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>
diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c
index 2a8b83a..ab82f14 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -49,7 +49,7 @@
 	struct socket		*sock;		/* for closing */
 	u32			classid;	/* x:y type ID */
 	int			ref;		/* reference count */
-	struct gnet_stats_basic	bstats;
+	struct gnet_stats_basic_packed	bstats;
 	struct gnet_stats_queue	qstats;
 	struct atm_flow_data	*next;
 	struct atm_flow_data	*excess;	/* flow for excess traffic;
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 23a1676..d5798e1 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -128,7 +128,7 @@
 	long			avgidle;
 	long			deficit;	/* Saved deficit for WRR */
 	psched_time_t		penalized;
-	struct gnet_stats_basic bstats;
+	struct gnet_stats_basic_packed bstats;
 	struct gnet_stats_queue qstats;
 	struct gnet_stats_rate_est rate_est;
 	struct tc_cbq_xstats	xstats;
diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c
index 7597fe1..12b2fb04 100644
--- a/net/sched/sch_drr.c
+++ b/net/sched/sch_drr.c
@@ -22,7 +22,7 @@
 	unsigned int			refcnt;
 	unsigned int			filter_cnt;
 
-	struct gnet_stats_basic		bstats;
+	struct gnet_stats_basic_packed		bstats;
 	struct gnet_stats_queue		qstats;
 	struct gnet_stats_rate_est	rate_est;
 	struct list_head		alist;
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 362c281..dad0144 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -116,7 +116,7 @@
 	struct Qdisc_class_common cl_common;
 	unsigned int	refcnt;		/* usage count */
 
-	struct gnet_stats_basic bstats;
+	struct gnet_stats_basic_packed bstats;
 	struct gnet_stats_queue qstats;
 	struct gnet_stats_rate_est rate_est;
 	unsigned int	level;		/* class level in hierarchy */
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 88cd026..ec4d463 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -74,7 +74,7 @@
 struct htb_class {
 	struct Qdisc_class_common common;
 	/* general class parameters */
-	struct gnet_stats_basic bstats;
+	struct gnet_stats_basic_packed bstats;
 	struct gnet_stats_queue qstats;
 	struct gnet_stats_rate_est rate_est;
 	struct tc_htb_xstats xstats;	/* our special stats */