예제 #1
0
파일: tx.c 프로젝트: ANFS/ANFS-kernel
/*
 * Add a socket buffer to a TX queue
 *
 * This maps all fragments of a socket buffer for DMA and adds them to
 * the TX queue.  The queue's insert pointer will be incremented by
 * the number of fragments in the socket buffer.
 *
 * If any DMA mapping fails, any mapped fragments will be unmapped,
 * the queue's insert pointer will be restored to its original value.
 *
 * This function is split out from efx_hard_start_xmit to allow the
 * loopback test to direct packets via specific TX queues.
 *
 * Returns NETDEV_TX_OK or NETDEV_TX_BUSY
 * You must hold netif_tx_lock() to call this function.
 */
netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb)
{
	struct efx_nic *efx = tx_queue->efx;
	struct pci_dev *pci_dev = efx->pci_dev;
	struct efx_tx_buffer *buffer;
	skb_frag_t *fragment;
	struct page *page;
	int page_offset;
	unsigned int len, unmap_len = 0, fill_level, insert_ptr;
	dma_addr_t dma_addr, unmap_addr = 0;
	unsigned int dma_len;
	bool unmap_single;
	int q_space, i = 0;
	netdev_tx_t rc = NETDEV_TX_OK;

	EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);

	if (skb_shinfo(skb)->gso_size)
		return efx_enqueue_skb_tso(tx_queue, skb);

	/* Get size of the initial fragment */
	len = skb_headlen(skb);

	/* Pad if necessary */
	if (EFX_WORKAROUND_15592(efx) && skb->len <= 32) {
		EFX_BUG_ON_PARANOID(skb->data_len);
		len = 32 + 1;
		if (skb_pad(skb, len - skb->len))
			return NETDEV_TX_OK;
	}

	fill_level = tx_queue->insert_count - tx_queue->old_read_count;
	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
	 * memory.
	 */
	unmap_single = true;
	dma_addr = pci_map_single(pci_dev, skb->data, len, PCI_DMA_TODEVICE);

	/* Process all fragments */
	while (1) {
		if (unlikely(pci_dma_mapping_error(pci_dev, dma_addr)))
			goto pci_err;

		/* Store fields for marking in the per-fragment final
		 * descriptor */
		unmap_len = len;
		unmap_addr = dma_addr;

		/* Add to TX queue, splitting across DMA boundaries */
		do {
			if (unlikely(q_space-- <= 0)) {
				/* It might be that completions have
				 * happened since the xmit path last
				 * checked.  Update the xmit path's
				 * copy of read_count.
				 */
				netif_tx_stop_queue(tx_queue->core_txq);
				/* This memory barrier protects the
				 * change of queue state from the access
				 * of read_count. */
				smp_mb();
				tx_queue->old_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)) {
					rc = NETDEV_TX_BUSY;
					goto unwind;
				}
				smp_mb();
				netif_tx_start_queue(tx_queue->core_txq);
			}

			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);
			EFX_BUG_ON_PARANOID(buffer->skb);
			EFX_BUG_ON_PARANOID(buffer->len);
			EFX_BUG_ON_PARANOID(!buffer->continuation);
			EFX_BUG_ON_PARANOID(buffer->unmap_len);

			dma_len = efx_max_tx_len(efx, dma_addr);
			if (likely(dma_len >= len))
				dma_len = len;

			/* Fill out per descriptor fields */
			buffer->len = dma_len;
			buffer->dma_addr = dma_addr;
			len -= dma_len;
			dma_addr += dma_len;
			++tx_queue->insert_count;
		} while (len);

		/* Transfer ownership of the unmapping to the final buffer */
		buffer->unmap_single = unmap_single;
		buffer->unmap_len = unmap_len;
		unmap_len = 0;

		/* Get address and size of next fragment */
		if (i >= skb_shinfo(skb)->nr_frags)
			break;
		fragment = &skb_shinfo(skb)->frags[i];
		len = fragment->size;
		page = fragment->page;
		page_offset = fragment->page_offset;
		i++;
		/* Map for DMA */
		unmap_single = false;
		dma_addr = pci_map_page(pci_dev, page, page_offset, len,
					PCI_DMA_TODEVICE);
	}

	/* Transfer ownership of the skb to the final buffer */
	buffer->skb = skb;
	buffer->continuation = false;

	/* Pass off to hardware */
	efx_nic_push_buffers(tx_queue);

	return NETDEV_TX_OK;

 pci_err:
	netif_err(efx, tx_err, efx->net_dev,
		  " TX queue %d could not map skb with %d bytes %d "
		  "fragments for DMA\n", tx_queue->queue, skb->len,
		  skb_shinfo(skb)->nr_frags + 1);

	/* Mark the packet as transmitted, and free the SKB ourselves */
	dev_kfree_skb_any(skb);

 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 & tx_queue->ptr_mask;
		buffer = &tx_queue->buffer[insert_ptr];
		efx_dequeue_buffer(tx_queue, buffer);
		buffer->len = 0;
	}

