On Wed, 2 Oct 2019 11:20:52 +0300, same...@amazon.com wrote:
> From: Sameeh Jubran <same...@amazon.com>
>
> Set channels callback enables the user to change the count of queues
> used by the driver using ethtool. We decided to currently support only
> equal number of rx and tx queues, this might change in the future.
>
> Also rename dev_up to dev_was_up in ena_update_queue_count() to make
> it clearer.
>
> Signed-off-by: Sameeh Jubran <same...@amazon.com>
> ---
> drivers/net/ethernet/amazon/ena/ena_ethtool.c | 17 ++++++++++++++
> drivers/net/ethernet/amazon/ena/ena_netdev.c | 22 ++++++++++++++++---
> drivers/net/ethernet/amazon/ena/ena_netdev.h | 3 +++
> 3 files changed, 39 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/amazon/ena/ena_ethtool.c
> b/drivers/net/ethernet/amazon/ena/ena_ethtool.c
> index c9d760465..f58fc3c68 100644
> --- a/drivers/net/ethernet/amazon/ena/ena_ethtool.c
> +++ b/drivers/net/ethernet/amazon/ena/ena_ethtool.c
> @@ -744,6 +744,22 @@ static void ena_get_channels(struct net_device *netdev,
> channels->combined_count = 0;
> }
>
> +static int ena_set_channels(struct net_device *netdev,
> + struct ethtool_channels *channels)
> +{
> + struct ena_adapter *adapter = netdev_priv(netdev);
> + u32 new_channel_count;
> +
> + if (channels->rx_count != channels->tx_count ||
If you use the same IRQ and NAPI to service RX and TX it's a combined
channel, not rx and tx channels.
> + channels->max_tx != channels->max_rx)
Hm.. maxes are generally ignored on set 🤔
> + return -EINVAL;
> +
> + new_channel_count = clamp_val(channels->tx_count,
> + ENA_MIN_NUM_IO_QUEUES, channels->max_tx);
You should return an error if the value is not within bounds, rather
than guessing.
> + return ena_update_queue_count(adapter, new_channel_count);
> +}
> +
> static int ena_get_tunable(struct net_device *netdev,
> const struct ethtool_tunable *tuna, void *data)
> {
> @@ -807,6 +823,7 @@ static const struct ethtool_ops ena_ethtool_ops = {
> .get_rxfh = ena_get_rxfh,
> .set_rxfh = ena_set_rxfh,
> .get_channels = ena_get_channels,
> + .set_channels = ena_set_channels,
> .get_tunable = ena_get_tunable,
> .set_tunable = ena_set_tunable,
> };
> diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c
> b/drivers/net/ethernet/amazon/ena/ena_netdev.c
> index e964783c4..7d44b3440 100644
> --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
> +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
> @@ -2044,14 +2044,30 @@ int ena_update_queue_sizes(struct ena_adapter
> *adapter,
> u32 new_tx_size,
> u32 new_rx_size)
> {
> - bool dev_up;
> + bool dev_was_up;
>
> - dev_up = test_bit(ENA_FLAG_DEV_UP, &adapter->flags);
> + dev_was_up = test_bit(ENA_FLAG_DEV_UP, &adapter->flags);
> ena_close(adapter->netdev);
> adapter->requested_tx_ring_size = new_tx_size;
> adapter->requested_rx_ring_size = new_rx_size;
> ena_init_io_rings(adapter);
> - return dev_up ? ena_up(adapter) : 0;
> + return dev_was_up ? ena_up(adapter) : 0;
> +}
> +
> +int ena_update_queue_count(struct ena_adapter *adapter, u32
> new_channel_count)
> +{
> + struct ena_com_dev *ena_dev = adapter->ena_dev;
> + bool dev_was_up;
> +
> + dev_was_up = test_bit(ENA_FLAG_DEV_UP, &adapter->flags);
> + ena_close(adapter->netdev);
> + adapter->num_io_queues = new_channel_count;
> + /* We need to destroy the rss table so that the indirection
> + * table will be reinitialized by ena_up()
> + */
> + ena_com_rss_destroy(ena_dev);
> + ena_init_io_rings(adapter);
> + return dev_was_up ? ena_open(adapter->netdev) : 0;
You should try to prepare the resources for the new configuration
before you attempt the change. Otherwise if allocation of new rings
fails the open will leave the device in a broken state.
This is not always enforced upstream, but you can see mlx5 or nfp for
examples of drivers which do this right..
> }
>
> static void ena_tx_csum(struct ena_com_tx_ctx *ena_tx_ctx, struct sk_buff
> *skb)
