Exemplo n.º 1
0
/**
 * efx_enqueue_skb_tso - segment and transmit a TSO socket buffer
 * @tx_queue:		Efx TX queue
 * @skb:		Socket buffer
 *
 * Context: You must hold netif_tx_lock() to call this function.
 *
 * Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if
 * @skb was not enqueued.  In all cases @skb is consumed.  Return
 * %NETDEV_TX_OK or %NETDEV_TX_BUSY.
 */
static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
			       const struct sk_buff *skb)
{
	int frag_i, rc, rc2 = NETDEV_TX_OK;
	struct tso_state state;
	skb_frag_t *f;

	/* Verify TSO is safe - these checks should never fail. */
	efx_tso_check_safe(skb);

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

	tso_start(&state, skb);

	/* Assume that skb header area contains exactly the headers, and
	 * all payload is in the frag list.
	 */
	if (skb_headlen(skb) == state.p.header_length) {
		/* Grab the first payload fragment. */
		EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1);
		frag_i = 0;
		f = &skb_shinfo(skb)->frags[frag_i];
		rc = tso_get_fragment(&state, tx_queue->efx,
				      f->size, f->page, f->page_offset);
		if (rc)
			goto mem_err;
	} else {
		/* It may look like this code fragment assumes that the
		 * skb->data portion does not cross a page boundary, but
		 * that is not the case.  It is guaranteed to be direct
		 * mapped memory, and therefore is physically contiguous,
		 * and so DMA will work fine.  kmap_atomic() on this region
		 * will just return the direct mapping, so that will work
		 * too.
		 */
		int page_off = (unsigned long)skb->data & (PAGE_SIZE - 1);
		int hl = state.p.header_length;
		rc = tso_get_fragment(&state, tx_queue->efx,
				      skb_headlen(skb) - hl,
				      virt_to_page(skb->data), page_off + hl);
		if (rc)
			goto mem_err;
		frag_i = -1;
	}

	if (tso_start_new_packet(tx_queue, skb, &state) < 0)
		goto mem_err;

	while (1) {
		rc = tso_fill_packet_with_fragment(tx_queue, skb, &state);
		if (unlikely(rc))
			goto stop;

		/* Move onto the next fragment? */
		if (state.ifc.len == 0) {
			if (++frag_i >= skb_shinfo(skb)->nr_frags)
				/* End of payload reached. */
				break;
			f = &skb_shinfo(skb)->frags[frag_i];
			rc = tso_get_fragment(&state, tx_queue->efx,
					      f->size, f->page, f->page_offset);
			if (rc)
				goto mem_err;
		}

		/* Start at new packet? */
		if (state.packet_space == 0 &&
		    tso_start_new_packet(tx_queue, skb, &state) < 0)
			goto mem_err;
	}

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

	tx_queue->tso_bursts++;
	return NETDEV_TX_OK;

 mem_err:
	EFX_ERR(tx_queue->efx, "Out of memory for TSO headers, or PCI mapping"
		" error\n");
	dev_kfree_skb_any((struct sk_buff *)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->efx);

 unwind:
	efx_enqueue_unwind(tx_queue);
	return rc2;
}
Exemplo n.º 2
0
/**
 * efx_enqueue_skb_tso - segment and transmit a TSO socket buffer
 * @tx_queue:		Efx TX queue
 * @skb:		Socket buffer
 *
 * Context: You must hold netif_tx_lock() to call this function.
 *
 * Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if
 * @skb was not enqueued.  In all cases @skb is consumed.  Return
 * %NETDEV_TX_OK or %NETDEV_TX_BUSY.
 */
static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
			       struct sk_buff *skb)
{
	struct efx_nic *efx = tx_queue->efx;
	int frag_i, rc, rc2 = NETDEV_TX_OK;
	struct tso_state state;

	/* Find the packet protocol and sanity-check it */
	state.protocol = efx_tso_check_protocol(skb);

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

	tso_start(&state, skb);

	/* Assume that skb header area contains exactly the headers, and
	 * all payload is in the frag list.
	 */
	if (skb_headlen(skb) == state.header_len) {
		/* Grab the first payload fragment. */
		EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1);
		frag_i = 0;
		rc = tso_get_fragment(&state, efx,
				      skb_shinfo(skb)->frags + frag_i);
		if (rc)
			goto mem_err;
	} else {
		rc = tso_get_head_fragment(&state, efx, skb);
		if (rc)
			goto mem_err;
		frag_i = -1;
	}

	if (tso_start_new_packet(tx_queue, skb, &state) < 0)
		goto mem_err;

	while (1) {
		rc = tso_fill_packet_with_fragment(tx_queue, skb, &state);
		if (unlikely(rc)) {
			rc2 = NETDEV_TX_BUSY;
			goto unwind;
		}

