target/linux/generic/backport-4.19/397-5.8-sch_cake-don-t-call-diffserv-parsing-code-when-it-is.patch

   1 From 8c95eca0bb8c4bd2231a0d581f1ad0d50c90488c Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
   3 Date: Thu, 25 Jun 2020 22:12:08 +0200
   4 Subject: [PATCH] sch_cake: don't call diffserv parsing code when it is not
   5  needed
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 As a further optimisation of the diffserv parsing codepath, we can skip it
  11 entirely if CAKE is configured to neither use diffserv-based
  12 classification, nor to zero out the diffserv bits.
  13
  14 Fixes: c87b4ecdbe8d ("sch_cake: Make sure we can write the IP header before changing DSCP bits")
  15 Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
  16 Signed-off-by: David S. Miller <davem@davemloft.net>
  17 Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
  18 ---
  19  net/sched/sch_cake.c | 13 +++++++++----
  20  1 file changed, 9 insertions(+), 4 deletions(-)
  21
  22 --- a/net/sched/sch_cake.c
  23 +++ b/net/sched/sch_cake.c
  24 @@ -1551,7 +1551,7 @@ static unsigned int cake_drop(struct Qdi
  25         return idx + (tin << 16);
  26  }
  27
  28 -static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)
  29 +static u8 cake_handle_diffserv(struct sk_buff *skb, bool wash)
  30  {
  31         const int offset = skb_network_offset(skb);
  32         u16 *buf, buf_;
  33 @@ -1612,14 +1612,17 @@ static struct cake_tin_data *cake_select
  34  {
  35         struct cake_sched_data *q = qdisc_priv(sch);
  36         u32 tin, mark;
  37 +       bool wash;
  38         u8 dscp;
  39
  40         /* Tin selection: Default to diffserv-based selection, allow overriding
  41 -        * using firewall marks or skb->priority.
  42 +        * using firewall marks or skb->priority. Call DSCP parsing early if
  43 +        * wash is enabled, otherwise defer to below to skip unneeded parsing.
  44          */
  45 -       dscp = cake_handle_diffserv(skb,
  46 -                                   q->rate_flags & CAKE_FLAG_WASH);
  47         mark = (skb->mark & q->fwmark_mask) >> q->fwmark_shft;
  48 +       wash = !!(q->rate_flags & CAKE_FLAG_WASH);
  49 +       if (wash)
  50 +               dscp = cake_handle_diffserv(skb, wash);
  51
  52         if (q->tin_mode == CAKE_DIFFSERV_BESTEFFORT)
  53                 tin = 0;
  54 @@ -1630,6 +1633,8 @@ static struct cake_tin_data *cake_select
  55                 tin = q->tin_order[TC_H_MIN(skb->priority) - 1];
  56
  57         else {
  58 +               if (!wash)
  59 +                       dscp = cake_handle_diffserv(skb, wash);
  60                 tin = q->tin_index[dscp];
  61
  62                 if (unlikely(tin >= q->tin_cnt))