 			  spinlock_t *lock,
 			  seqcount_t *running, struct nlattr *opt);