From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42666C43441 for ; Sun, 11 Nov 2018 19:58:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 10C7F214F1 for ; Sun, 11 Nov 2018 19:58:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 10C7F214F1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730199AbeKLFsM (ORCPT ); Mon, 12 Nov 2018 00:48:12 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:49684 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730055AbeKLFsK (ORCPT ); Mon, 12 Nov 2018 00:48:10 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gLvsW-0000oP-Ca; Sun, 11 Nov 2018 19:58:40 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gLvsT-0001ao-1c; Sun, 11 Nov 2018 19:58:37 +0000 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, "David S. Miller" , "David Vrabel" Date: Sun, 11 Nov 2018 19:49:05 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 164/366] xen-netfront: release per-queue Tx and Rx resource when disconnecting In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.61-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: David Vrabel commit a5b5dc3ce4df4f05f4d81c7d3c56a7604b242093 upstream. Since netfront may reconnect to a backend with a different number of queues, all per-queue Rx and Tx resources (skbs and grant references) should be freed when disconnecting. Without this fix, the Tx and Rx grant refs are not released and netfront will exhaust them after only a few reconnections. netfront will fail to connect when no free grant references are available. Since all Rx bufs are freed and reallocated instead of reused this will add some additional delay to the reconnection but this is expected to be small compared to the time taken by any backend hotplug scripts etc. Signed-off-by: David Vrabel Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- drivers/net/xen-netfront.c | 68 ++++---------------------------------- 1 file changed, 7 insertions(+), 61 deletions(-) --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -1194,22 +1194,6 @@ static void xennet_release_rx_bufs(struc spin_unlock_bh(&queue->rx_lock); } -static void xennet_uninit(struct net_device *dev) -{ - struct netfront_info *np = netdev_priv(dev); - unsigned int num_queues = dev->real_num_tx_queues; - struct netfront_queue *queue; - unsigned int i; - - for (i = 0; i < num_queues; ++i) { - queue = &np->queues[i]; - xennet_release_tx_bufs(queue); - xennet_release_rx_bufs(queue); - gnttab_free_grant_references(queue->gref_tx_head); - gnttab_free_grant_references(queue->gref_rx_head); - } -} - static netdev_features_t xennet_fix_features(struct net_device *dev, netdev_features_t features) { @@ -1311,7 +1295,6 @@ static void xennet_poll_controller(struc static const struct net_device_ops xennet_netdev_ops = { .ndo_open = xennet_open, - .ndo_uninit = xennet_uninit, .ndo_stop = xennet_close, .ndo_start_xmit = xennet_start_xmit, .ndo_change_mtu = xennet_change_mtu, @@ -1454,6 +1437,11 @@ static void xennet_disconnect_backend(st if (netif_running(info->netdev)) napi_synchronize(&queue->napi); + xennet_release_tx_bufs(queue); + xennet_release_rx_bufs(queue); + gnttab_free_grant_references(queue->gref_tx_head); + gnttab_free_grant_references(queue->gref_rx_head); + /* End access and free the pages */ xennet_end_access(queue->tx_ring_ref, queue->tx.sring); xennet_end_access(queue->rx_ring_ref, queue->rx.sring); @@ -2009,10 +1997,7 @@ static int xennet_connect(struct net_dev { struct netfront_info *np = netdev_priv(dev); unsigned int num_queues = 0; - int i, requeue_idx, err; - struct sk_buff *skb; - grant_ref_t ref; - struct xen_netif_rx_request *req; + int err; unsigned int feature_rx_copy; unsigned int j = 0; struct netfront_queue *queue = NULL; @@ -2039,47 +2024,8 @@ static int xennet_connect(struct net_dev netdev_update_features(dev); rtnl_unlock(); - /* By now, the queue structures have been set up */ - for (j = 0; j < num_queues; ++j) { - queue = &np->queues[j]; - - /* Step 1: Discard all pending TX packet fragments. */ - spin_lock_irq(&queue->tx_lock); - xennet_release_tx_bufs(queue); - spin_unlock_irq(&queue->tx_lock); - - /* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */ - spin_lock_bh(&queue->rx_lock); - - for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) { - skb_frag_t *frag; - const struct page *page; - if (!queue->rx_skbs[i]) - continue; - - skb = queue->rx_skbs[requeue_idx] = xennet_get_rx_skb(queue, i); - ref = queue->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(queue, i); - req = RING_GET_REQUEST(&queue->rx, requeue_idx); - - frag = &skb_shinfo(skb)->frags[0]; - page = skb_frag_page(frag); - gnttab_grant_foreign_access_ref( - ref, queue->info->xbdev->otherend_id, - pfn_to_mfn(page_to_pfn(page)), - 0); - req->gref = ref; - req->id = requeue_idx; - - requeue_idx++; - } - - queue->rx.req_prod_pvt = requeue_idx; - - spin_unlock_bh(&queue->rx_lock); - } - /* - * Step 3: All public and private state should now be sane. Get + * All public and private state should now be sane. Get * ready to start sending and receiving packets and give the driver * domain a kick because we've probably just requeued some * packets.