i40e: prevent changing ITR if adaptive-rx/tx enabled

Currently the driver allows the user to change (or even disable)
interrupt moderation if adaptive-rx/tx is enabled when this should
not be the case.

Adaptive RX/TX will not respect the user's ITR settings so
allowing the user to change it is weird.  This bug would also
allow the user to disable interrupt moderation with adaptive-rx/tx
enabled which doesn't make much sense either.

This patch makes it such that if adaptive-rx/tx is enabled, the user
cannot make any manual adjustments to interrupt moderation.  It also
makes it so that if ITR is disabled but adaptive-rx/tx is then
enabled, ITR will be re-enabled.

Signed-off-by: Alan Brady <alan.brady@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
index a868c8d4fec97c3afb68262e0433e819b3816f66..05e89864f781c361289f0a3170078a661988389b 100644 (file)
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -2194,14 +2194,29 @@ static int __i40e_set_coalesce(struct net_device *netdev,
                               int queue)
 {
        struct i40e_netdev_priv *np = netdev_priv(netdev);
+       u16 intrl_reg, cur_rx_itr, cur_tx_itr;
        struct i40e_vsi *vsi = np->vsi;
        struct i40e_pf *pf = vsi->back;
-       u16 intrl_reg;
        int i;
 
        if (ec->tx_max_coalesced_frames_irq || ec->rx_max_coalesced_frames_irq)
                vsi->work_limit = ec->tx_max_coalesced_frames_irq;
 
+       if (queue < 0) {
+               cur_rx_itr = vsi->rx_rings[0]->rx_itr_setting;
+               cur_tx_itr = vsi->tx_rings[0]->tx_itr_setting;
+       } else if (queue < vsi->num_queue_pairs) {
+               cur_rx_itr = vsi->rx_rings[queue]->rx_itr_setting;
+               cur_tx_itr = vsi->tx_rings[queue]->tx_itr_setting;
+       } else {
+               netif_info(pf, drv, netdev, "Invalid queue value, queue range is 0 - %d\n",
+                          vsi->num_queue_pairs - 1);
+               return -EINVAL;
+       }
+
+       cur_tx_itr &= ~I40E_ITR_DYNAMIC;
+       cur_rx_itr &= ~I40E_ITR_DYNAMIC;
+
        /* tx_coalesce_usecs_high is ignored, use rx-usecs-high instead */
        if (ec->tx_coalesce_usecs_high != vsi->int_rate_limit) {
                netif_info(pf, drv, netdev, "tx-usecs-high is not used, please program rx-usecs-high\n");
@@ -2214,15 +2229,34 @@ static int __i40e_set_coalesce(struct net_device *netdev,
                return -EINVAL;
        }
 
-       if (ec->rx_coalesce_usecs == 0) {
-               if (ec->use_adaptive_rx_coalesce)
-                       netif_info(pf, drv, netdev, "rx-usecs=0, need to disable adaptive-rx for a complete disable\n");
-       } else if ((ec->rx_coalesce_usecs < (I40E_MIN_ITR << 1)) ||
-                  (ec->rx_coalesce_usecs > (I40E_MAX_ITR << 1))) {
-                       netif_info(pf, drv, netdev, "Invalid value, rx-usecs range is 0-8160\n");
-                       return -EINVAL;
+       if (ec->rx_coalesce_usecs != cur_rx_itr &&
+           ec->use_adaptive_rx_coalesce) {
+               netif_info(pf, drv, netdev, "RX interrupt moderation cannot be changed if adaptive-rx is enabled.\n");
+               return -EINVAL;
+       }
+
+       if (ec->rx_coalesce_usecs > (I40E_MAX_ITR << 1)) {
+               netif_info(pf, drv, netdev, "Invalid value, rx-usecs range is 0-8160\n");
+               return -EINVAL;
        }
 
+       if (ec->tx_coalesce_usecs != cur_tx_itr &&
+           ec->use_adaptive_tx_coalesce) {
+               netif_info(pf, drv, netdev, "TX interrupt moderation cannot be changed if adaptive-tx is enabled.\n");
+               return -EINVAL;
+       }
+
+       if (ec->tx_coalesce_usecs > (I40E_MAX_ITR << 1)) {
+               netif_info(pf, drv, netdev, "Invalid value, tx-usecs range is 0-8160\n");
+               return -EINVAL;
+       }
+
+       if (ec->use_adaptive_rx_coalesce && !cur_rx_itr)
+               ec->rx_coalesce_usecs = I40E_MIN_ITR << 1;
+
+       if (ec->use_adaptive_tx_coalesce && !cur_tx_itr)
+               ec->tx_coalesce_usecs = I40E_MIN_ITR << 1;
+
        intrl_reg = i40e_intrl_usec_to_reg(ec->rx_coalesce_usecs_high);
        vsi->int_rate_limit = INTRL_REG_TO_USEC(intrl_reg);
        if (vsi->int_rate_limit != ec->rx_coalesce_usecs_high) {
@@ -2230,27 +2264,14 @@ static int __i40e_set_coalesce(struct net_device *netdev,
                           vsi->int_rate_limit);
        }
 
-       if (ec->tx_coalesce_usecs == 0) {
-               if (ec->use_adaptive_tx_coalesce)
-                       netif_info(pf, drv, netdev, "tx-usecs=0, need to disable adaptive-tx for a complete disable\n");
-       } else if ((ec->tx_coalesce_usecs < (I40E_MIN_ITR << 1)) ||
-                  (ec->tx_coalesce_usecs > (I40E_MAX_ITR << 1))) {
-                       netif_info(pf, drv, netdev, "Invalid value, tx-usecs range is 0-8160\n");
-                       return -EINVAL;
-       }
-
        /* rx and tx usecs has per queue value. If user doesn't specify the queue,
         * apply to all queues.
         */
        if (queue < 0) {
                for (i = 0; i < vsi->num_queue_pairs; i++)
                        i40e_set_itr_per_queue(vsi, ec, i);
-       } else if (queue < vsi->num_queue_pairs) {
-               i40e_set_itr_per_queue(vsi, ec, queue);
        } else {
-               netif_info(pf, drv, netdev, "Invalid queue value, queue range is 0 - %d\n",
-                          vsi->num_queue_pairs - 1);
-               return -EINVAL;
+               i40e_set_itr_per_queue(vsi, ec, queue);
        }
 
        return 0;