X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=drivers%2Fnet%2Fsfc%2Ftx.c;h=2f5e9da657bf7cc66d1ad945d0c69340f19dada0;hb=abb359450f20c32ae03039d8736f12b1d561caf5;hp=c6942da2c99af75b6749c7b94edf7b8204cdc676;hpb=6b5b817f103450444f3f658a498f435d92a197e5;p=firefly-linux-kernel-4.4.55.git

diff --git a/drivers/net/sfc/tx.c b/drivers/net/sfc/tx.c
index c6942da2c99a..2f5e9da657bf 100644
--- a/drivers/net/sfc/tx.c
+++ b/drivers/net/sfc/tx.c
@@ -28,51 +28,7 @@
  * The tx_queue descriptor ring fill-level must fall below this value
  * before we restart the netif queue
  */
-#define EFX_TXQ_THRESHOLD (EFX_TXQ_MASK / 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;
-
-	if (!channel->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,
-			channel->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;
-
-	if (!channel->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,
-				channel->tx_queue->queue / EFX_TXQ_TYPES));
-		spin_unlock(&channel->tx_stop_lock);
-	}
-	local_bh_enable();
-}
+#define EFX_TXQ_THRESHOLD(_efx) ((_efx)->txq_entries / 2u)
 
 static void efx_dequeue_buffer(struct efx_tx_queue *tx_queue,
 			       struct efx_tx_buffer *buffer)
@@ -207,7 +163,7 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb)
 	}
 
 	fill_level = tx_queue->insert_count - tx_queue->old_read_count;
-	q_space = EFX_TXQ_MASK - 1 - fill_level;
+	q_space = efx->txq_entries - 1 - fill_level;
 
 	/* Map for DMA.  Use pci_map_single rather than pci_map_page
 	 * since this is more efficient on machines with sparse
@@ -234,24 +190,25 @@ 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_MASK - 1 - fill_level;
-				if (unlikely(q_space-- <= 0))
-					goto stop;
+				q_space = efx->txq_entries - 1 - fill_level;
+				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 & EFX_TXQ_MASK;
+			insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask;
 			buffer = &tx_queue->buffer[insert_ptr];
 			efx_tsoh_free(tx_queue, buffer);
 			EFX_BUG_ON_PARANOID(buffer->tsoh);
@@ -308,19 +265,12 @@ 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 */
 	while (tx_queue->insert_count != tx_queue->write_count) {
 		--tx_queue->insert_count;
-		insert_ptr = tx_queue->insert_count & EFX_TXQ_MASK;
+		insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask;
 		buffer = &tx_queue->buffer[insert_ptr];
 		efx_dequeue_buffer(tx_queue, buffer);
 		buffer->len = 0;
@@ -350,8 +300,8 @@ static void efx_dequeue_buffers(struct efx_tx_queue *tx_queue,
 	struct efx_nic *efx = tx_queue->efx;
 	unsigned int stop_index, read_ptr;
 
-	stop_index = (index + 1) & EFX_TXQ_MASK;
-	read_ptr = tx_queue->read_count & EFX_TXQ_MASK;
+	stop_index = (index + 1) & tx_queue->ptr_mask;
+	read_ptr = tx_queue->read_count & tx_queue->ptr_mask;
 
 	while (read_ptr != stop_index) {
 		struct efx_tx_buffer *buffer = &tx_queue->buffer[read_ptr];
@@ -368,7 +318,7 @@ static void efx_dequeue_buffers(struct efx_tx_queue *tx_queue,
 		buffer->len = 0;
 
 		++tx_queue->read_count;
-		read_ptr = tx_queue->read_count & EFX_TXQ_MASK;
+		read_ptr = tx_queue->read_count & tx_queue->ptr_mask;
 	}
 }
 
@@ -390,9 +340,9 @@ netdev_tx_t efx_hard_start_xmit(struct sk_buff *skb,
 	if (unlikely(efx->port_inhibited))
 		return NETDEV_TX_BUSY;
 
-	tx_queue = &efx->tx_queue[EFX_TXQ_TYPES * skb_get_queue_mapping(skb)];
-	if (likely(skb->ip_summed == CHECKSUM_PARTIAL))
-		tx_queue += EFX_TXQ_TYPE_OFFLOAD;
+	tx_queue = efx_get_tx_queue(efx, skb_get_queue_mapping(skb),
+				    skb->ip_summed == CHECKSUM_PARTIAL ?
+				    EFX_TXQ_TYPE_OFFLOAD : 0);
 
 	return efx_enqueue_skb(tx_queue, skb);
 }
@@ -402,27 +352,30 @@ void efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index)
 	unsigned fill_level;
 	struct efx_nic *efx = tx_queue->efx;
 
-	EFX_BUG_ON_PARANOID(index > EFX_TXQ_MASK);
+	EFX_BUG_ON_PARANOID(index > tx_queue->ptr_mask);
 
 	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) {
+		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;
 		}
 	}
 }
@@ -430,18 +383,24 @@ void efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index)
 int efx_probe_tx_queue(struct efx_tx_queue *tx_queue)
 {
 	struct efx_nic *efx = tx_queue->efx;
-	unsigned int txq_size;
+	unsigned int entries;
 	int i, rc;
 
