From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [PATCH v3 3/3] IB/ipoib: Log sysfs 'dev_id' accesses from userspace Date: Fri, 07 Sep 2018 13:14:37 -0400 Message-ID: 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-sha256"; protocol="application/pgp-signature"; boundary="=-y6OJqvcUuG7NIyNJ1dEl" Cc: linux-rdma@vger.kernel.org, Jason Gunthorpe , netdev@vger.kernel.org To: Leon Romanovsky , Arseny Maslennikov Return-path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:34202 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727175AbeIGV4e (ORCPT ); Fri, 7 Sep 2018 17:56:34 -0400 In-Reply-To: <20180906130358.GJ3142@mtr-leonro.mtl.com> Sender: netdev-owner@vger.kernel.org List-ID: --=-y6OJqvcUuG7NIyNJ1dEl Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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(+) > > > >=20 > > > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/in= finiband/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 *d= ev) > > > > return device_create_file(&dev->dev, &dev_attr_pkey); > > > > } > > > >=20 > > > > +/* > > > > + * We erroneously exposed the iface's port number in the dev_id > > > > + * sysfs field long after dev_port was introduced for that purpose= [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); > > > > + > > >=20 > > > I don't see this field among exposed by IPoIB, why should we expose i= t now? > > >=20 > >=20 > > 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. > >=20 > > > > +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); > > >=20 > > > Why isn't enough to rely on netdev code? > > >=20 > >=20 > > 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 heade= r > > 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. > >=20 > > 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 bu= t we have > > no access to it. > >=20 > > Of course, it also may be that I'm terribly missing a clue. >=20 > Thanks, >=20 > IMHO, the end result of adequate Doug's request is a little bit too much. > I don't think that it justifies such remove->create construction. >=20 > 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. --=20 Doug Ledford GPG KeyID: B826A3330E572FDD Key fingerprint =3D AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD --=-y6OJqvcUuG7NIyNJ1dEl Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEErmsb2hIrI7QmWxJ0uCajMw5XL90FAluSsf0ACgkQuCajMw5X L90Sfw/9GoyRCCCCuhDVX4jb/V+tZzSPKpGJrfbTTTaQliLfmbY2JjYwLr15Ok9H aOoXEPmV7+FIX5ifeSWTn6Nxn9p//71J/Vfc1fxgQwCIlstCET/AfgmDOmsdmcIm iI6EuRi7+EmBh6WJwHWo2cogPCEIcP85XtGOIj2JujIcVJd88P+5+k0hR1FVb/ef m7tCr2uHspUM6Xcd9Z9KCE+fHZP3W2pBYV+6N06XSrAAUebn1wnTPx21wgyemKRW 9cVwMPcvkSyhYUHfj46WE0pTMKEK+JR03QOqZBMqgz1D4FGecU0JU7vKrhvm2fi+ VwBCFVnHTV4uwNWBW4bMhP/9prEkvAyRVEbTyN0YjJLu+rEvXx04aBxR7IwRBqsa IML//2/KI1r880H9wSiaBOnhRbnoHqbQUHmUfyV8zy0LUOuQxyBaz68LT94PaxPd 83BKywrnUCeNCbYWFYnLatNcbxQ0GbaXaE9shewK5Lsk3LnJNv0OtqgdFkW/30sj FYUo1MAuawLdd7WTHQob8EXuCdkS5ZNycJe49Bnm49gjunp6RlurlTiiOeKUpziO bYK27Yb1g9QmZMY5iJQPQc592fPcp6lF0jffKzCXOfDhzzofPJk2mgNjb35HTG7I W3IwlDutVo+M6fO1+Wd/tcaagbb+eDdGcOpFJTkqG8cx5LjLUOs= =4+m2 -----END PGP SIGNATURE----- --=-y6OJqvcUuG7NIyNJ1dEl--