	/* Free the fragment we were mid-way through pushing */
	if (unmap_len) {
		if (unmap_single)
			pci_unmap_single(pci_dev, unmap_addr, unmap_len,
					 PCI_DMA_TODEVICE);
		else
			pci_unmap_page(pci_dev, unmap_addr, unmap_len,
				       PCI_DMA_TODEVICE);
	}

	return rc;
}
예제 #2
0
/*
 * Add a socket buffer to a TX queue
 *
 * This maps all fragments of a socket buffer for DMA and adds them to
 * the TX queue.  The queue's insert pointer will be incremented by
 * the number of fragments in the socket buffer.
 *
 * If any DMA mapping fails, any mapped fragments will be unmapped,
 * the queue's insert pointer will be restored to its original value.
 *
 * Returns NETDEV_TX_OK or NETDEV_TX_BUSY
 * You must hold netif_tx_lock() to call this function.
 */
static inline int efx_enqueue_skb(struct efx_tx_queue *tx_queue,
				  const struct sk_buff *skb)
{
	struct efx_nic *efx = tx_queue->efx;
	struct pci_dev *pci_dev = efx->pci_dev;
	struct efx_tx_buffer *buffer;
	skb_frag_t *fragment;
	struct page *page;
	int page_offset;
	unsigned int len, unmap_len = 0, fill_level, insert_ptr, misalign;
	dma_addr_t dma_addr, unmap_addr = 0;
	unsigned int dma_len;
	unsigned unmap_single;
	int q_space, i = 0;
	int rc = NETDEV_TX_OK;

	EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);

	if (skb_shinfo((struct sk_buff *)skb)->gso_size)
		return efx_enqueue_skb_tso(tx_queue, skb);

	/* Get size of the initial fragment */
	len = skb_headlen(skb);

	fill_level = tx_queue->insert_count - tx_queue->old_read_count;
	q_space = efx->type->txd_ring_mask - 1 - fill_level;

	/* Map for DMA.  Use pci_map_single rather than pci_map_page
	 * since this is more efficient on machines with sparse
	 * memory.
	 */
	unmap_single = 1;
	dma_addr = pci_map_single(pci_dev, skb->data, len, PCI_DMA_TODEVICE);

	/* Process all fragments */
	while (1) {
		if (unlikely(pci_dma_mapping_error(pci_dev, dma_addr)))
			goto pci_err;

		/* Store fields for marking in the per-fragment final
		 * descriptor */
		unmap_len = len;
		unmap_addr = dma_addr;

		/* Add to TX queue, splitting across DMA boundaries */
		do {
			if (unlikely(q_space-- <= 0)) {
				/* It might be that completions have
				 * happened since the xmit path last
				 * checked.  Update the xmit path's
				 * copy of read_count.
				 */
				++tx_queue->stopped;
				/* This memory barrier protects the
				 * change of stopped from the access
				 * of read_count. */
				smp_mb();
				tx_queue->old_read_count =
					*(volatile unsigned *)
					&tx_queue->read_count;
				fill_level = (tx_queue->insert_count
					      - tx_queue->old_read_count);
				q_space = (efx->type->txd_ring_mask - 1 -
					   fill_level);
				if (unlikely(q_space-- <= 0))
					goto stop;
				smp_mb();
				--tx_queue->stopped;
			}

			insert_ptr = (tx_queue->insert_count &
				      efx->type->txd_ring_mask);
			buffer = &tx_queue->buffer[insert_ptr];
			efx_tsoh_free(tx_queue, buffer);
			EFX_BUG_ON_PARANOID(buffer->tsoh);
			EFX_BUG_ON_PARANOID(buffer->skb);
			EFX_BUG_ON_PARANOID(buffer->len);
			EFX_BUG_ON_PARANOID(buffer->continuation != 1);
			EFX_BUG_ON_PARANOID(buffer->unmap_len);

			dma_len = (((~dma_addr) & efx->type->tx_dma_mask) + 1);
			if (likely(dma_len > len))
				dma_len = len;

			misalign = (unsigned)dma_addr & efx->type->bug5391_mask;
			if (misalign && dma_len + misalign > 512)
				dma_len = 512 - misalign;

			/* Fill out per descriptor fields */
			buffer->len = dma_len;
			buffer->dma_addr = dma_addr;
			len -= dma_len;
			dma_addr += dma_len;
			++tx_queue->insert_count;
		} while (len);

		/* Transfer ownership of the unmapping to the final buffer */
		buffer->unmap_addr = unmap_addr;
		buffer->unmap_single = unmap_single;
		buffer->unmap_len = unmap_len;
		unmap_len = 0;

		/* Get address and size of next fragment */
		if (i >= skb_shinfo(skb)->nr_frags)
			break;
		fragment = &skb_shinfo(skb)->frags[i];
		len = fragment->size;
		page = fragment->page;
		page_offset = fragment->page_offset;
		i++;
		/* Map for DMA */
		unmap_single = 0;
		dma_addr = pci_map_page(pci_dev, page, page_offset, len,
					PCI_DMA_TODEVICE);
	}

	/* Transfer ownership of the skb to the final buffer */
	buffer->skb = skb;
	buffer->continuation = 0;

	/* Pass off to hardware */
	falcon_push_buffers(tx_queue);

	return NETDEV_TX_OK;

 pci_err:
	EFX_ERR_RL(efx, " TX queue %d could not map skb with %d bytes %d "
		   "fragments for DMA\n", tx_queue->queue, skb->len,
		   skb_shinfo(skb)->nr_frags + 1);

	/* Mark the packet as transmitted, and free the SKB ourselves */
	dev_kfree_skb_any((struct sk_buff *)skb);
	goto unwind;

 stop:
	rc = NETDEV_TX_BUSY;

	if (tx_queue->stopped == 1)
		efx_stop_queue(efx);

 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->type->txd_ring_mask;
		buffer = &tx_queue->buffer[insert_ptr];
		efx_dequeue_buffer(tx_queue, buffer);
		buffer->len = 0;
	}

	/* Free the fragment we were mid-way through pushing */
	if (unmap_len)
		pci_unmap_page(pci_dev, unmap_addr, unmap_len,
			       PCI_DMA_TODEVICE);

	return rc;
}