From mboxrd@z Thu Jan 1 00:00:00 1970 From: Abdul Haleem Subject: Re: [PATCH net] net/ibmnvic: Fix deadlock problem in reset Date: Wed, 21 Nov 2018 16:10:41 +0530 Message-ID: <1542796841.15177.14.camel@abdul> References: <20181119215727.22197.97260.stgit@ltcalpine2-lp22.aus.stglabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, mwb@linux.vnet.ibm.com, tlfalcon@linux.vnet.ibm.com, tyreld@linux.vnet.ibm.com To: Juliet Kim Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:55346 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726849AbeKUVOo (ORCPT ); Wed, 21 Nov 2018 16:14:44 -0500 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wALAdjvJ045329 for ; Wed, 21 Nov 2018 05:40:50 -0500 Received: from e12.ny.us.ibm.com (e12.ny.us.ibm.com [129.33.205.202]) by mx0a-001b2d01.pphosted.com with ESMTP id 2nw59jsrn2-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 21 Nov 2018 05:40:50 -0500 Received: from localhost by e12.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 21 Nov 2018 10:40:49 -0000 In-Reply-To: <20181119215727.22197.97260.stgit@ltcalpine2-lp22.aus.stglabs.ibm.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2018-11-19 at 15:59 -0600, Juliet Kim wrote: > This patch changes to use rtnl_lock only during a reset to avoid > deadlock that could occur when a thread operating close is holding > rtnl_lock and waiting for reset_lock acquired by another thread, > which is waiting for rtnl_lock in order to set the number of tx/rx > queues during a reset. > > Also, we now setting the number of tx/rx queues during a soft reset > for failover or LPM events. > > Signed-off-by: Juliet Kim > --- > drivers/net/ethernet/ibm/ibmvnic.c | 59 +++++++++++++----------------------- > drivers/net/ethernet/ibm/ibmvnic.h | 2 + > 2 files changed, 22 insertions(+), 39 deletions(-) > > diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c > index 7893bef..4a5de59 100644 > --- a/drivers/net/ethernet/ibm/ibmvnic.c > +++ b/drivers/net/ethernet/ibm/ibmvnic.c > @@ -1103,20 +1103,15 @@ static int ibmvnic_open(struct net_device *netdev) > return 0; > } > > - mutex_lock(&adapter->reset_lock); > - > if (adapter->state != VNIC_CLOSED) { > rc = ibmvnic_login(netdev); > - if (rc) { > - mutex_unlock(&adapter->reset_lock); > + if (rc) > return rc; > - } > > rc = init_resources(adapter); > if (rc) { > netdev_err(netdev, "failed to initialize resources\n"); > release_resources(adapter); > - mutex_unlock(&adapter->reset_lock); > return rc; > } > } > @@ -1124,8 +1119,6 @@ static int ibmvnic_open(struct net_device *netdev) > rc = __ibmvnic_open(netdev); > netif_carrier_on(netdev); > > - mutex_unlock(&adapter->reset_lock); > - > return rc; > } > > @@ -1269,10 +1262,8 @@ static int ibmvnic_close(struct net_device *netdev) > return 0; > } > > - mutex_lock(&adapter->reset_lock); > rc = __ibmvnic_close(netdev); > ibmvnic_cleanup(netdev); > - mutex_unlock(&adapter->reset_lock); > > return rc; > } > @@ -1820,20 +1811,15 @@ static int do_reset(struct ibmvnic_adapter *adapter, > return rc; > } else if (adapter->req_rx_queues != old_num_rx_queues || > adapter->req_tx_queues != old_num_tx_queues) { > - adapter->map_id = 1; > release_rx_pools(adapter); > release_tx_pools(adapter); > - rc = init_rx_pools(netdev); > - if (rc) > - return rc; > - rc = init_tx_pools(netdev); > - if (rc) > - return rc; > - > release_napi(adapter); > - rc = init_napi(adapter); > + release_vpd_data(adapter); > + > + rc = init_resources(adapter); > if (rc) > return rc; > + > } else { > rc = reset_tx_pools(adapter); > if (rc) > @@ -1917,17 +1903,8 @@ static int do_hard_reset(struct ibmvnic_adapter *adapter, > adapter->state = VNIC_PROBED; > return 0; > } > - /* netif_set_real_num_xx_queues needs to take rtnl lock here > - * unless wait_for_reset is set, in which case the rtnl lock > - * has already been taken before initializing the reset > - */ > - if (!adapter->wait_for_reset) { > - rtnl_lock(); > - rc = init_resources(adapter); > - rtnl_unlock(); > - } else { > - rc = init_resources(adapter); > - } > + > + rc = init_resources(adapter); > if (rc) > return rc; > > @@ -1986,13 +1963,21 @@ static void __ibmvnic_reset(struct work_struct *work) > struct ibmvnic_rwi *rwi; > struct ibmvnic_adapter *adapter; > struct net_device *netdev; > + bool we_lock_rtnl = false; > u32 reset_state; > int rc = 0; > > adapter = container_of(work, struct ibmvnic_adapter, ibmvnic_reset); > netdev = adapter->netdev; > > - mutex_lock(&adapter->reset_lock); > + /* netif_set_real_num_xx_queues needs to take rtnl lock here > + * unless wait_for_reset is set, in which case the rtnl lock > + * has already been taken before initializing the reset > + */ > + if (!adapter->wait_for_reset) { > + rtnl_lock(); > + we_lock_rtnl = true; > + } > reset_state = adapter->state; > > rwi = get_next_rwi(adapter); > @@ -2020,12 +2005,11 @@ static void __ibmvnic_reset(struct work_struct *work) > if (rc) { > netdev_dbg(adapter->netdev, "Reset failed\n"); > free_all_rwi(adapter); > - mutex_unlock(&adapter->reset_lock); > - return; > } > > adapter->resetting = false; > - mutex_unlock(&adapter->reset_lock); > + if (we_lock_rtnl) > + rtnl_unlock(); > } > > static int ibmvnic_reset(struct ibmvnic_adapter *adapter, > @@ -4768,7 +4752,6 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id) > > INIT_WORK(&adapter->ibmvnic_reset, __ibmvnic_reset); > INIT_LIST_HEAD(&adapter->rwi_list); > - mutex_init(&adapter->reset_lock); > mutex_init(&adapter->rwi_lock); > adapter->resetting = false; > > @@ -4840,8 +4823,8 @@ static int ibmvnic_remove(struct vio_dev *dev) > struct ibmvnic_adapter *adapter = netdev_priv(netdev); > > adapter->state = VNIC_REMOVING; > - unregister_netdev(netdev); > - mutex_lock(&adapter->reset_lock); > + rtnl_lock(); > + unregister_netdevice(netdev); > > release_resources(adapter); > release_sub_crqs(adapter, 1); > @@ -4852,7 +4835,7 @@ static int ibmvnic_remove(struct vio_dev *dev) > > adapter->state = VNIC_REMOVED; > > - mutex_unlock(&adapter->reset_lock); > + rtnl_unlock(); > device_remove_file(&dev->dev, &dev_attr_failover); > free_netdev(netdev); > dev_set_drvdata(&dev->dev, NULL); > diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h > index 18103b8..99c4f8d 100644 > --- a/drivers/net/ethernet/ibm/ibmvnic.h > +++ b/drivers/net/ethernet/ibm/ibmvnic.h > @@ -1075,7 +1075,7 @@ struct ibmvnic_adapter { > struct tasklet_struct tasklet; > enum vnic_state state; > enum ibmvnic_reset_reason reset_reason; > - struct mutex reset_lock, rwi_lock; > + struct mutex rwi_lock; > struct list_head rwi_list; > struct work_struct ibmvnic_reset; > bool resetting; > Thanks for the fix, Please add Reported-and-tested-by: Abdul Haleem -- Regard's Abdul Haleem IBM Linux Technology Centre