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Commit 8e2b60cd authored by David L Stevens's avatar David L Stevens Committed by David S. Miller
Browse files

sunvnet: improve error handling when a remote crashes 



If a remote machine crashes while there are pending transmit buffers, the
sunvnet driver reallocates the ring descriptors giving us enries that have
state VIO_DESC_FREE but also an allocated skb. This results in a BUG_ON()
call when the remote reboots and we reach that point in the ring.

This patch:

1) clears pending tx packets in the ring on port reset
2) changes a BUG_ON() to a pr_warn() when a remote host has given us an invalid
	descriptor state
3) collapses multiple active buffer frees in a ring to a single message per
	ring and adds the device name and remote MAC address

This fixes the particular problem of not cleaning up pending buffers on a
reset, but also prevents us from crashing if the remote handles descriptors
out of order or sets an unexpected state for a descriptor.

Signed-off-by: default avatarDavid L Stevens <david.stevens@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 07ac3e70

drivers/net/ethernet/sun/sunvnet.c

+34 −28
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ MODULE_VERSION(DRV_MODULE_VERSION); 
#define	VNET_MAX_RETRIES	10



static int __vnet_tx_trigger(struct vnet_port *port, u32 start);

static void vnet_port_reset(struct vnet_port *port);



/* Ordered from largest major to lowest */

static struct vio_version vnet_versions[] = {
@@ -736,9 +737,7 @@ static int vnet_event_napi(struct vnet_port *port, int budget) 
		vio_link_state_change(vio, event);



		if (event == LDC_EVENT_RESET) {

			port->rmtu = 0;

			port->tso = true;

			port->tsolen = 0;

			vnet_port_reset(port);

			vio_port_up(vio);

		}

		port->rx_event = 0;
@@ -934,17 +933,24 @@ static struct sk_buff *vnet_clean_tx_ring(struct vnet_port *port, 


	*pending = 0;



	txi = dr->prod-1;

	if (txi < 0)

		txi = VNET_TX_RING_SIZE-1;



	txi = dr->prod;

	for (i = 0; i < VNET_TX_RING_SIZE; ++i) {

		struct vio_net_desc *d;



		--txi;

		if (txi < 0)

			txi = VNET_TX_RING_SIZE-1;



		d = vio_dring_entry(dr, txi);



		if (d->hdr.state == VIO_DESC_DONE) {

		if (d->hdr.state == VIO_DESC_READY) {

			(*pending)++;

			continue;

		}

		if (port->tx_bufs[txi].skb) {

			if (d->hdr.state != VIO_DESC_DONE)

				pr_notice("invalid ring buffer state %d\n",

					  d->hdr.state);

			BUG_ON(port->tx_bufs[txi].skb->next);



			port->tx_bufs[txi].skb->next = skb;
@@ -954,16 +960,9 @@ static struct sk_buff *vnet_clean_tx_ring(struct vnet_port *port, 
			ldc_unmap(port->vio.lp,

				  port->tx_bufs[txi].cookies,

				  port->tx_bufs[txi].ncookies);

			}

			d->hdr.state = VIO_DESC_FREE;

		} else if (d->hdr.state == VIO_DESC_READY) {

			(*pending)++;

		} else if (d->hdr.state == VIO_DESC_FREE) {

		} else if (d->hdr.state == VIO_DESC_FREE)

			break;

		}

		--txi;

		if (txi < 0)

			txi = VNET_TX_RING_SIZE-1;

		d->hdr.state = VIO_DESC_FREE;

	}

	return skb;

}
@@ -1649,8 +1648,6 @@ static void vnet_port_free_tx_bufs(struct vnet_port *port) 
			continue;



		d = vio_dring_entry(dr, i);

		if (d->hdr.state == VIO_DESC_READY)

			pr_warn("active transmit buffers freed\n");



		ldc_unmap(port->vio.lp,

			  port->tx_bufs[i].cookies,
@@ -1669,6 +1666,15 @@ static void vnet_port_free_tx_bufs(struct vnet_port *port) 
	dr->ncookies = 0;

}



static void vnet_port_reset(struct vnet_port *port)

{

	del_timer(&port->clean_timer);

	vnet_port_free_tx_bufs(port);

	port->rmtu = 0;

	port->tso = true;

	port->tsolen = 0;

}



static int vnet_port_alloc_tx_ring(struct vnet_port *port)

{

	struct vio_dring_state *dr;