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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 38EBEC47082 for ; Mon, 7 Jun 2021 11:23:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C0C5610A8 for ; Mon, 7 Jun 2021 11:23:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230479AbhFGLZ2 (ORCPT ); Mon, 7 Jun 2021 07:25:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:40634 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230219AbhFGLZ2 (ORCPT ); Mon, 7 Jun 2021 07:25:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3216F6101A; Mon, 7 Jun 2021 11:23:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623065017; bh=O7XZLfWcHIDDInHsO2+3DukI+BQdDd5GqejCej2lk1w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sIay0Q6tSPjyvN2FN3EfwC8tCaJ1izl3Epv0FobJFi0EcvGwOebxfY1HTY/ohveqp 93Yx6a2aymyTYyurKJL/irJw5rWaReTxAc9z4d/MhVvCeotkEjEvQxTgGBhp0KFlXD byCDlpdopzPpC6UYD8NB9qex3YxCBZt3vBjuhOWY= Date: Mon, 7 Jun 2021 13:23:35 +0200 From: Greg KH To: Leon Romanovsky Cc: Doug Ledford , Jason Gunthorpe , Kees Cook , Nathan Chancellor , Adit Ranadive , Ariel Elior , Christian Benvenuti , clang-built-linux@googlegroups.com, Dennis Dalessandro , Devesh Sharma , Gal Pressman , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, Michal Kalderon , Mike Marciniszyn , Mustafa Ismail , Naresh Kumar PBS , Nelson Escobar , Nick Desaulniers , Potnuri Bharat Teja , Selvin Xavier , Shiraz Saleem , VMware PV-Drivers , Yishai Hadas , Zhu Yanjun Subject: Re: [PATCH rdma-next v1 02/15] RDMA/core: Replace the ib_port_data hw_stats pointers with a ib_port pointer Message-ID: References: <6477a29059b1b4d92ea003e3b801a8d1df6d516d.1623053078.git.leonro@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Mon, Jun 07, 2021 at 02:00:26PM +0300, Leon Romanovsky wrote: > On Mon, Jun 07, 2021 at 12:23:23PM +0200, Greg KH wrote: > > On Mon, Jun 07, 2021 at 11:17:27AM +0300, Leon Romanovsky wrote: > > > From: Jason Gunthorpe > > > > > > It is much saner to store a pointer to the kobject structure that contains > > > the cannonical stats pointer than to copy the stats pointers into a public > > > structure. > > > > > > Future patches will require the sysfs pointer for other purposes. > > > > > > Signed-off-by: Jason Gunthorpe > > > Signed-off-by: Leon Romanovsky > > > --- > > > drivers/infiniband/core/core_priv.h | 1 + > > > drivers/infiniband/core/nldev.c | 8 ++------ > > > drivers/infiniband/core/sysfs.c | 14 +++++++++++--- > > > include/rdma/ib_verbs.h | 3 ++- > > > 4 files changed, 16 insertions(+), 10 deletions(-) > > > > > > diff --git a/drivers/infiniband/core/core_priv.h b/drivers/infiniband/core/core_priv.h > > > index 29809dd30041..ec5c2c3db423 100644 > > > --- a/drivers/infiniband/core/core_priv.h > > > +++ b/drivers/infiniband/core/core_priv.h > > > @@ -378,6 +378,7 @@ struct net_device *rdma_read_gid_attr_ndev_rcu(const struct ib_gid_attr *attr); > > > > > > void ib_free_port_attrs(struct ib_core_device *coredev); > > > int ib_setup_port_attrs(struct ib_core_device *coredev); > > > +struct rdma_hw_stats *ib_get_hw_stats_port(struct ib_device *ibdev, u32 port_num); > > > > > > int rdma_compatdev_set(u8 enable); > > > > > > diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c > > > index 01316926cef6..e9b4b2cccaa0 100644 > > > --- a/drivers/infiniband/core/nldev.c > > > +++ b/drivers/infiniband/core/nldev.c > > > @@ -2066,7 +2066,8 @@ static int stat_get_doit_default_counter(struct sk_buff *skb, > > > } > > > > > > port = nla_get_u32(tb[RDMA_NLDEV_ATTR_PORT_INDEX]); > > > - if (!rdma_is_port_valid(device, port)) { > > > + stats = ib_get_hw_stats_port(device, port); > > > + if (!stats) { > > > ret = -EINVAL; > > > goto err; > > > } > > > @@ -2088,11 +2089,6 @@ static int stat_get_doit_default_counter(struct sk_buff *skb, > > > goto err_msg; > > > } > > > > > > - stats = device->port_data ? device->port_data[port].hw_stats : NULL; > > > - if (stats == NULL) { > > > - ret = -EINVAL; > > > - goto err_msg; > > > - } > > > mutex_lock(&stats->lock); > > > > > > num_cnts = device->ops.get_hw_stats(device, stats, port, 0); > > > diff --git a/drivers/infiniband/core/sysfs.c b/drivers/infiniband/core/sysfs.c > > > index d11ceff2b4e4..b153dee1e0fa 100644 > > > --- a/drivers/infiniband/core/sysfs.c > > > +++ b/drivers/infiniband/core/sysfs.c > > > @@ -1031,8 +1031,6 @@ static void setup_hw_stats(struct ib_device *device, struct ib_port *port, > > > goto err; > > > port->hw_stats_ag = hsag; > > > port->hw_stats = stats; > > > - if (device->port_data) > > > - device->port_data[port_num].hw_stats = stats; > > > } else { > > > struct kobject *kobj = &device->dev.kobj; > > > ret = sysfs_create_group(kobj, hsag); > > > @@ -1053,6 +1051,14 @@ static void setup_hw_stats(struct ib_device *device, struct ib_port *port, > > > kfree(stats); > > > } > > > > > > +struct rdma_hw_stats *ib_get_hw_stats_port(struct ib_device *ibdev, > > > + u32 port_num) > > > +{ > > > + if (!ibdev->port_data || !rdma_is_port_valid(ibdev, port_num)) > > > + return NULL; > > > + return ibdev->port_data[port_num].sysfs->hw_stats; > > > +} > > > + > > > static int add_port(struct ib_core_device *coredev, int port_num) > > > { > > > struct ib_device *device = rdma_device_to_ibdev(&coredev->dev); > > > @@ -1171,6 +1177,8 @@ static int add_port(struct ib_core_device *coredev, int port_num) > > > setup_hw_stats(device, p, port_num); > > > > > > list_add_tail(&p->kobj.entry, &coredev->port_list); > > > + if (device->port_data && is_full_dev) > > > + device->port_data[port_num].sysfs = p; > > > > You are saving off a pointer to a reference counted structure without > > incrementing the reference count on it? That's brave, and really wrong. > > This is done to ensure that device->port_data[port_num].sysfs is not set > before "p" is properly configured. From reference point of view "sysfs" > is equal to "p" and the latter already initialized. That's fine, but again, you are saving a pointer to a reference counted object, and then later using it, without ever having properly incremented the reference count to assure that it really is going to stick around. thanks, greg k-h