Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756267AbbGPRxF (ORCPT ); Thu, 16 Jul 2015 13:53:05 -0400 Received: from p3plsmtps2ded03.prod.phx3.secureserver.net ([208.109.80.60]:59826 "EHLO p3plsmtps2ded03.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753375AbbGPRxD (ORCPT ); Thu, 16 Jul 2015 13:53:03 -0400 x-originating-ip: 72.167.245.219 From: "K. Y. Srinivasan" To: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, jasowang@redhat.com, vkuznets@redhat.com, decui@microsoft.com Cc: "K. Y. Srinivasan" Subject: [PATCH net-next 1/1] hv_netvsc: Wait for sub-channels to be processed during probe Date: Thu, 16 Jul 2015 12:17:02 -0700 Message-Id: <1437074222-13020-1-git-send-email-kys@microsoft.com> X-Mailer: git-send-email 1.7.4.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3723 Lines: 109 The current code returns from probe without waiting for the proper handling of subchannels that may be requested. If the netvsc driver were to be rapidly loaded/unloaded, we can trigger a panic as the unload will be tearing down state that may not have been fully setup yet. We fix this issue by making sure that we return from the probe call only after ensuring that the sub-channel offers in flight are properly handled. Signed-off-by: K. Y. Srinivasan Reviewed-and-tested-by: Haiyang Zhang offermsg.offer.sub_channel_index; int ret; + unsigned long flags; nvscdev = hv_get_drvdata(new_sc->primary_channel->device_obj); + spin_lock_irqsave(&nvscdev->sc_lock, flags); + nvscdev->num_sc_offered--; + spin_unlock_irqrestore(&nvscdev->sc_lock, flags); + if (nvscdev->num_sc_offered == 0) + complete(&nvscdev->channel_init_wait); + if (chn_index >= nvscdev->num_chn) return; @@ -1015,8 +1022,10 @@ int rndis_filter_device_add(struct hv_device *dev, u32 rsscap_size = sizeof(struct ndis_recv_scale_cap); u32 mtu, size; u32 num_rss_qs; + u32 sc_delta; const struct cpumask *node_cpu_mask; u32 num_possible_rss_qs; + unsigned long flags; rndis_device = get_rndis_device(); if (!rndis_device) @@ -1039,6 +1048,8 @@ int rndis_filter_device_add(struct hv_device *dev, net_device->max_chn = 1; net_device->num_chn = 1; + spin_lock_init(&net_device->sc_lock); + net_device->extension = rndis_device; rndis_device->net_dev = net_device; @@ -1116,6 +1127,9 @@ int rndis_filter_device_add(struct hv_device *dev, num_possible_rss_qs = cpumask_weight(node_cpu_mask); net_device->num_chn = min(num_possible_rss_qs, num_rss_qs); + num_rss_qs = net_device->num_chn - 1; + net_device->num_sc_offered = num_rss_qs; + if (net_device->num_chn == 1) goto out; @@ -1157,11 +1171,22 @@ int rndis_filter_device_add(struct hv_device *dev, ret = rndis_filter_set_rss_param(rndis_device, net_device->num_chn); + /* + * Wait for the host to send us the sub-channel offers. + */ + spin_lock_irqsave(&net_device->sc_lock, flags); + sc_delta = net_device->num_chn - 1 - num_rss_qs; + net_device->num_sc_offered -= sc_delta; + spin_unlock_irqrestore(&net_device->sc_lock, flags); + + if (net_device->num_sc_offered != 0) + wait_for_completion(&net_device->channel_init_wait); out: if (ret) { net_device->max_chn = 1; net_device->num_chn = 1; } + return 0; /* return 0 because primary channel can be used alone */ err_dev_remv: -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/