A bug occurs because a safety check guarding AF_XDP-related queues in
ethnl_set_channels(), does not trigger. This happens, because kernel and
ice driver interpret the ethtool command differently.
How the bug occurs:
1. ethtool -l <IFNAME> -> combined: 40
2. Attach AF_XDP to queue 30
3. ethtool -L <IFNAME> rx 15 tx 15
combined number is not specified, so command becomes {rx_count = 15,
tx_count = 15, combined_count = 40}.
4. ethnl_set_channels checks, if there are any AF_XDP of queues from the
new (combined_count + rx_count) to the old one, so from 55 to 40, check
does not trigger.
5. ice interprets `rx 15 tx 15` as 15 combined channels and deletes the
queue that AF_XDP is attached to.
Interpret the command in a way that is more consistent with ethtool
manual [0] (--show-channels and --set-channels).
Considering that in the ice driver only the difference between RX and TX
queues forms dedicated channels, change the correct way to set number of
channels to:
ethtool -L <IFNAME> combined 10 /* For symmetric queues */
ethtool -L <IFNAME> combined 8 tx 2 rx 0 /* For asymmetric queues */
[0] https://man7.org/linux/man-pages/man8/ethtool.8.html
Fixes: 87324e747fde ("ice: Implement ethtool ops for channels")
Reviewed-by: Michal Swiatkowski <[email protected]>
Signed-off-by: Larysa Zaremba <[email protected]>
---
drivers/net/ethernet/intel/ice/ice_ethtool.c | 22 ++++++--------------
1 file changed, 6 insertions(+), 16 deletions(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c
b/drivers/net/ethernet/intel/ice/ice_ethtool.c
index 78b833b3e1d7..d91f41f61bce 100644
--- a/drivers/net/ethernet/intel/ice/ice_ethtool.c
+++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
@@ -3593,7 +3593,6 @@ static int ice_set_channels(struct net_device *dev,
struct ethtool_channels *ch)
struct ice_pf *pf = vsi->back;
int new_rx = 0, new_tx = 0;
bool locked = false;
- u32 curr_combined;
int ret = 0;
/* do not support changing channels in Safe Mode */
@@ -3615,22 +3614,13 @@ static int ice_set_channels(struct net_device *dev,
struct ethtool_channels *ch)
return -EOPNOTSUPP;
}
- curr_combined = ice_get_combined_cnt(vsi);
+ if (!ch->combined_count) {
+ netdev_err(dev, "Please specify at least 1 combined channel\n");
+ return -EINVAL;
+ }
- /* these checks are for cases where user didn't specify a particular
- * value on cmd line but we get non-zero value anyway via
- * get_channels(); look at ethtool.c in ethtool repository (the user
- * space part), particularly, do_schannels() routine
- */
- if (ch->rx_count == vsi->num_rxq - curr_combined)
- ch->rx_count = 0;
- if (ch->tx_count == vsi->num_txq - curr_combined)
- ch->tx_count = 0;
- if (ch->combined_count == curr_combined)
- ch->combined_count = 0;
-
- if (!(ch->combined_count || (ch->rx_count && ch->tx_count))) {
- netdev_err(dev, "Please specify at least 1 Rx and 1 Tx
channel\n");
+ if (ch->rx_count && ch->tx_count) {
+ netdev_err(dev, "Dedicated RX or TX channels cannot be used
simultaneously\n");
return -EINVAL;
}
--
2.43.0
