From patchwork Tue Apr 30 16:50:44 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Liu X-Patchwork-Id: 240666 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 6275C2C00CC for ; Wed, 1 May 2013 02:54:20 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761263Ab3D3QyR (ORCPT ); Tue, 30 Apr 2013 12:54:17 -0400 Received: from smtp.citrix.com ([66.165.176.89]:16193 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760830Ab3D3QyQ (ORCPT ); Tue, 30 Apr 2013 12:54:16 -0400 X-IronPort-AV: E=Sophos;i="4.87,582,1363132800"; d="scan'208";a="22435167" Received: from accessns.citrite.net (HELO FTLPEX01CL03.citrite.net) ([10.9.154.239]) by FTLPIPO01.CITRIX.COM with ESMTP/TLS/AES128-SHA; 30 Apr 2013 16:54:14 +0000 Received: from ukmail1.uk.xensource.com (10.80.16.128) by smtprelay.citrix.com (10.13.107.80) with Microsoft SMTP Server id 14.2.342.3; Tue, 30 Apr 2013 12:54:13 -0400 Received: from dt47.uk.xensource.com ([10.80.229.47] helo=dt47.uk.xensource.com.) by ukmail1.uk.xensource.com with esmtp (Exim 4.69) (envelope-from ) id 1UXDlN-0004LK-LZ; Tue, 30 Apr 2013 17:50:45 +0100 From: Wei Liu To: , CC: , , Wei Liu Subject: [PATCH net-next 2/2] xen-netback: avoid allocating variable size array on stack Date: Tue, 30 Apr 2013 17:50:44 +0100 Message-ID: <1367340644-19690-3-git-send-email-wei.liu2@citrix.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1367340644-19690-1-git-send-email-wei.liu2@citrix.com> References: <1367340644-19690-1-git-send-email-wei.liu2@citrix.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Tune xen_netbk_count_requests to not touch working array beyond limit, so that we can make working array size constant. Signed-off-by: Wei Liu --- drivers/net/xen-netback/netback.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index c44772d..c6dc084 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -934,11 +934,15 @@ static int netbk_count_requests(struct xenvif *vif, RING_IDX cons = vif->tx.req_cons; int slots = 0; int drop_err = 0; + int keep_looping; if (!(first->flags & XEN_NETTXF_more_data)) return 0; do { + struct xen_netif_tx_request dropped_tx = { 0 }; + int cross_page = 0; + if (slots >= work_to_do) { netdev_err(vif->dev, "Asked for %d slots but exceeds this limit\n", @@ -972,8 +976,12 @@ static int netbk_count_requests(struct xenvif *vif, drop_err = -E2BIG; } - memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots), - sizeof(*txp)); + if (!drop_err) + memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots), + sizeof(*txp)); + else + memcpy(&dropped_tx, RING_GET_REQUEST(&vif->tx, cons + slots), + sizeof(dropped_tx)); /* If the guest submitted a frame >= 64 KiB then * first->size overflowed and following slots will @@ -995,13 +1003,21 @@ static int netbk_count_requests(struct xenvif *vif, first->size -= txp->size; slots++; - if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) { + if (!drop_err) + cross_page = (txp->offset + txp->size) > PAGE_SIZE; + else + cross_page = (dropped_tx.offset + dropped_tx.size) > PAGE_SIZE; + + if (unlikely(cross_page)) { netdev_err(vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n", txp->offset, txp->size); netbk_fatal_tx_err(vif); return -EINVAL; } - } while ((txp++)->flags & XEN_NETTXF_more_data); + + keep_looping = (!drop_err && (txp++)->flags & XEN_NETTXF_more_data) || + (dropped_tx.flags & XEN_NETTXF_more_data); + } while (keep_looping); if (drop_err) { netbk_tx_err(vif, first, cons + slots); @@ -1408,7 +1424,7 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk) !list_empty(&netbk->net_schedule_list)) { struct xenvif *vif; struct xen_netif_tx_request txreq; - struct xen_netif_tx_request txfrags[max_skb_slots]; + struct xen_netif_tx_request txfrags[XEN_NETIF_NR_SLOTS_MIN]; struct page *page; struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1]; u16 pending_idx;