From patchwork Fri Aug 3 01:24:40 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ike Panhc X-Patchwork-Id: 174828 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from chlorine.canonical.com (chlorine.canonical.com [91.189.94.204]) by ozlabs.org (Postfix) with ESMTP id 54F122C0088 for ; Fri, 3 Aug 2012 11:24:54 +1000 (EST) Received: from localhost ([127.0.0.1] helo=chlorine.canonical.com) by chlorine.canonical.com with esmtp (Exim 4.71) (envelope-from ) id 1Sx6dE-0001Mw-8Q; Fri, 03 Aug 2012 01:24:48 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by chlorine.canonical.com with esmtp (Exim 4.71) (envelope-from ) id 1Sx6dC-0001Mg-Ds for kernel-team@lists.ubuntu.com; Fri, 03 Aug 2012 01:24:46 +0000 Received: from 220-134-16-35.hinet-ip.hinet.net ([220.134.16.35] helo=canonical.com) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1Sx6dB-0006Zl-Cy for kernel-team@lists.ubuntu.com; Fri, 03 Aug 2012 01:24:46 +0000 From: Ike Panhc To: kernel-team@lists.ubuntu.com Subject: [PATCH 07/14] UBUNTU: (drop after 3.6-rc1) net: calxedaxgmac: fix hang on rx refill Date: Fri, 3 Aug 2012 09:24:40 +0800 Message-Id: <1343957080-5493-1-git-send-email-ike.pan@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1343956968-5248-1-git-send-email-ike.pan@canonical.com> References: <1343956968-5248-1-git-send-email-ike.pan@canonical.com> X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.13 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: kernel-team-bounces@lists.ubuntu.com Errors-To: kernel-team-bounces@lists.ubuntu.com From: Rob Herring BugLink: http://launchpad.net/bugs/1008345 Fix intermittent hangs in xgmac_rx_refill. If a ring buffer entry already had an skb allocated, then xgmac_rx_refill would get stuck in a loop. This can happen on a rx error when we just leave the skb allocated to the entry. [ 7884.510000] INFO: rcu_preempt detected stall on CPU 0 (t=727315 jiffies) [ 7884.510000] [] (unwind_backtrace+0x1/0x98) from [] (__rcu_pending+0x11b/0x2c4) [ 7884.510000] [] (__rcu_pending+0x11b/0x2c4) from [] (rcu_check_callbacks+0xed/0x1a8) [ 7884.510000] [] (rcu_check_callbacks+0xed/0x1a8) from [] (update_process_times+0x2b/0x48) [ 7884.510000] [] (update_process_times+0x2b/0x48) from [] (tick_sched_timer+0x51/0x94) [ 7884.510000] [] (tick_sched_timer+0x51/0x94) from [] (__run_hrtimer+0x4f/0x1e8) [ 7884.510000] [] (__run_hrtimer+0x4f/0x1e8) from [] (hrtimer_interrupt+0xd7/0x1e4) [ 7884.510000] [] (hrtimer_interrupt+0xd7/0x1e4) from [] (twd_handler+0x17/0x24) [ 7884.510000] [] (twd_handler+0x17/0x24) from [] (handle_percpu_devid_irq+0x59/0x114) [ 7884.510000] [] (handle_percpu_devid_irq+0x59/0x114) from [] (generic_handle_irq+0x17/0x2c) [ 7884.510000] [] (generic_handle_irq+0x17/0x2c) from [] (handle_IRQ+0x35/0x7c) [ 7884.510000] [] (handle_IRQ+0x35/0x7c) from [] (__irq_svc+0x33/0xb8) [ 7884.510000] [] (__irq_svc+0x33/0xb8) from [] (xgmac_rx_refill+0x3a/0x140) [ 7884.510000] [] (xgmac_rx_refill+0x3a/0x140) from [] (xgmac_poll+0x265/0x3bc) [ 7884.510000] [] (xgmac_poll+0x265/0x3bc) from [] (net_rx_action+0xc3/0x200) [ 7884.510000] [] (net_rx_action+0xc3/0x200) from [] (__do_softirq+0xa3/0x1bc) Signed-off-by: Rob Herring Signed-off-by: David S. Miller (cherry picked from commit 7c4009192ea2276c1d7ed8ec0a18f3ecfca5cd2b) Signed-off-by: Ike Panhc --- drivers/net/ethernet/calxeda/xgmac.c | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c index dd08033..cd64c6b 100644 --- a/drivers/net/ethernet/calxeda/xgmac.c +++ b/drivers/net/ethernet/calxeda/xgmac.c @@ -671,26 +671,23 @@ static void xgmac_rx_refill(struct xgmac_priv *priv) p = priv->dma_rx + entry; - if (priv->rx_skbuff[entry] != NULL) - continue; - - skb = __skb_dequeue(&priv->rx_recycle); - if (skb == NULL) - skb = netdev_alloc_skb(priv->dev, priv->dma_buf_sz); - if (unlikely(skb == NULL)) - break; - - priv->rx_skbuff[entry] = skb; - paddr = dma_map_single(priv->device, skb->data, - priv->dma_buf_sz, DMA_FROM_DEVICE); - desc_set_buf_addr(p, paddr, priv->dma_buf_sz); + if (priv->rx_skbuff[entry] == NULL) { + skb = __skb_dequeue(&priv->rx_recycle); + if (skb == NULL) + skb = netdev_alloc_skb(priv->dev, priv->dma_buf_sz); + if (unlikely(skb == NULL)) + break; + + priv->rx_skbuff[entry] = skb; + paddr = dma_map_single(priv->device, skb->data, + priv->dma_buf_sz, DMA_FROM_DEVICE); + desc_set_buf_addr(p, paddr, priv->dma_buf_sz); + } netdev_dbg(priv->dev, "rx ring: head %d, tail %d\n", priv->rx_head, priv->rx_tail); priv->rx_head = dma_ring_incr(priv->rx_head, DMA_RX_RING_SZ); - /* Ensure descriptor is in memory before handing to h/w */ - wmb(); desc_set_rx_owner(p); } }