-	netif_dbg(efx, probe, efx->net_dev, "creating TX queue %d\n",
-		  tx_queue->queue);
+	/* Create the smallest power-of-two aligned ring */
+	entries = max(roundup_pow_of_two(efx->txq_entries), EFX_MIN_DMAQ_SIZE);
+	EFX_BUG_ON_PARANOID(entries > EFX_MAX_DMAQ_SIZE);
+	tx_queue->ptr_mask = entries - 1;
+
+	netif_dbg(efx, probe, efx->net_dev,
+		  "creating TX queue %d size %#x mask %#x\n",
+		  tx_queue->queue, efx->txq_entries, tx_queue->ptr_mask);
 
 	/* Allocate software ring */
-	txq_size = EFX_TXQ_SIZE * sizeof(*tx_queue->buffer);
-	tx_queue->buffer = kzalloc(txq_size, GFP_KERNEL);
+	tx_queue->buffer = kzalloc(entries * sizeof(*tx_queue->buffer),
+				   GFP_KERNEL);
 	if (!tx_queue->buffer)
 		return -ENOMEM;
-	for (i = 0; i <= EFX_TXQ_MASK; ++i)
+	for (i = 0; i <= tx_queue->ptr_mask; ++i)
 		tx_queue->buffer[i].continuation = true;
 
 	/* Allocate hardware ring */
@@ -464,9 +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);
@@ -481,7 +441,7 @@ void efx_release_tx_buffers(struct efx_tx_queue *tx_queue)
 
 	/* Free any buffers left in the ring */
 	while (tx_queue->read_count != tx_queue->write_count) {
-		buffer = &tx_queue->buffer[tx_queue->read_count & EFX_TXQ_MASK];
+		buffer = &tx_queue->buffer[tx_queue->read_count & tx_queue->ptr_mask];
 		efx_dequeue_buffer(tx_queue, buffer);
 		buffer->continuation = true;
 		buffer->len = 0;
@@ -502,12 +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)
@@ -741,7 +695,7 @@ static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue,
 
 	fill_level = tx_queue->insert_count - tx_queue->old_read_count;
 	/* -1 as there is no way to represent all descriptors used */
-	q_space = EFX_TXQ_MASK - 1 - fill_level;
+	q_space = efx->txq_entries - 1 - fill_level;
 
 	while (1) {
 		if (unlikely(q_space-- <= 0)) {
@@ -749,30 +703,30 @@ 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_MASK - 1 - fill_level;
+			q_space = efx->txq_entries - 1 - fill_level;
 			if (unlikely(q_space-- <= 0)) {
 				*final_buffer = NULL;
 				return 1;
 			}
 			smp_mb();
-			--tx_queue->stopped;
+			netif_tx_start_queue(tx_queue->core_txq);
 		}
 
-		insert_ptr = tx_queue->insert_count & EFX_TXQ_MASK;
+		insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask;
 		buffer = &tx_queue->buffer[insert_ptr];
 		++tx_queue->insert_count;
 
 		EFX_BUG_ON_PARANOID(tx_queue->insert_count -
-				    tx_queue->read_count >
-				    EFX_TXQ_MASK);
+				    tx_queue->read_count >=
+				    efx->txq_entries);
 
 		efx_tsoh_free(tx_queue, buffer);
 		EFX_BUG_ON_PARANOID(buffer->len);
@@ -813,7 +767,7 @@ static void efx_tso_put_header(struct efx_tx_queue *tx_queue,
 {
 	struct efx_tx_buffer *buffer;
 
-	buffer = &tx_queue->buffer[tx_queue->insert_count & EFX_TXQ_MASK];
+	buffer = &tx_queue->buffer[tx_queue->insert_count & tx_queue->ptr_mask];
 	efx_tsoh_free(tx_queue, buffer);
 	EFX_BUG_ON_PARANOID(buffer->len);
 	EFX_BUG_ON_PARANOID(buffer->unmap_len);
@@ -838,7 +792,7 @@ static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue)
 	while (tx_queue->insert_count != tx_queue->write_count) {
 		--tx_queue->insert_count;
 		buffer = &tx_queue->buffer[tx_queue->insert_count &
-					   EFX_TXQ_MASK];
+					   tx_queue->ptr_mask];
 		efx_tsoh_free(tx_queue, buffer);
 		EFX_BUG_ON_PARANOID(buffer->skb);
 		if (buffer->unmap_len) {
@@ -1103,8 +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) {
@@ -1133,14 +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 */
@@ -1168,7 +1116,7 @@ static void efx_fini_tso(struct efx_tx_queue *tx_queue)
 	unsigned i;
 
 	if (tx_queue->buffer) {
-		for (i = 0; i <= EFX_TXQ_MASK; ++i)
+		for (i = 0; i <= tx_queue->ptr_mask; ++i)
 			efx_tsoh_free(tx_queue, &tx_queue->buffer[i]);
 	}