Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934724AbdCJJXb (ORCPT ); Fri, 10 Mar 2017 04:23:31 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:38000 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934108AbdCJJX2 (ORCPT ); Fri, 10 Mar 2017 04:23:28 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "K. Y. Srinivasan" Subject: [PATCH 4.9 112/153] Drivers: hv: vmbus: Fix a rescind handling bug Date: Fri, 10 Mar 2017 10:09:05 +0100 Message-Id: <20170310083953.685818360@linuxfoundation.org> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170310083947.108106897@linuxfoundation.org> References: <20170310083947.108106897@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3898 Lines: 136 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: K. Y. Srinivasan commit ccb61f8a99e6c29df4fb96a65dad4fad740d5be9 upstream. The host can rescind a channel that has been offered to the guest and once the channel is rescinded, the host does not respond to any requests on that channel. Deal with the case where the guest may be blocked waiting for a response from the host. Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/channel.c | 18 ++++++++++++++++++ drivers/hv/channel_mgmt.c | 25 +++++++++++++++++++++++++ include/linux/hyperv.h | 1 + 3 files changed, 44 insertions(+) --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -157,6 +157,7 @@ int vmbus_open(struct vmbus_channel *new } init_completion(&open_info->waitevent); + open_info->waiting_channel = newchannel; open_msg = (struct vmbus_channel_open_channel *)open_info->msg; open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL; @@ -194,6 +195,11 @@ int vmbus_open(struct vmbus_channel *new list_del(&open_info->msglistentry); spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + if (newchannel->rescind) { + err = -ENODEV; + goto error_free_gpadl; + } + if (open_info->response.open_result.status) { err = -EAGAIN; goto error_free_gpadl; @@ -405,6 +411,7 @@ int vmbus_establish_gpadl(struct vmbus_c return ret; init_completion(&msginfo->waitevent); + msginfo->waiting_channel = channel; gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg; gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER; @@ -441,6 +448,11 @@ int vmbus_establish_gpadl(struct vmbus_c } wait_for_completion(&msginfo->waitevent); + if (channel->rescind) { + ret = -ENODEV; + goto cleanup; + } + /* At this point, we received the gpadl created msg */ *gpadl_handle = gpadlmsg->gpadl; @@ -474,6 +486,7 @@ int vmbus_teardown_gpadl(struct vmbus_ch return -ENOMEM; init_completion(&info->waitevent); + info->waiting_channel = channel; msg = (struct vmbus_channel_gpadl_teardown *)info->msg; @@ -493,6 +506,11 @@ int vmbus_teardown_gpadl(struct vmbus_ch wait_for_completion(&info->waitevent); + if (channel->rescind) { + ret = -ENODEV; + goto post_msg_err; + } + post_msg_err: spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); list_del(&info->msglistentry); --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -147,6 +147,29 @@ static const struct { { HV_RDV_GUID }, }; +/* + * The rescinded channel may be blocked waiting for a response from the host; + * take care of that. + */ +static void vmbus_rescind_cleanup(struct vmbus_channel *channel) +{ + struct vmbus_channel_msginfo *msginfo; + unsigned long flags; + + + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + + list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list, + msglistentry) { + + if (msginfo->waiting_channel == channel) { + complete(&msginfo->waitevent); + break; + } + } + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); +} + static bool is_unsupported_vmbus_devs(const uuid_le *guid) { int i; @@ -825,6 +848,8 @@ static void vmbus_onoffer_rescind(struct channel->rescind = true; spin_unlock_irqrestore(&channel->lock, flags); + vmbus_rescind_cleanup(channel); + if (channel->device_obj) { if (channel->chn_rescind_callback) { channel->chn_rescind_callback(channel); --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -641,6 +641,7 @@ struct vmbus_channel_msginfo { /* Synchronize the request/response if needed */ struct completion waitevent; + struct vmbus_channel *waiting_channel; union { struct vmbus_channel_version_supported version_supported; struct vmbus_channel_open_result open_result;