net: sched: restrict use of qstats qlen

This removes the use of qstats->qlen variable from the classifiers
and makes it an explicit argument to gnet_stats_copy_queue().

The qlen represents the qdisc queue length and is packed into
the qstats at the last moment before passnig to user space. By
handling it explicitely we avoid, in the percpu stats case, having
to figure out which per_cpu variable to put it in.

It would probably be best to remove it from qstats completely
but qstats is a user space ABI and can't be broken. A future
patch could make an internal only qstats structure that would
avoid having to allocate an additional u32 variable on the
Qdisc struct. This would make the qstats struct 128bits instead
of 128+32.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c
index 5ff8e80fe0bb..ad3ecb6ba835 100644
--- a/net/core/gen_stats.c
+++ b/net/core/gen_stats.c
@@ -219,6 +219,7 @@ EXPORT_SYMBOL(gnet_stats_copy_rate_est);
  * gnet_stats_copy_queue - copy queue statistics into statistics TLV
  * @d: dumping handle
  * @q: queue statistics
+ * @qlen: queue length statistics
  *
  * Appends the queue statistics to the top level TLV created by
  * gnet_stats_start_copy().
@@ -227,8 +228,11 @@ EXPORT_SYMBOL(gnet_stats_copy_rate_est);
  * if the room in the socket buffer was not sufficient.
  */
 int
-gnet_stats_copy_queue(struct gnet_dump *d, struct gnet_stats_queue *q)
+gnet_stats_copy_queue(struct gnet_dump *d,
+                      struct gnet_stats_queue *q, __u32 qlen)
 {
+        q->qlen = qlen;
+
         if (d->compat_tc_stats) {
                 d->tc_stats.drops = q->drops;
                 d->tc_stats.qlen = q->qlen;