		/* Move onto the next fragment? */
		if (state.in_len == 0) {
			if (++frag_i >= skb_shinfo(skb)->nr_frags)
				/* End of payload reached. */
				break;
			rc = tso_get_fragment(&state, efx,
					      skb_shinfo(skb)->frags + frag_i);
			if (rc)
				goto mem_err;
		}

		/* Start at new packet? */
		if (state.packet_space == 0 &&
		    tso_start_new_packet(tx_queue, skb, &state) < 0)
			goto mem_err;
	}

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

	tx_queue->tso_bursts++;
	return NETDEV_TX_OK;

 mem_err:
	netif_err(efx, tx_err, efx->net_dev,
		  "Out of memory for TSO headers, or PCI mapping error\n");
	dev_kfree_skb_any(skb);

 unwind:
	/* Free the DMA mapping we were in the process of writing out */
	if (state.unmap_len) {
		if (state.unmap_single)
			pci_unmap_single(efx->pci_dev, state.unmap_addr,
					 state.unmap_len, PCI_DMA_TODEVICE);
		else
			pci_unmap_page(efx->pci_dev, state.unmap_addr,
				       state.unmap_len, PCI_DMA_TODEVICE);
	}

	efx_enqueue_unwind(tx_queue);
	return rc2;
}
Exemplo n.º 3
0
/**
 * efx_enqueue_skb_tso - segment and transmit a TSO socket buffer
 * @tx_queue:		Efx TX queue
 * @skb:		Socket buffer
 *
 * Context: You must hold netif_tx_lock() to call this function.
 *
 * Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if
 * @skb was not enqueued.  In all cases @skb is consumed.  Return
 * %NETDEV_TX_OK or %NETDEV_TX_BUSY.
 */
static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
			       struct sk_buff *skb)
{
	struct efx_nic *efx = tx_queue->efx;
	int frag_i, rc, rc2 = NETDEV_TX_OK;
	struct tso_state state;

	/* Since the stack does not limit the number of segments per
	 * skb, we must do so.  Otherwise an attacker may be able to
	 * make the TCP produce skbs that will never fit in our TX
	 * queue, causing repeated resets.
	 */
	if (unlikely(skb_shinfo(skb)->gso_segs > EFX_TSO_MAX_SEGS)) {
		unsigned int excess =
			(skb_shinfo(skb)->gso_segs - EFX_TSO_MAX_SEGS) *
			skb_shinfo(skb)->gso_size;
		if (__pskb_trim(skb, skb->len - excess)) {
			dev_kfree_skb_any(skb);
			return NETDEV_TX_OK;
		}
	}

	/* Find the packet protocol and sanity-check it */
	state.protocol = efx_tso_check_protocol(skb);

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

	tso_start(&state, skb);

	/* Assume that skb header area contains exactly the headers, and
	 * all payload is in the frag list.
	 */
	if (skb_headlen(skb) == state.header_len) {
		/* Grab the first payload fragment. */
		EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1);
		frag_i = 0;
		rc = tso_get_fragment(&state, efx,
				      skb_shinfo(skb)->frags + frag_i);
		if (rc)
			goto mem_err;
	} else {
		rc = tso_get_head_fragment(&state, efx, skb);
		if (rc)
			goto mem_err;
		frag_i = -1;
	}

	if (tso_start_new_packet(tx_queue, skb, &state) < 0)
		goto mem_err;

	while (1) {
		rc = tso_fill_packet_with_fragment(tx_queue, skb, &state);
		if (unlikely(rc)) {
			rc2 = NETDEV_TX_BUSY;
			goto unwind;
		}

		/* Move onto the next fragment? */
		if (state.in_len == 0) {
			if (++frag_i >= skb_shinfo(skb)->nr_frags)
				/* End of payload reached. */
				break;
			rc = tso_get_fragment(&state, efx,
					      skb_shinfo(skb)->frags + frag_i);
			if (rc)
				goto mem_err;
		}

		/* Start at new packet? */
		if (state.packet_space == 0 &&
		    tso_start_new_packet(tx_queue, skb, &state) < 0)
			goto mem_err;
	}

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

	tx_queue->tso_bursts++;
	return NETDEV_TX_OK;

 mem_err:
	netif_err(efx, tx_err, efx->net_dev,
		  "Out of memory for TSO headers, or PCI mapping error\n");
	dev_kfree_skb_any(skb);

 unwind:
	/* Free the DMA mapping we were in the process of writing out */
	if (state.unmap_len) {
		if (state.unmap_single)
			pci_unmap_single(efx->pci_dev, state.unmap_addr,
					 state.unmap_len, PCI_DMA_TODEVICE);
		else
			pci_unmap_page(efx->pci_dev, state.unmap_addr,
				       state.unmap_len, PCI_DMA_TODEVICE);
	}

	efx_enqueue_unwind(tx_queue);
	return rc2;
}