From a5b5dc3ce4df4f05f4d81c7d3c56a7604b242093 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Thu, 31 Jul 2014 17:38:23 +0100 Subject: [PATCH] xen-netfront: release per-queue Tx and Rx resource when disconnecting 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 --- drivers/net/xen-netfront.c | 68 ++++---------------------------------- 1 file changed, 7 insertions(+), 61 deletions(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 1cc46d00d20a..0b133a3d4312 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -1196,22 +1196,6 @@ static void xennet_release_rx_bufs(struct netfront_queue *queue) 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) { @@ -1313,7 +1297,6 @@ static void xennet_poll_controller(struct net_device *dev) 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, @@ -1455,6 +1438,11 @@ static void xennet_disconnect_backend(struct netfront_info *info) 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); @@ -2010,10 +1998,7 @@ static int xennet_connect(struct net_device *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; @@ -2040,47 +2025,8 @@ static int xennet_connect(struct net_device *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.