From patchwork Mon Mar 11 17:39:39 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bryan Whitehead X-Patchwork-Id: 1054647 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=microchip.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44J55B5ZsXz9s3q for ; Tue, 12 Mar 2019 04:41:50 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727110AbfCKRlt (ORCPT ); Mon, 11 Mar 2019 13:41:49 -0400 Received: from esa4.microchip.iphmx.com ([68.232.154.123]:31701 "EHLO esa4.microchip.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726864AbfCKRls (ORCPT ); Mon, 11 Mar 2019 13:41:48 -0400 X-IronPort-AV: E=Sophos;i="5.58,468,1544511600"; d="scan'208";a="27587334" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa4.microchip.iphmx.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 11 Mar 2019 10:41:48 -0700 Received: from BW-Ubuntu-tester.mchp-main.com (10.10.76.4) by chn-sv-exch06.mchp-main.com (10.10.76.107) with Microsoft SMTP Server id 14.3.352.0; Mon, 11 Mar 2019 10:41:47 -0700 From: Bryan Whitehead To: CC: , Subject: [PATCH v2 net] lan743x: Fix RX Kernel Panic Date: Mon, 11 Mar 2019 13:39:39 -0400 Message-ID: <1552325979-27180-1-git-send-email-Bryan.Whitehead@microchip.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org It has been noticed that running the speed test at www.speedtest.net occasionally causes a kernel panic. Investigation revealed that under this test RX buffer allocation sometimes fails and returns NULL. But the lan743x driver did not handle this case. This patch fixes this issue by attempting to allocate a buffer before sending the new rx packet to the OS. If the allocation fails then the new rx packet is dropped and the existing buffer is reused in the DMA ring. Updates for v2: Additional 2 locations where allocation was not checked, has been changed to reuse existing buffer. Fixes: 23f0703c125b ("lan743x: Add main source files for new lan743x driver") Signed-off-by: Bryan Whitehead --- drivers/net/ethernet/microchip/lan743x_main.c | 46 +++++++++++++++++++-------- 1 file changed, 32 insertions(+), 14 deletions(-) diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c index 4d1b4a2..2876bab 100644 --- a/drivers/net/ethernet/microchip/lan743x_main.c +++ b/drivers/net/ethernet/microchip/lan743x_main.c @@ -1902,7 +1902,17 @@ static int lan743x_rx_next_index(struct lan743x_rx *rx, int index) return ((++index) % rx->ring_size); } -static int lan743x_rx_allocate_ring_element(struct lan743x_rx *rx, int index) +static struct sk_buff *lan743x_rx_allocate_skb(struct lan743x_rx *rx) +{ + int length = 0; + + length = (LAN743X_MAX_FRAME_SIZE + ETH_HLEN + 4 + RX_HEAD_PADDING); + return __netdev_alloc_skb(rx->adapter->netdev, + length, GFP_ATOMIC | GFP_DMA); +} + +static int lan743x_rx_init_ring_element(struct lan743x_rx *rx, int index, + struct sk_buff *skb) { struct lan743x_rx_buffer_info *buffer_info; struct lan743x_rx_descriptor *descriptor; @@ -1911,9 +1921,7 @@ static int lan743x_rx_allocate_ring_element(struct lan743x_rx *rx, int index) length = (LAN743X_MAX_FRAME_SIZE + ETH_HLEN + 4 + RX_HEAD_PADDING); descriptor = &rx->ring_cpu_ptr[index]; buffer_info = &rx->buffer_info[index]; - buffer_info->skb = __netdev_alloc_skb(rx->adapter->netdev, - length, - GFP_ATOMIC | GFP_DMA); + buffer_info->skb = skb; if (!(buffer_info->skb)) return -ENOMEM; buffer_info->dma_ptr = dma_map_single(&rx->adapter->pdev->dev, @@ -2060,8 +2068,19 @@ static int lan743x_rx_process_packet(struct lan743x_rx *rx) /* packet is available */ if (first_index == last_index) { /* single buffer packet */ + struct sk_buff *new_skb = NULL; int packet_length; + new_skb = lan743x_rx_allocate_skb(rx); + if (!new_skb) { + /* failed to allocate next skb. + * Memory is very low. + * Drop this packet and reuse buffer. + */ + lan743x_rx_reuse_ring_element(rx, first_index); + goto process_extension; + } + buffer_info = &rx->buffer_info[first_index]; skb = buffer_info->skb; descriptor = &rx->ring_cpu_ptr[first_index]; @@ -2081,7 +2100,7 @@ static int lan743x_rx_process_packet(struct lan743x_rx *rx) skb_put(skb, packet_length - 4); skb->protocol = eth_type_trans(skb, rx->adapter->netdev); - lan743x_rx_allocate_ring_element(rx, first_index); + lan743x_rx_init_ring_element(rx, first_index, new_skb); } else { int index = first_index; @@ -2094,26 +2113,23 @@ static int lan743x_rx_process_packet(struct lan743x_rx *rx) if (first_index <= last_index) { while ((index >= first_index) && (index <= last_index)) { - lan743x_rx_release_ring_element(rx, - index); - lan743x_rx_allocate_ring_element(rx, - index); + lan743x_rx_reuse_ring_element(rx, + index); index = lan743x_rx_next_index(rx, index); } } else { while ((index >= first_index) || (index <= last_index)) { - lan743x_rx_release_ring_element(rx, - index); - lan743x_rx_allocate_ring_element(rx, - index); + lan743x_rx_reuse_ring_element(rx, + index); index = lan743x_rx_next_index(rx, index); } } } +process_extension: if (extension_index >= 0) { descriptor = &rx->ring_cpu_ptr[extension_index]; buffer_info = &rx->buffer_info[extension_index]; @@ -2290,7 +2306,9 @@ static int lan743x_rx_ring_init(struct lan743x_rx *rx) rx->last_head = 0; for (index = 0; index < rx->ring_size; index++) { - ret = lan743x_rx_allocate_ring_element(rx, index); + struct sk_buff *new_skb = lan743x_rx_allocate_skb(rx); + + ret = lan743x_rx_init_ring_element(rx, index, new_skb); if (ret) goto cleanup; }