sfc: Distinguish queue lookup from test for queue existence

efx_channel_get_{rx,tx}_queue() currently return NULL if the channel
isn't used for traffic in that direction.  In most cases this is a
bug, but some callers rely on it as an existence test.

Add existence test functions efx_channel_has_{rx_queue,tx_queues}()
and use them as appropriate.

Change efx_channel_get_{rx,tx}_queue() to assert that the requested
queue exists.

Remove now-redundant initialisation from efx_set_channels().

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/net/sfc/ethtool.c b/drivers/net/sfc/ethtool.c
index 713969accdb..272cfe724e1 100644
--- a/drivers/net/sfc/ethtool.c
+++ b/drivers/net/sfc/ethtool.c
@@ -631,7 +631,7 @@ static int efx_ethtool_get_coalesce(struct net_device *net_dev,
         /* Find lowest IRQ moderation across all used TX queues */
         coalesce->tx_coalesce_usecs_irq = ~((u32) 0);
         efx_for_each_channel(channel, efx) {
-                if (!efx_channel_get_tx_queue(channel, 0))
+                if (!efx_channel_has_tx_queues(channel))
                         continue;
                 if (channel->irq_moderation < coalesce->tx_coalesce_usecs_irq) {
                         if (channel->channel < efx->n_rx_channels)
@@ -676,8 +676,8 @@ static int efx_ethtool_set_coalesce(struct net_device *net_dev,
 
         /* If the channel is shared only allow RX parameters to be set */
         efx_for_each_channel(channel, efx) {
-                if (efx_channel_get_rx_queue(channel) &&
-                    efx_channel_get_tx_queue(channel, 0) &&
+                if (efx_channel_has_rx_queue(channel) &&
+                    efx_channel_has_tx_queues(channel) &&
                     tx_usecs) {
                         netif_err(efx, drv, efx->net_dev, "Channel is shared. "
                                   "Only RX coalescing may be set\n");