diff options
Diffstat (limited to 'drivers/net/sfc/tx.c')
| -rw-r--r-- | drivers/net/sfc/tx.c | 122 |
1 files changed, 32 insertions, 90 deletions
diff --git a/drivers/net/sfc/tx.c b/drivers/net/sfc/tx.c index 11726989fe2d..2f5e9da657bf 100644 --- a/drivers/net/sfc/tx.c +++ b/drivers/net/sfc/tx.c @@ -30,50 +30,6 @@ */ #define EFX_TXQ_THRESHOLD(_efx) ((_efx)->txq_entries / 2u) -/* We need to be able to nest calls to netif_tx_stop_queue(), partly - * because of the 2 hardware queues associated with each core queue, - * but also so that we can inhibit TX for reasons other than a full - * hardware queue. */ -void efx_stop_queue(struct efx_channel *channel) -{ - struct efx_nic *efx = channel->efx; - struct efx_tx_queue *tx_queue = efx_channel_get_tx_queue(channel, 0); - - if (!tx_queue) - return; - - spin_lock_bh(&channel->tx_stop_lock); - netif_vdbg(efx, tx_queued, efx->net_dev, "stop TX queue\n"); - - atomic_inc(&channel->tx_stop_count); - netif_tx_stop_queue( - netdev_get_tx_queue(efx->net_dev, - tx_queue->queue / EFX_TXQ_TYPES)); - - spin_unlock_bh(&channel->tx_stop_lock); -} - -/* Decrement core TX queue stop count and wake it if the count is 0 */ -void efx_wake_queue(struct efx_channel *channel) -{ - struct efx_nic *efx = channel->efx; - struct efx_tx_queue *tx_queue = efx_channel_get_tx_queue(channel, 0); - - if (!tx_queue) - return; - - local_bh_disable(); - if (atomic_dec_and_lock(&channel->tx_stop_count, - &channel->tx_stop_lock)) { - netif_vdbg(efx, tx_queued, efx->net_dev, "waking TX queue\n"); - netif_tx_wake_queue( - netdev_get_tx_queue(efx->net_dev, - tx_queue->queue / EFX_TXQ_TYPES)); - spin_unlock(&channel->tx_stop_lock); - } - local_bh_enable(); -} - static void efx_dequeue_buffer(struct efx_tx_queue *tx_queue, struct efx_tx_buffer *buffer) { @@ -234,21 +190,22 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb) * checked. Update the xmit path's * copy of read_count. */ - ++tx_queue->stopped; + netif_tx_stop_queue(tx_queue->core_txq); /* This memory barrier protects the - * change of stopped from the access + * change of queue state from the access * of read_count. */ smp_mb(); tx_queue->old_read_count = - *(volatile unsigned *) - &tx_queue->read_count; + ACCESS_ONCE(tx_queue->read_count); fill_level = (tx_queue->insert_count - tx_queue->old_read_count); q_space = efx->txq_entries - 1 - fill_level; - if (unlikely(q_space-- <= 0)) - goto stop; + if (unlikely(q_space-- <= 0)) { + rc = NETDEV_TX_BUSY; + goto unwind; + } smp_mb(); - --tx_queue->stopped; + netif_tx_start_queue(tx_queue->core_txq); } insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask; @@ -308,13 +265,6 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb) /* Mark the packet as transmitted, and free the SKB ourselves */ dev_kfree_skb_any(skb); - goto unwind; - - stop: - rc = NETDEV_TX_BUSY; - - if (tx_queue->stopped == 1) - efx_stop_queue(tx_queue->channel); unwind: /* Work backwards until we hit the original insert pointer value */ @@ -407,22 +357,25 @@ void efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index) efx_dequeue_buffers(tx_queue, index); /* See if we need to restart the netif queue. This barrier - * separates the update of read_count from the test of - * stopped. */ + * separates the update of read_count from the test of the + * queue state. */ smp_mb(); - if (unlikely(tx_queue->stopped) && likely(efx->port_enabled)) { + if (unlikely(netif_tx_queue_stopped(tx_queue->core_txq)) && + likely(efx->port_enabled)) { fill_level = tx_queue->insert_count - tx_queue->read_count; if (fill_level < EFX_TXQ_THRESHOLD(efx)) { EFX_BUG_ON_PARANOID(!efx_dev_registered(efx)); + netif_tx_wake_queue(tx_queue->core_txq); + } + } - /* Do this under netif_tx_lock(), to avoid racing - * with efx_xmit(). */ - netif_tx_lock(efx->net_dev); - if (tx_queue->stopped) { - tx_queue->stopped = 0; - efx_wake_queue(tx_queue->channel); - } - netif_tx_unlock(efx->net_dev); + /* Check whether the hardware queue is now empty */ + if ((int)(tx_queue->read_count - tx_queue->old_write_count) >= 0) { + tx_queue->old_write_count = ACCESS_ONCE(tx_queue->write_count); + if (tx_queue->read_count == tx_queue->old_write_count) { + smp_mb(); + tx_queue->empty_read_count = + tx_queue->read_count | EFX_EMPTY_COUNT_VALID; } } } @@ -470,9 +423,10 @@ void efx_init_tx_queue(struct efx_tx_queue *tx_queue) tx_queue->insert_count = 0; tx_queue->write_count = 0; + tx_queue->old_write_count = 0; tx_queue->read_count = 0; tx_queue->old_read_count = 0; - BUG_ON(tx_queue->stopped); + tx_queue->empty_read_count = 0 | EFX_EMPTY_COUNT_VALID; /* Set up TX descriptor ring */ efx_nic_init_tx(tx_queue); @@ -508,12 +462,6 @@ void efx_fini_tx_queue(struct efx_tx_queue *tx_queue) /* Free up TSO header cache */ efx_fini_tso(tx_queue); - - /* Release queue's stop on port, if any */ - if (tx_queue->stopped) { - tx_queue->stopped = 0; - efx_wake_queue(tx_queue->channel); - } } void efx_remove_tx_queue(struct efx_tx_queue *tx_queue) @@ -755,12 +703,12 @@ static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue, * since the xmit path last checked. Update * the xmit path's copy of read_count. */ - ++tx_queue->stopped; + netif_tx_stop_queue(tx_queue->core_txq); /* This memory barrier protects the change of - * stopped from the access of read_count. */ + * queue state from the access of read_count. */ smp_mb(); tx_queue->old_read_count = - *(volatile unsigned *)&tx_queue->read_count; + ACCESS_ONCE(tx_queue->read_count); fill_level = (tx_queue->insert_count - tx_queue->old_read_count); q_space = efx->txq_entries - 1 - fill_level; @@ -769,7 +717,7 @@ static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue, return 1; } smp_mb(); - --tx_queue->stopped; + netif_tx_start_queue(tx_queue->core_txq); } insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask; @@ -1109,8 +1057,10 @@ static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue, while (1) { rc = tso_fill_packet_with_fragment(tx_queue, skb, &state); - if (unlikely(rc)) - goto stop; + if (unlikely(rc)) { + rc2 = NETDEV_TX_BUSY; + goto unwind; + } /* Move onto the next fragment? */ if (state.in_len == 0) { @@ -1139,14 +1089,6 @@ static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue, netif_err(efx, tx_err, efx->net_dev, "Out of memory for TSO headers, or PCI mapping error\n"); dev_kfree_skb_any(skb); - goto unwind; - - stop: - rc2 = NETDEV_TX_BUSY; - - /* Stop the queue if it wasn't stopped before. */ - if (tx_queue->stopped == 1) - efx_stop_queue(tx_queue->channel); unwind: /* Free the DMA mapping we were in the process of writing out */ |