From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756141Ab3FPWXh (ORCPT ); Sun, 16 Jun 2013 18:23:37 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46401 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755777Ab3FPWIz (ORCPT ); Sun, 16 Jun 2013 18:08:55 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Wei Liu" , "Jan Beulich" , "David S. Miller" Date: Sun, 16 Jun 2013 23:01:37 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [21/83] xen-netback: avoid allocating variable size array on stack In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.101 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.47-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Wei Liu commit 59ccb4ebbc35e36a3c143f2d1355deb75c2e628f upstream. Tune xen_netbk_count_requests to not touch working array beyond limit, so that we can make working array size constant. Suggested-by: Jan Beulich Signed-off-by: Wei Liu Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- drivers/net/xen-netback/netback.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -906,11 +906,14 @@ static int netbk_count_requests(struct x RING_IDX cons = vif->tx.req_cons; int slots = 0; int drop_err = 0; + int more_data; if (!(first->flags & XEN_NETTXF_more_data)) return 0; do { + struct xen_netif_tx_request dropped_tx = { 0 }; + if (slots >= work_to_do) { netdev_err(vif->dev, "Asked for %d slots but exceeds this limit\n", @@ -944,6 +947,9 @@ static int netbk_count_requests(struct x drop_err = -E2BIG; } + if (drop_err) + txp = &dropped_tx; + memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots), sizeof(*txp)); @@ -973,7 +979,13 @@ static int netbk_count_requests(struct x netbk_fatal_tx_err(vif); return -EINVAL; } - } while ((txp++)->flags & XEN_NETTXF_more_data); + + more_data = txp->flags & XEN_NETTXF_more_data; + + if (!drop_err) + txp++; + + } while (more_data); if (drop_err) { netbk_tx_err(vif, first, cons + slots); @@ -1385,7 +1397,7 @@ static unsigned xen_netbk_tx_build_gops( !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;