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[84.16.102.26]) by smtp.gmail.com with ESMTPSA id o8sm12013840wma.1.2019.02.25.23.00.15 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 25 Feb 2019 23:00:15 -0800 (PST) Date: Tue, 26 Feb 2019 07:50:25 +0100 From: Jiri Pirko To: Jakub Kicinski Cc: davem@davemloft.net, mkubecek@suse.cz, andrew@lunn.ch, f.fainelli@gmail.com, netdev@vger.kernel.org, oss-drivers@netronome.com Subject: Re: [PATCH net-next v3 5/6] devlink: hold a reference to the netdevice around ethtool compat Message-ID: <20190226065025.GA2338@nanopsycho.orion> References: <20190222220758.7117-1-jakub.kicinski@netronome.com> <20190222220758.7117-6-jakub.kicinski@netronome.com> <20190224110003.GI2759@nanopsycho.orion> <20190225103127.4f17f900@cakuba.netronome.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190225103127.4f17f900@cakuba.netronome.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Mon, Feb 25, 2019 at 07:31:27PM CET, jakub.kicinski@netronome.com wrote: >On Sun, 24 Feb 2019 12:00:03 +0100, Jiri Pirko wrote: >> Fri, Feb 22, 2019 at 11:07:56PM CET, jakub.kicinski@netronome.com wrote: >> >When ethtool is calling into devlink compat code make sure we have >> >a reference on the netdevice on which the operation was invoked. >> > >> >v3: move the hold/lock logic into devlink_compat_* functions (Florian) >> > >> >Signed-off-by: Jakub Kicinski >> >--- >> > net/core/devlink.c | 34 +++++++++++++++++++++++----------- >> > net/core/ethtool.c | 13 ++----------- >> > 2 files changed, 25 insertions(+), 22 deletions(-) >> > >> >diff --git a/net/core/devlink.c b/net/core/devlink.c >> >index a13055160be0..78c6ea1870ca 100644 >> >--- a/net/core/devlink.c >> >+++ b/net/core/devlink.c >> >@@ -6430,27 +6430,39 @@ void devlink_compat_running_version(struct net_device *dev, >> > { >> > struct devlink *devlink; >> > >> >+ dev_hold(dev); >> >+ rtnl_unlock(); >> >> Ha, I got it now. You rely on dev_hold to make sure the >> devlink instance does not dissappear. But until this patch, that is not >> guaranteed (or I'm missing it). > >Yup, I think the expectation that drivers should free netdevs before >unregistering devlink holds today. But it may be a source of bugs :S Sure. > >I can add take devlink_mutex, and check the devlink instance is >registered. Do you prefer an explicit ->registered field like port has, >or can I do this: Yeah, let's add WARN_ON. > >diff --git a/net/core/devlink.c b/net/core/devlink.c >index cefcc0f45d44..be39ad6a4e2e 100644 >--- a/net/core/devlink.c >+++ b/net/core/devlink.c >@@ -5275,6 +5275,7 @@ struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size) > return NULL; > devlink->ops = ops; > devlink_net_set(devlink, &init_net); >+ INIT_LIST_HEAD(&devlink->list); > INIT_LIST_HEAD(&devlink->port_list); > INIT_LIST_HEAD(&devlink->sb_list); > INIT_LIST_HEAD_RCU(&devlink->dpipe_table_list); >@@ -5303,6 +5304,11 @@ int devlink_register(struct devlink *devlink, struct device *dev) > } > EXPORT_SYMBOL_GPL(devlink_register); > >+static bool devlink_is_registered(struct devlink *devlink) >+{ >+ return list_empty(&devlink->list); >+} >+ > /** > * devlink_unregister - Unregister devlink instance > * >@@ -5312,7 +5318,7 @@ void devlink_unregister(struct devlink *devlink) > { > mutex_lock(&devlink_mutex); > devlink_notify(devlink, DEVLINK_CMD_DEL); >- list_del(&devlink->list); >+ list_del_init(&devlink->list); > mutex_unlock(&devlink_mutex); > } > EXPORT_SYMBOL_GPL(devlink_unregister); > >?