sfc: Create multiple TX queues

Create a core TX queue and 2 hardware TX queues for each channel.
If separate_tx_channels is set, create equal numbers of RX and TX
channels instead.

Rewrite the channel and queue iteration macros accordingly.
Eliminate efx_channel::used_flags as redundant.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 61 insertions, 52 deletions

diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index 5e3f944fdd95..bc75ef683c9f 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -288,7 +288,7 @@ static int efx_poll(struct napi_struct *napi, int budget)
         if (spent < budget) {
                 struct efx_nic *efx = channel->efx;
 
-                if (channel->used_flags & EFX_USED_BY_RX &&
+                if (channel->channel < efx->n_rx_channels &&
                     efx->irq_rx_adaptive &&
                     unlikely(++channel->irq_count == 1000)) {
                         if (unlikely(channel->irq_mod_score <
@@ -333,7 +333,6 @@ void efx_process_channel_now(struct efx_channel *channel)
 {
         struct efx_nic *efx = channel->efx;
 
-        BUG_ON(!channel->used_flags);
         BUG_ON(!channel->enabled);
 
         /* Disable interrupts and wait for ISRs to complete */
@@ -446,12 +445,12 @@ static void efx_set_channel_names(struct efx_nic *efx)
 
         efx_for_each_channel(channel, efx) {
                 number = channel->channel;
-                if (efx->n_channels > efx->n_rx_queues) {
-                        if (channel->channel < efx->n_rx_queues) {
+                if (efx->n_channels > efx->n_rx_channels) {
+                        if (channel->channel < efx->n_rx_channels) {
                                 type = "-rx";
                         } else {
                                 type = "-tx";
-                                number -= efx->n_rx_queues;
+                                number -= efx->n_rx_channels;
                         }
                 }
                 snprintf(channel->name, sizeof(channel->name),
@@ -585,8 +584,6 @@ static void efx_remove_channel(struct efx_channel *channel)
         efx_for_each_channel_tx_queue(tx_queue, channel)
                 efx_remove_tx_queue(tx_queue);
         efx_remove_eventq(channel);
-
-        channel->used_flags = 0;
 }
 
 void efx_schedule_slow_fill(struct efx_rx_queue *rx_queue, int delay)
@@ -956,10 +953,9 @@ static void efx_fini_io(struct efx_nic *efx)
         pci_disable_device(efx->pci_dev);
 }
 
-/* Get number of RX queues wanted.  Return number of online CPU
- * packages in the expectation that an IRQ balancer will spread
- * interrupts across them. */
-static int efx_wanted_rx_queues(void)
+/* Get number of channels wanted.  Each channel will have its own IRQ,
+ * 1 RX queue and/or 2 TX queues. */
+static int efx_wanted_channels(void)
 {
         cpumask_var_t core_mask;
         int count;
@@ -995,34 +991,39 @@ static void efx_probe_interrupts(struct efx_nic *efx)
 
         if (efx->interrupt_mode == EFX_INT_MODE_MSIX) {
                 struct msix_entry xentries[EFX_MAX_CHANNELS];
-                int wanted_ints;
-                int rx_queues;
+                int n_channels;
 
-                /* We want one RX queue and interrupt per CPU package
-                 * (or as specified by the rss_cpus module parameter).
-                 * We will need one channel per interrupt.
-                 */
-                rx_queues = rss_cpus ? rss_cpus : efx_wanted_rx_queues();
-                wanted_ints = rx_queues + (separate_tx_channels ? 1 : 0);
-                wanted_ints = min(wanted_ints, max_channels);
+                n_channels = efx_wanted_channels();
+                if (separate_tx_channels)
+                        n_channels *= 2;
+                n_channels = min(n_channels, max_channels);
 
