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Commit 866b4f3e authored by Stephen Hemminger's avatar Stephen Hemminger Committed by Jeff Garzik
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[PATCH] skge: dont free skb until multi-part transmit complete 



Don't free transmit buffers until the whole set of transmit descriptors
has been marked as done.  Otherwise, we risk freeing a skb before the
whole transmit is done.

This changes the transmit completion handling from incremental to a
two pass algorithm. First pass scans and records the start of the last
done descriptor, second cleans up until that point.

Signed-off-by: default avatarStephen Hemminger <shemminger@osdl.org>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 4c180fc4

drivers/net/skge.c

+38 −35
Original line number Diff line number Diff line
@@ -2404,35 +2404,39 @@ static int skge_xmit_frame(struct sk_buff *skb, struct net_device *dev) 
	return NETDEV_TX_OK;

}



static inline void skge_tx_free(struct skge_hw *hw, struct skge_element *e)

static void skge_tx_complete(struct skge_port *skge, struct skge_element *last)

{

	/* This ring element can be skb or fragment */

	if (e->skb) {

		pci_unmap_single(hw->pdev,

			       pci_unmap_addr(e, mapaddr),

			       pci_unmap_len(e, maplen),

			       PCI_DMA_TODEVICE);

		dev_kfree_skb(e->skb);

	struct pci_dev *pdev = skge->hw->pdev;

	struct skge_element *e;



	for (e = skge->tx_ring.to_clean; e != last; e = e->next) {

		struct sk_buff *skb = e->skb;

		int i;



		e->skb = NULL;

	} else {

		pci_unmap_page(hw->pdev,

			       pci_unmap_addr(e, mapaddr),

			       pci_unmap_len(e, maplen),

		pci_unmap_single(pdev, pci_unmap_addr(e, mapaddr),

				 skb_headlen(skb), PCI_DMA_TODEVICE);

		++skge->tx_avail;



		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {

			e = e->next;

			pci_unmap_page(pdev, pci_unmap_addr(e, mapaddr),

				       skb_shinfo(skb)->frags[i].size,

				       PCI_DMA_TODEVICE);

			++skge->tx_avail;

		}



		dev_kfree_skb(skb);

	}

	skge->tx_ring.to_clean = e;

}



static void skge_tx_clean(struct skge_port *skge)

{

	struct skge_ring *ring = &skge->tx_ring;

	struct skge_element *e;



	spin_lock_bh(&skge->tx_lock);

	for (e = ring->to_clean; e != ring->to_use; e = e->next) {

		++skge->tx_avail;

		skge_tx_free(skge->hw, e);

	}

	ring->to_clean = e;

	skge_tx_complete(skge, skge->tx_ring.to_use);

	netif_wake_queue(skge->netdev);

	spin_unlock_bh(&skge->tx_lock);

}
@@ -2662,27 +2666,26 @@ resubmit: 
static void skge_tx_done(struct skge_port *skge)

{

	struct skge_ring *ring = &skge->tx_ring;

	struct skge_element *e;

	struct skge_element *e, *last;



	spin_lock(&skge->tx_lock);

	for (e = ring->to_clean; prefetch(e->next), e != ring->to_use; e = e->next) {

	last = ring->to_clean;

	for (e = ring->to_clean; e != ring->to_use; e = e->next) {

		struct skge_tx_desc *td = e->desc;

		u32 control;



		rmb();

		control = td->control;

		if (control & BMU_OWN)

		if (td->control & BMU_OWN)

			break;



		if (td->control & BMU_EOF) {

			last = e->next;

			if (unlikely(netif_msg_tx_done(skge)))

			printk(KERN_DEBUG PFX "%s: tx done slot %td status 0x%x\n",

			       skge->netdev->name, e - ring->start, td->status);



		skge_tx_free(skge->hw, e);

		e->skb = NULL;

		++skge->tx_avail;

				printk(KERN_DEBUG PFX "%s: tx done slot %td\n",

				       skge->netdev->name, e - ring->start);

		}

	ring->to_clean = e;

	}



	skge_tx_complete(skge, last);



	skge_write8(skge->hw, Q_ADDR(txqaddr[skge->port], Q_CSR), CSR_IRQ_CL_F);



	if (skge->tx_avail > MAX_SKB_FRAGS + 1)