From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leon Romanovsky Subject: Re: [PATCH v3 3/3] IB/ipoib: Log sysfs 'dev_id' accesses from userspace Date: Fri, 7 Sep 2018 20:28:21 +0300 Message-ID: <20180907172821.GS3142@mtr-leonro.mtl.com> References: <20180903161316.25121-1-ar@cs.msu.ru> <20180903161316.25121-4-ar@cs.msu.ru> <20180905135035.GT2977@mtr-leonro.mtl.com> <20180906070433.GA13034@cello> <20180906130358.GJ3142@mtr-leonro.mtl.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="d6iqOn7HZPWKXx18" Return-path: Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org To: Doug Ledford Cc: Arseny Maslennikov , linux-rdma@vger.kernel.org, Jason Gunthorpe , netdev@vger.kernel.org List-Id: linux-rdma@vger.kernel.org --d6iqOn7HZPWKXx18 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Sep 07, 2018 at 01:14:37PM -0400, Doug Ledford wrote: > On Thu, 2018-09-06 at 16:03 +0300, Leon Romanovsky wrote: > > On Thu, Sep 06, 2018 at 10:04:33AM +0300, Arseny Maslennikov wrote: > > > On Wed, Sep 05, 2018 at 04:50:35PM +0300, Leon Romanovsky wrote: > > > > On Mon, Sep 03, 2018 at 07:13:16PM +0300, Arseny Maslennikov wrote: > > > > > Signed-off-by: Arseny Maslennikov > > > > > --- > > > > > drivers/infiniband/ulp/ipoib/ipoib_main.c | 38 +++++++++++++++++= ++++++ > > > > > 1 file changed, 38 insertions(+) > > > > > > > > > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/= infiniband/ulp/ipoib/ipoib_main.c > > > > > index 30f840f874b3..7386e5bde3d3 100644 > > > > > --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c > > > > > +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c > > > > > @@ -2386,6 +2386,42 @@ int ipoib_add_pkey_attr(struct net_device = *dev) > > > > > return device_create_file(&dev->dev, &dev_attr_pkey); > > > > > } > > > > > > > > > > +/* > > > > > + * We erroneously exposed the iface's port number in the dev_id > > > > > + * sysfs field long after dev_port was introduced for that purpo= se[1], > > > > > + * and we need to stop everyone from relying on that. > > > > > + * Let's overload the shower routine for the dev_id file here > > > > > + * to gently bring the issue up. > > > > > + * > > > > > + * [1] https://www.spinics.net/lists/netdev/msg272123.html > > > > > + */ > > > > > +static ssize_t dev_id_show(struct device *dev, > > > > > + struct device_attribute *attr, char *buf) > > > > > +{ > > > > > + struct net_device *ndev =3D to_net_dev(dev); > > > > > + ssize_t ret =3D -EINVAL; > > > > > + > > > > > + if (ndev->dev_id =3D=3D ndev->dev_port) { > > > > > + netdev_info_once(ndev, > > > > > + "\"%s\" wants to know my dev_id. " > > > > > + "Should it look at dev_port instead?\n", > > > > > + current->comm); > > > > > + netdev_info_once(ndev, > > > > > + "See Documentation/ABI/testing/sysfs-class-net for more info.= \n"); > > > > > + } > > > > > + > > > > > + ret =3D sprintf(buf, "%#x\n", ndev->dev_id); > > > > > + > > > > > + return ret; > > > > > +} > > > > > +static DEVICE_ATTR_RO(dev_id); > > > > > + > > > > > > > > I don't see this field among exposed by IPoIB, why should we expose= it now? > > > > > > > > > > To deviate from standard netdev behaviour, which only prints the > > > field out. Doug wanted this to also print a deprecation message, and > > > netdev (obviously) does not do that. See below. > > > > > > > > +int ipoib_intercept_dev_id_attr(struct net_device *dev) > > > > > +{ > > > > > + device_remove_file(&dev->dev, &dev_attr_dev_id); > > > > > + return device_create_file(&dev->dev, &dev_attr_dev_id); > > > > > > > > Why isn't enough to rely on netdev code? > > > > > > > > > > Netdev code relies on macros around a *static* function 'netdev_show', > > > which is defined in net/core/net-sysfs.c; it is not listed in any hea= der > > > files, and the macros aren't as well. This all leads me to believe it > > > was not really meant to be used from outside net/core/net-sysfs. > > > > > > The only way we could use any netdev code here is to set up our own > > > handler (again), printk() a message, then call netdev_show =E2=80=94 = but we have > > > no access to it. > > > > > > Of course, it also may be that I'm terribly missing a clue. > > > > Thanks, > > > > IMHO, the end result of adequate Doug's request is a little bit too muc= h. > > I don't think that it justifies such remove->create construction. > > > > Personal opinion. > > I agree with you that the end result is kinda bulky, *but*, we will need > to know if there are things using the old dev_id before we can remove > it. In particular, I'm concerned the IPoIB handling code of > NetworkManager uses it. It's worth the cost I think. I did my checks now and saw that ibdev2netdev uses the value provided =66rom this dev_id, so every invocation of that script will generate the warning. See this line in Parav's repo https://github.com/Mellanox/container_scripts/blob/master/ibdev2netdev#L112 Thanks > > -- > Doug Ledford > GPG KeyID: B826A3330E572FDD > Key fingerprint =3D AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD --d6iqOn7HZPWKXx18 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIcBAEBAgAGBQJbkrU1AAoJEORje4g2clin7RAP/3zMXXy4bASkyRm3mBz9tsxl VOSbUHZJ8vp3DVXDFwokrz/D5rGVSvJsS8v0RhQjdGi0wIr2zQuRTbVIFjsoxU41 oi7gybwaQbNb6cT4GKdquKPOf09kLJNDCvSX90dS81LxxNGKi4mugjo1YYTb5qvU HcAt3bFV5emFBCke9Fb33lo3yOWOaUsq26ObVKvsCcGAHjpxf/4B+BKgxkUH/47A EBuqSWEayE4ScHF1TduPtmmvuxpeGC0qPS8MLaJa99t0rIWSd+Cnh+kn2+NruGxv YITJTN1wUX8DRlBjyXfn9SEN7DPZlgY8EX0oSmUJlFj4J+R1P22s8GAeZUMp8Vji 4s2kphCKlOwHCwsNvyHAt/DRl+qOM+hVUVcZoOPCMFLfKSEOjaHBUuDxWe0yVFe3 tnxcFqWBoDdvpfnO2L/dDSIYxVVHBGxkytxjuXgWARx5ZWS9Fc1CK59r4KlJuCwX AgZFD9rT4oIkiQ0IYyoRGclBCSvJs9mysEFoRpYerlJ3tSW1dTSaPr2jcqqeHs+8 yp+LEX8wHkjnfIRubcDPvt1JSB5V7zO01OXVeJ/F4wGeYXfBuQaL4MoMczpNeMAj lWwvFuXgqlnHJcq0xNbrW+JKiZFZ/ukp9+B06lWip08bYiR2apGaabMlLhFhDrfB iUIRge4lIFu98sw799ln =YFZf -----END PGP SIGNATURE----- --d6iqOn7HZPWKXx18--