-                for (i = 0; i < wanted_ints; i++)
+                for (i = 0; i < n_channels; i++)
                         xentries[i].entry = i;
-                rc = pci_enable_msix(efx->pci_dev, xentries, wanted_ints);
+                rc = pci_enable_msix(efx->pci_dev, xentries, n_channels);
                 if (rc > 0) {
                         EFX_ERR(efx, "WARNING: Insufficient MSI-X vectors"
-                                " available (%d < %d).\n", rc, wanted_ints);
+                                " available (%d < %d).\n", rc, n_channels);
                         EFX_ERR(efx, "WARNING: Performance may be reduced.\n");
-                        EFX_BUG_ON_PARANOID(rc >= wanted_ints);
-                        wanted_ints = rc;
+                        EFX_BUG_ON_PARANOID(rc >= n_channels);
+                        n_channels = rc;
                         rc = pci_enable_msix(efx->pci_dev, xentries,
-                                             wanted_ints);
+                                             n_channels);
                 }
 
                 if (rc == 0) {
-                        efx->n_rx_queues = min(rx_queues, wanted_ints);
-                        efx->n_channels = wanted_ints;
-                        for (i = 0; i < wanted_ints; i++)
+                        efx->n_channels = n_channels;
+                        if (separate_tx_channels) {
+                                efx->n_tx_channels =
+                                        max(efx->n_channels / 2, 1U);
+                                efx->n_rx_channels =
+                                        max(efx->n_channels -
+                                            efx->n_tx_channels, 1U);
+                        } else {
+                                efx->n_tx_channels = efx->n_channels;
+                                efx->n_rx_channels = efx->n_channels;
+                        }
+                        for (i = 0; i < n_channels; i++)
                                 efx->channel[i].irq = xentries[i].vector;
                 } else {
                         /* Fall back to single channel MSI */
@@ -1033,8 +1034,9 @@ static void efx_probe_interrupts(struct efx_nic *efx)
 
         /* Try single interrupt MSI */
         if (efx->interrupt_mode == EFX_INT_MODE_MSI) {
-                efx->n_rx_queues = 1;
                 efx->n_channels = 1;
+                efx->n_rx_channels = 1;
+                efx->n_tx_channels = 1;
                 rc = pci_enable_msi(efx->pci_dev);
                 if (rc == 0) {
                         efx->channel[0].irq = efx->pci_dev->irq;
@@ -1046,8 +1048,9 @@ static void efx_probe_interrupts(struct efx_nic *efx)
 
         /* Assume legacy interrupts */
         if (efx->interrupt_mode == EFX_INT_MODE_LEGACY) {
-                efx->n_rx_queues = 1;
                 efx->n_channels = 1 + (separate_tx_channels ? 1 : 0);
+                efx->n_rx_channels = 1;
+                efx->n_tx_channels = 1;
                 efx->legacy_irq = efx->pci_dev->irq;
         }
 }
@@ -1068,21 +1071,24 @@ static void efx_remove_interrupts(struct efx_nic *efx)
 
 static void efx_set_channels(struct efx_nic *efx)
 {
+        struct efx_channel *channel;
         struct efx_tx_queue *tx_queue;
         struct efx_rx_queue *rx_queue;
+        unsigned tx_channel_offset =
+                separate_tx_channels ? efx->n_channels - efx->n_tx_channels : 0;
 
-        efx_for_each_tx_queue(tx_queue, efx) {
-                if (separate_tx_channels)
-                        tx_queue->channel = &efx->channel[efx->n_channels-1];
-                else
-                        tx_queue->channel = &efx->channel[0];
-                tx_queue->channel->used_flags |= EFX_USED_BY_TX;
+        efx_for_each_channel(channel, efx) {
+                if (channel->channel - tx_channel_offset < efx->n_tx_channels) {
+                        channel->tx_queue = &efx->tx_queue[
+                                (channel->channel - tx_channel_offset) *
+                                EFX_TXQ_TYPES];
+                        efx_for_each_channel_tx_queue(tx_queue, channel)
+                                tx_queue->channel = channel;
+                }
         }
 
-        efx_for_each_rx_queue(rx_queue, efx) {
+        efx_for_each_rx_queue(rx_queue, efx)
                 rx_queue->channel = &efx->channel[rx_queue->queue];
-                rx_queue->channel->used_flags |= EFX_USED_BY_RX;
-        }
 }
 
 static int efx_probe_nic(struct efx_nic *efx)
@@ -1096,11 +1102,12 @@ static int efx_probe_nic(struct efx_nic *efx)
         if (rc)
                 return rc;
 
