From: Wei Fang wei.fang@nxp.com
[ Upstream commit 21225873be1472b7c59ed3650396af0e40578112 ]
For ENETC hardware, the TCs are numbered from 0 to N-1, where N is the number of TCs. Numerically higher TC has higher priority. It's obvious that the highest priority TC index should be N-1 and the 2nd highest priority TC index should be N-2.
However, the previous logic uses netdev_get_prio_tc_map() to get the indexes of highest priority and 2nd highest priority TCs, it does not make sense and is incorrect to give a "tc" argument to netdev_get_prio_tc_map(). So the driver may get the wrong indexes of the two highest priotiry TCs which would lead to failed to set the CBS for the two highest priotiry TCs.
e.g. $ tc qdisc add dev eno0 parent root handle 100: mqprio num_tc 6 \ map 0 0 1 1 2 3 4 5 queues 1@0 1@1 1@2 1@3 2@4 2@6 hw 1 $ tc qdisc replace dev eno0 parent 100:6 cbs idleslope 100000 \ sendslope -900000 hicredit 12 locredit -113 offload 1 $ Error: Specified device failed to setup cbs hardware offload. ^^^^^
In this example, the previous logic deems the indexes of the two highest priotiry TCs should be 3 and 2. Actually, the indexes are 5 and 4, because the number of TCs is 6. So it would be failed to configure the CBS for the two highest priority TCs.
Fixes: c431047c4efe ("enetc: add support Credit Based Shaper(CBS) for hardware offload") Signed-off-by: Wei Fang wei.fang@nxp.com Reviewed-by: Vladimir Oltean vladimir.oltean@nxp.com Reviewed-by: Maciej Fijalkowski maciej.fijalkowski@intel.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/freescale/enetc/enetc_qos.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_qos.c b/drivers/net/ethernet/freescale/enetc/enetc_qos.c index a8539a8554a13..762849959cc1b 100644 --- a/drivers/net/ethernet/freescale/enetc/enetc_qos.c +++ b/drivers/net/ethernet/freescale/enetc/enetc_qos.c @@ -189,8 +189,8 @@ int enetc_setup_tc_cbs(struct net_device *ndev, void *type_data) int bw_sum = 0; u8 bw;
- prio_top = netdev_get_prio_tc_map(ndev, tc_nums - 1); - prio_next = netdev_get_prio_tc_map(ndev, tc_nums - 2); + prio_top = tc_nums - 1; + prio_next = tc_nums - 2;
/* Support highest prio and second prio tc in cbs mode */ if (tc != prio_top && tc != prio_next)