queue-4.20/mlxsw-__mlxsw_sp_port_headroom_set-fix-a-use-of-loca.patch

   1 From 2aad67f8d919f7e8f4284a78ad12741ac3377fd5 Mon Sep 17 00:00:00 2001
   2 From: Petr Machata <petrm@mellanox.com>
   3 Date: Sun, 17 Feb 2019 07:18:41 +0000
   4 Subject: mlxsw: __mlxsw_sp_port_headroom_set(): Fix a use of local variable
   5
   6 [ Upstream commit 289460404f6947ef1c38e67d680be9a84161250b ]
   7
   8 The function-local variable "delay" enters the loop interpreted as delay
   9 in bits. However, inside the loop it gets overwritten by the result of
  10 mlxsw_sp_pg_buf_delay_get(), and thus leaves the loop as quantity in
  11 cells. Thus on second and further loop iterations, the headroom for a
  12 given priority is configured with a wrong size.
  13
  14 Fix by introducing a loop-local variable, delay_cells. Rename thres to
  15 thres_cells for consistency.
  16
  17 Fixes: f417f04da589 ("mlxsw: spectrum: Refactor port buffer configuration")
  18 Signed-off-by: Petr Machata <petrm@mellanox.com>
  19 Acked-by: Jiri Pirko <jiri@mellanox.com>
  20 Signed-off-by: Ido Schimmel <idosch@mellanox.com>
  21 Signed-off-by: David S. Miller <davem@davemloft.net>
  22 Signed-off-by: Sasha Levin <sashal@kernel.org>
  23 ---
  24  drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 12 +++++++-----
  25  1 file changed, 7 insertions(+), 5 deletions(-)
  26
  27 diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
  28 index 8f1180fff9551..280173b489624 100644
  29 --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
  30 +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
  31 @@ -845,8 +845,9 @@ int __mlxsw_sp_port_headroom_set(struct mlxsw_sp_port *mlxsw_sp_port, int mtu,
  32         for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
  33                 bool configure = false;
  34                 bool pfc = false;
  35 +               u16 thres_cells;
  36 +               u16 delay_cells;
  37                 bool lossy;
  38 -               u16 thres;
  39
  40                 for (j = 0; j < IEEE_8021QAZ_MAX_TCS; j++) {
  41                         if (prio_tc[j] == i) {
  42 @@ -860,10 +861,11 @@ int __mlxsw_sp_port_headroom_set(struct mlxsw_sp_port *mlxsw_sp_port, int mtu,
  43                         continue;
  44
  45                 lossy = !(pfc || pause_en);
  46 -               thres = mlxsw_sp_pg_buf_threshold_get(mlxsw_sp, mtu);
  47 -               delay = mlxsw_sp_pg_buf_delay_get(mlxsw_sp, mtu, delay, pfc,
  48 -                                                 pause_en);
  49 -               mlxsw_sp_pg_buf_pack(pbmc_pl, i, thres + delay, thres, lossy);
  50 +               thres_cells = mlxsw_sp_pg_buf_threshold_get(mlxsw_sp, mtu);
  51 +               delay_cells = mlxsw_sp_pg_buf_delay_get(mlxsw_sp, mtu, delay,
  52 +                                                       pfc, pause_en);
  53 +               mlxsw_sp_pg_buf_pack(pbmc_pl, i, thres_cells + delay_cells,
  54 +                                    thres_cells, lossy);
  55         }
  56
  57         return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(pbmc), pbmc_pl);
  58 --
  59 2.19.1
  60