-        /* Determine the number of channels and RX queues by trying to hook
+        /* Determine the number of channels and queues by trying to hook
          * in MSI-X interrupts. */
         efx_probe_interrupts(efx);
 
         efx_set_channels(efx);
+        efx->net_dev->real_num_tx_queues = efx->n_tx_channels;
 
         /* Initialise the interrupt moderation settings */
         efx_init_irq_moderation(efx, tx_irq_mod_usec, rx_irq_mod_usec, true);
@@ -1187,11 +1194,12 @@ static void efx_start_all(struct efx_nic *efx)
         /* Mark the port as enabled so port reconfigurations can start, then
          * restart the transmit interface early so the watchdog timer stops */
         efx_start_port(efx);
-        if (efx_dev_registered(efx))
-                efx_wake_queue(efx);
 
-        efx_for_each_channel(channel, efx)
+        efx_for_each_channel(channel, efx) {
+                if (efx_dev_registered(efx))
+                        efx_wake_queue(channel);
                 efx_start_channel(channel);
+        }
 
         efx_nic_enable_interrupts(efx);
 
@@ -1282,7 +1290,9 @@ static void efx_stop_all(struct efx_nic *efx)
         /* Stop the kernel transmit interface late, so the watchdog
          * timer isn't ticking over the flush */
         if (efx_dev_registered(efx)) {
-                efx_stop_queue(efx);
+                struct efx_channel *channel;
+                efx_for_each_channel(channel, efx)
+                        efx_stop_queue(channel);
                 netif_tx_lock_bh(efx->net_dev);
                 netif_tx_unlock_bh(efx->net_dev);
         }
@@ -1537,9 +1547,8 @@ static void efx_watchdog(struct net_device *net_dev)
 {
         struct efx_nic *efx = netdev_priv(net_dev);
 
-        EFX_ERR(efx, "TX stuck with stop_count=%d port_enabled=%d:"
-                " resetting channels\n",
-                atomic_read(&efx->netif_stop_count), efx->port_enabled);
+        EFX_ERR(efx, "TX stuck with port_enabled=%d: resetting channels\n",
+                efx->port_enabled);
 
         efx_schedule_reset(efx, RESET_TYPE_TX_WATCHDOG);
 }
@@ -2014,22 +2023,22 @@ static int efx_init_struct(struct efx_nic *efx, struct efx_nic_type *type,
 
         efx->net_dev = net_dev;
         efx->rx_checksum_enabled = true;
-        spin_lock_init(&efx->netif_stop_lock);
         spin_lock_init(&efx->stats_lock);
         mutex_init(&efx->mac_lock);
         efx->mac_op = type->default_mac_ops;
         efx->phy_op = &efx_dummy_phy_operations;
         efx->mdio.dev = net_dev;
         INIT_WORK(&efx->mac_work, efx_mac_work);
-        atomic_set(&efx->netif_stop_count, 1);
 
         for (i = 0; i < EFX_MAX_CHANNELS; i++) {
                 channel = &efx->channel[i];
                 channel->efx = efx;
                 channel->channel = i;
                 channel->work_pending = false;
+                spin_lock_init(&channel->tx_stop_lock);
+                atomic_set(&channel->tx_stop_count, 1);
         }
-        for (i = 0; i < EFX_TX_QUEUE_COUNT; i++) {
+        for (i = 0; i < EFX_MAX_TX_QUEUES; i++) {
                 tx_queue = &efx->tx_queue[i];
                 tx_queue->efx = efx;
                 tx_queue->queue = i;
@@ -2201,7 +2210,7 @@ static int __devinit efx_pci_probe(struct pci_dev *pci_dev,
         int i, rc;
 
         /* Allocate and initialise a struct net_device and struct efx_nic */
-        net_dev = alloc_etherdev(sizeof(*efx));
+        net_dev = alloc_etherdev_mq(sizeof(*efx), EFX_MAX_CORE_TX_QUEUES);
         if (!net_dev)
                 return -ENOMEM;
         net_dev->features |= (type->offload_features | NETIF_F_SG |