From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [PATCH rdma-next V1 1/9] IB/ipoib: Add warning message when changing the MTU in UD over the max range Date: Thu, 12 Jan 2017 16:58:28 -0500 Message-ID: <1484258308.123135.41.camel@redhat.com> References: <20161228124728.26619-1-leon@kernel.org> <20161228124728.26619-2-leon@kernel.org> <1484246776.123135.19.camel@redhat.com> <20170112193508.GO20392@mtr-leonro.local> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-G/ksafZydDOux4F7le34" Return-path: In-Reply-To: <20170112193508.GO20392-U/DQcQFIOTAAJjI8aNfphQ@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Leon Romanovsky Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Feras Daoud , Noa Osherovich List-Id: linux-rdma@vger.kernel.org --=-G/ksafZydDOux4F7le34 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2017-01-12 at 21:35 +0200, Leon Romanovsky wrote: >=C2=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. =C2=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. > 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. =C2=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. =C2=A0Unless pat= h MTU support is broken, failing to set a larger MTU will not ever hinder actual operation. =C2=A0So we should never be dumping out KERN_WARN message= s 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. > >=20 > >=20 > > -- > > Doug Ledford > > =C2=A0 =C2=A0 GPG KeyID: B826A3330E572FDD > > =C2=A0 =C2=A0 > > Key fingerprint =3D AE6B 1BDA 122B 23B4 265B =C2=A01274 B826 A333 0E57 > > 2FDD >=20 >=20 --=20 Doug Ledford =C2=A0 =C2=A0 GPG KeyID: B826A3330E572FDD =C2=A0 =C2=A0 Key fingerprint =3D AE6B 1BDA 122B 23B4 265B =C2=A01274 B826 A333 0E57 2FDD --=-G/ksafZydDOux4F7le34 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAABCAAGBQJYd/wEAAoJELgmozMOVy/drOwP+wdIf5mZULxEsrOKSJTsKAoL JGwR5lLTPxa5J93sCn1OtY/WUwnFVkwngLjhua0sv0ceiIaOz4+tESkFWvIMRJ0k H/KaIWQFOVPJPR91X2ruqfTCnQbR18saPZuXnw+qj/1RRz7x8kgYgWkvUAKHWGue 549X7uwUToqEtyejjVvQnVZEW3xIBzNuKTqzlKCiES7OWNoFcMQqbwboCyMKsBoz C3+BXNSTpN/3vM2n4TLDKK0OJoq82tXLCABVW1JEbsN9ndvpvAkipmczVbjrbh8x 8XE4juI51vpRteZXeeNWMWYay7oNjTnGznnUm5kvqUg51NsO5bQrMWl/4jEAgLaG sSADxzefOJ1eQdP942sWtlzQaGmujgusOKjPBm3ZkBXR2EcFc/WYuWvDVKwPKC/s Jn9NmxySC/suzpQ5T3AdoFYRdqY9nVPYBHDGEBFYMlN+8s3hvqU2dvm8/9J016aH 7/hZmMcDnEbe7QwhShopEC83Drx77HOpIxdufpzbJGyhOjefLTlj58vYOsgQtRZK INHf2vqnUmUZWMN9M8Vbj+y6L2IHipoxNGvef007dgwDujUC5+sdH8iSI3xlWNv7 KrTs8M2gVsaSUfXSaradKRUXvRAR7hHF74nFeZ8QzZQee+J3aexNjxr/cX4XGlL4 jzzIdjtICpCzx9CigzLd =tc4x -----END PGP SIGNATURE----- --=-G/ksafZydDOux4F7le34-- -- 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