net: restore gnet_stats_basic to previous definition

In 5e140dfc1fe87eae27846f193086724806b33c7d "net: reorder struct Qdisc
for better SMP performance" the definition of struct gnet_stats_basic
changed incompatibly, as copies of this struct are shipped to
userland via netlink.

Restoring old behavior is not welcome, for performance reason.

Fix is to use a private structure for kernel, and
teach gnet_stats_copy_basic() to convert from kernel to user land,
using legacy structure (struct gnet_stats_basic)

Based on a report and initial patch from Michael Spang.

Reported-by: Michael Spang <mspang@csclub.uwaterloo.ca>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 5 deletions

diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
index d136b5240ef2..c1488553e349 100644
--- a/include/net/gen_stats.h
+++ b/include/net/gen_stats.h
@@ -28,7 +28,7 @@ extern int gnet_stats_start_copy_compat(struct sk_buff *skb, int type,
                                         spinlock_t *lock, struct gnet_dump *d);
 
 extern int gnet_stats_copy_basic(struct gnet_dump *d,
-                                 struct gnet_stats_basic *b);
+                                 struct gnet_stats_basic_packed *b);
 extern int gnet_stats_copy_rate_est(struct gnet_dump *d,
                                     struct gnet_stats_rate_est *r);
 extern int gnet_stats_copy_queue(struct gnet_dump *d,
@@ -37,14 +37,14 @@ extern int gnet_stats_copy_app(struct gnet_dump *d, void *st, int len);
 
 extern int gnet_stats_finish_copy(struct gnet_dump *d);
 
-extern int gen_new_estimator(struct gnet_stats_basic *bstats,
+extern int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
                              struct gnet_stats_rate_est *rate_est,
                              spinlock_t *stats_lock, struct nlattr *opt);
-extern void gen_kill_estimator(struct gnet_stats_basic *bstats,
+extern void gen_kill_estimator(struct gnet_stats_basic_packed *bstats,
                                struct gnet_stats_rate_est *rate_est);
-extern int gen_replace_estimator(struct gnet_stats_basic *bstats,
+extern int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
                                  struct gnet_stats_rate_est *rate_est,
                                  spinlock_t *stats_lock, struct nlattr *opt);
-extern bool gen_estimator_active(const struct gnet_stats_basic *bstats,
+extern bool gen_estimator_active(const struct gnet_stats_basic_packed *bstats,
                                  const struct gnet_stats_rate_est *rate_est);
 #endif