From owner-svn-src-head@freebsd.org Fri Jun 2 19:40:35 2017 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 934E1AFA3C5 for ; Fri, 2 Jun 2017 19:40:35 +0000 (UTC) (envelope-from 0100015c6a52c2bd-bd20846f-2206-411a-9488-38aeec23acbf-000000@amazonses.com) Received: from a8-13.smtp-out.amazonses.com (a8-13.smtp-out.amazonses.com [54.240.8.13]) (using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 574F674F06 for ; Fri, 2 Jun 2017 19:40:35 +0000 (UTC) (envelope-from 0100015c6a52c2bd-bd20846f-2206-411a-9488-38aeec23acbf-000000@amazonses.com) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=ae7m2yrxjw65l2cqdpjxuucyrvy564tn; d=tarsnap.com; t=1496432428; h=Subject:To:References:Cc:From:Message-ID:Date:MIME-Version:In-Reply-To:Content-Type:Content-Transfer-Encoding; bh=0mVBrsGAyI7XcG2eK0US9wzIHW2/7FBUZJzaf4f2U/c=; b=uTLccF0lQAjb8dY3HOYz0NFf0sNz6Irq4dWU/VeNgjdjAlKq1L4ty5IAVvASKFSn gCJZdNl6OJkqJJi51KrBhWSoPMqK7Su/DeMemw+QNRRhNxRvyQ3rJFoAFBkUH9Mly1p 0UbVie3j2/qCTe+0K357UtQk0Zyxg44FBaDULEiE= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=224i4yxa5dv7c2xz3womw6peuasteono; d=amazonses.com; t=1496432428; h=Subject:To:References:Cc:From:Message-ID:Date:MIME-Version:In-Reply-To:Content-Type:Content-Transfer-Encoding:Feedback-ID; bh=0mVBrsGAyI7XcG2eK0US9wzIHW2/7FBUZJzaf4f2U/c=; b=iyRgl1VzCpXC6upD3vKiBvAYKAX64/uVrWAhIMi9msiJoTPj8HXG5+m5vR8twSbQ 0QxY9Pql1nBnybUcCma3Y/cZTCm6L9XrckQ/k1SBKbp1EntJ4qeFgv/C3wzy6qYij0/ DdE1nXB1kjIvUvjKRMfby3z32O0c9q+u9JsftEvY= Subject: Re: svn commit: r319491 - head/sys/dev/xen/netfront To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= References: <201706020703.v5273V5A085287@repo.freebsd.org> <20170602102922.stlu47ceumggu6o7@dhcp-3-128.uk.xensource.com> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org From: Colin Percival Message-ID: <0100015c6a52c2bd-bd20846f-2206-411a-9488-38aeec23acbf-000000@email.amazonses.com> Date: Fri, 2 Jun 2017 19:40:27 +0000 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20170602102922.stlu47ceumggu6o7@dhcp-3-128.uk.xensource.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-SES-Outgoing: 2017.06.02-54.240.8.13 Feedback-ID: 1.us-east-1.Lv9FVjaNvvR5llaqfLoOVbo2VxOELl7cjN0AOyXnPlk=:AmazonSES X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 02 Jun 2017 19:40:35 -0000 On 06/02/17 03:29, Roger Pau Monn� wrote: > On Fri, Jun 02, 2017 at 07:03:31AM +0000, Colin Percival wrote: >> Skip setting the MTU in the netfront driver (xn# devices) if the new MTU >> is the same as the old MTU. [...] >> Maintainers of other network interface drivers may wish to consider making >> the corresponding change; the handling of SIOCSIFMTU does not seem to >> exhibit a great deal of consistency between drivers. > > Is there any reason this check (ifp->if_mtu == ifr->ifr_mtu) is not > done at a higher level for all the drivers? It seems pointless to add > this chunk everywhere. I wondered about that. Some drivers already do this (if_sk, if_age, if_jme, if_tx, if_bge, if_vge, ...) but every driver seems to spell it differently; and many drivers do things beyond merely recording the new value and re-initializing. I certainly have no objection to seeing a more generic handling of interface MTU setting, but I don't know enough about the network stack to do this myself. -- Colin Percival Security Officer Emeritus, FreeBSD | The power to serve Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid