From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leon Romanovsky Subject: Re: [PATCH rdma-next V1 1/9] IB/ipoib: Add warning message when changing the MTU in UD over the max range Date: Fri, 13 Jan 2017 17:15:07 +0200 Message-ID: <20170113151507.GR20392@mtr-leonro.local> References: <20161228124728.26619-1-leon@kernel.org> <20161228124728.26619-2-leon@kernel.org> <1484246776.123135.19.camel@redhat.com> <20170112193508.GO20392@mtr-leonro.local> <1484258308.123135.41.camel@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="4dIe/AmYstFUGHTF" Return-path: Content-Disposition: inline In-Reply-To: <1484258308.123135.41.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Doug Ledford Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Feras Daoud , Noa Osherovich List-Id: linux-rdma@vger.kernel.org --4dIe/AmYstFUGHTF Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 12, 2017 at 04:58:28PM -0500, Doug Ledford wrote: > On Thu, 2017-01-12 at 21:35 +0200, Leon Romanovsky wrote: > >=A0 > > First of all, thank you for fixing wording, for me it is the hardest > > part of every commit. > > No worries. > > > Second, I have a different view from you on the issue. User > > configured > > some value, which is not correct for IPoIB. In ideal world (without > > legacy), > > we were supposed to return error to him with proper message, > > If you set an impossible MTU on an ethernet adapter, you get a return > of EINVAL. =A0But it doesn't mess with the kernel log at all, it's *just* > EINVAL to the calling program. > > > but in our > > case (legacy applications) we can't (we tried and it broke some > > legacy > > ifcongfig, if I remember well). > > ifconfig is what I used to test what Ethernet does, so it should be > well and truly used to EINVAL as a return. I'll recheck with Feras next week which legacy tool didn't work and will post it. > > > So it leaves us with one available > > option is to warn user about improper value. > > Even if you want to alert the user, there is no need to warn. =A0Warn is > reserved for something that is a serious error or condition, this is an > EINVAL of something that is, at best, a performance issue. =A0Unless path > MTU support is broken, failing to set a larger MTU will not ever hinder > actual operation. =A0So we should never be dumping out KERN_WARN messages > into the kernel log that will ping up on any root login session as well > as clutter the kernel dmesg output. > > > User should know that he supplied wrong parameter. > > User can still find out, they just won't get proactive pings on all > root sessions, instead they will have to look in the dmesg output > because they are trying to figure out why their command didn't work. > > > > > > > > > > -- > > > Doug Ledford > > > =A0 =A0 GPG KeyID: B826A3330E572FDD > > > =A0 =A0 > > > Key fingerprint =3D AE6B 1BDA 122B 23B4 265B =A01274 B826 A333 0E57 > > > 2FDD > > > > > -- > Doug Ledford > =A0 =A0 GPG KeyID: B826A3330E572FDD > =A0 =A0 > Key fingerprint =3D AE6B 1BDA 122B 23B4 265B =A01274 B826 A333 0E57 2FDD --4dIe/AmYstFUGHTF Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkhr/r4Op1/04yqaB5GN7iDZyWKcFAlh47vsACgkQ5GN7iDZy WKcRGA/+OoOsEIeP6/y74NS9HOBoprD95IaKFpmmdosjLamWIhodUyKRBjBGC95e E1TPv8bBJA4JePIk5uKmVhuLZD0+GfmaFHcB1kK46mswyP/212gj44nNbyPPYo4L HgsjlGBNH8vrlct2df87ozc3jPg/tuvvVemLYerzikDxe5M5eov+ffAeBOhphVX2 8jWK1c95TCIIHR/dGaB8Qm0rjxUTKIRnCAdeSghjLGyfQmkZQxhWY7B0bqb0VJTT fc1dgR0Ou+TljtCdlZlSNGkYpY/hFYTmjUu+sChklHCNt+VtUDRW2sOB1VsodOkP YuOY2jElj2i9aU3cSkFVq/V9wlb433BW4B1FKKS11QhQEoR/h7M+HBD6F7eWN7rh m9OTeYb8N+OZUWAtsrh2nUum8GRyzIDI1dLYHut906xVPh1OxBQ4Xa8Yq8tlshf2 Y5MyBKTQkAl3eOJVA53wj70EWgE6cuFpGxc8o/EvoCIPz/vyVyp8WbpLqfNsO12X van67Jc4GRh4wE+uZrrSNMTZy4dUL9BYqWiOLqKxac7xjzE9Pa+XLHiG0f1cTQ8l +7YpoqWCdCN5hgSBNdYsvqln+uG8zw9W06ZrW02JTMxbaoBmKTAv4BkQZdQ2DKMJ 2xodLDPEUY27bF8i1a8nfVjA+193AqHvLzssNNjmjjW48jKthko= =4/S6 -----END PGP SIGNATURE----- --4dIe/AmYstFUGHTF-- -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html