From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932790Ab1EFAsR (ORCPT ); Thu, 5 May 2011 20:48:17 -0400 Received: from kroah.org ([198.145.64.141]:37012 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756024Ab1EFAZX (ORCPT ); Thu, 5 May 2011 20:25:23 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Thu May 5 17:22:13 2011 Message-Id: <20110506002213.749571650@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Thu, 05 May 2011 17:21:12 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "Michael S. Tsirkin" , Rusty Russell , "David S. Miller" Subject: [087/143] virtio_net: fix oom handling on tx In-Reply-To: <20110506002311.GA15354@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Rusty Russell commit 58eba97d0774c69b1cf3e5a8ac74419409d1abbf upstream. virtio net will never try to overflow the TX ring, so the only reason add_buf may fail is out of memory. Thus, we can not stop the device until some request completes - there's no guarantee anything at all is outstanding. Make the error message clearer as well: error here does not indicate queue full. Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/virtio_net.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -525,7 +525,6 @@ static netdev_tx_t start_xmit(struct sk_ struct virtnet_info *vi = netdev_priv(dev); int capacity; -again: /* Free up any pending old buffers before queueing new ones. */ free_old_xmit_skbs(vi); @@ -534,14 +533,20 @@ again: /* This can happen with OOM and indirect buffers. */ if (unlikely(capacity < 0)) { - netif_stop_queue(dev); - dev_warn(&dev->dev, "Unexpected full queue\n"); - if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) { - vi->svq->vq_ops->disable_cb(vi->svq); - netif_start_queue(dev); - goto again; + if (net_ratelimit()) { + if (likely(capacity == -ENOMEM)) { + dev_warn(&dev->dev, + "TX queue failure: out of memory\n"); + } else { + dev->stats.tx_fifo_errors++; + dev_warn(&dev->dev, + "Unexpected TX queue failure: %d\n", + capacity); + } } - return NETDEV_TX_BUSY; + dev->stats.tx_dropped++; + kfree_skb(skb); + return NETDEV_TX_OK; } vi->svq->vq_ops->kick(vi->svq);