From mboxrd@z Thu Jan 1 00:00:00 1970 From: David L Stevens Subject: [PATCH net-next] sunvnet: improve error handling when a remote crashes Date: Mon, 26 Jan 2015 14:10:19 -0500 Message-ID: <54C6911B.5040501@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Sowmini Varadhan To: David Miller Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:23233 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755466AbbAZTKY (ORCPT ); Mon, 26 Jan 2015 14:10:24 -0500 Sender: netdev-owner@vger.kernel.org List-ID: 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: David L Stevens --- drivers/net/ethernet/sun/sunvnet.c | 68 +++++++++++++++++++++--------------- 1 files changed, 40 insertions(+), 28 deletions(-) diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c index fe044f3..3733ae6 100644 --- a/drivers/net/ethernet/sun/sunvnet.c +++ b/drivers/net/ethernet/sun/sunvnet.c @@ -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 @@ ldc_ctrl: 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; @@ -934,36 +933,36 @@ 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; - d = vio_dring_entry(dr, txi); - - if (d->hdr.state == VIO_DESC_DONE) { - if (port->tx_bufs[txi].skb) { - BUG_ON(port->tx_bufs[txi].skb->next); + --txi; + if (txi < 0) + txi = VNET_TX_RING_SIZE-1; - port->tx_bufs[txi].skb->next = skb; - skb = port->tx_bufs[txi].skb; - port->tx_bufs[txi].skb = NULL; + d = vio_dring_entry(dr, txi); - 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) { + if (d->hdr.state == VIO_DESC_READY) { (*pending)++; - } else if (d->hdr.state == VIO_DESC_FREE) { - break; + continue; } - --txi; - if (txi < 0) - txi = VNET_TX_RING_SIZE-1; + if (port->tx_bufs[txi].skb) { + if (d->hdr.state != VIO_DESC_DONE) + pr_warn("invalid ring buffer state %d\n", + d->hdr.state); + BUG_ON(port->tx_bufs[txi].skb->next); + + port->tx_bufs[txi].skb->next = skb; + skb = port->tx_bufs[txi].skb; + port->tx_bufs[txi].skb = NULL; + + ldc_unmap(port->vio.lp, + port->tx_bufs[txi].cookies, + port->tx_bufs[txi].ncookies); + } else if (d->hdr.state == VIO_DESC_FREE) + break; + d->hdr.state = VIO_DESC_FREE; } return skb; } @@ -1633,7 +1632,9 @@ static const struct ethtool_ops vnet_ethtool_ops = { static void vnet_port_free_tx_bufs(struct vnet_port *port) { + struct net_device *dev = port->vp->dev; struct vio_dring_state *dr; + bool active_freed = false; int i; dr = &port->vio.drings[VIO_DRIVER_TX_RING]; @@ -1649,8 +1650,7 @@ 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"); + active_freed |= d->hdr.state == VIO_DESC_READY; ldc_unmap(port->vio.lp, port->tx_bufs[i].cookies, @@ -1662,6 +1662,9 @@ static void vnet_port_free_tx_bufs(struct vnet_port *port) ldc_free_exp_dring(port->vio.lp, dr->base, (dr->entry_size * dr->num_entries), dr->cookies, dr->ncookies); + if (active_freed) + pr_warn("%s: active transmit buffers freed for remote %pM\n", + dev->name, port->raddr); dr->base = NULL; dr->entry_size = 0; dr->num_entries = 0; @@ -1669,6 +1672,15 @@ 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; -- 1.7.1