From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0EB01C433E0 for ; Thu, 21 Jan 2021 08:48:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB7F3239A4 for ; Thu, 21 Jan 2021 08:48:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728126AbhAUIsY (ORCPT ); Thu, 21 Jan 2021 03:48:24 -0500 Received: from mail.kernel.org ([198.145.29.99]:59822 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727975AbhAUIp1 (ORCPT ); Thu, 21 Jan 2021 03:45:27 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8E75D239CF; Thu, 21 Jan 2021 08:44:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611218683; bh=sdhfOBU4yNqElkYgqvaCMCLhYYAFwCeX+2JsdASHq9U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pw/tr8cKR42V926RFqwcUVOEAIc2fjEqU7PK/dDYzI8svTiVhMhx56AyfDfquDzVE DkVhx1slLHvE6r0b0nb57zTMOdsRTd5zF8gtJU+6pcHPepp5XRkITTzNdpEm0AZFKJ nkgZWwwlwTj6OCAsFmY23uLMquXg+D5m3VI3IK3Y= Date: Thu, 21 Jan 2021 09:44:29 +0100 From: Greg Kroah-Hartman To: Linus Torvalds Cc: Oliver Giles , Robert Karszniewicz , Christoph Hellwig , Linux Kernel Mailing List , Al Viro , Jiri Slaby Subject: Re: tty splice branch (was "Re: Splicing to/from a tty") Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 20, 2021 at 05:18:36PM -0800, Linus Torvalds wrote: > On Tue, Jan 19, 2021 at 8:44 PM Linus Torvalds > wrote: > > > > I'll come back to this tomorrow and do the line-buffered icanon case > > too (unless pull requests pile up), and then I'll be happy with the > > tty changes, and I think I can submit this series for real to Greg. > > Greg, I don't know how you want to handle this. > > I have a branch with my tty splice patches at > > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git tty-splice > > and that now includes doing that "cookie continuation" thing even for > the N_TTY icanon modes. > > It passes my local tests, and I did try a few rather odd things. And > Oliver tested an ealier version without that final commit on his load. > But... > > That tty splice thing is clearly a regression, but it's not like we > have seen a lot of reports of it, so it's clearly a very special > thing. > > End result: I'm leaving it to you to decide how you want to handle it. > You can tell me to just merge it myself as a regression fix, despite > it being fairly late in the 5.11 series. Or you can pull it into your > tty tree for linux-next and 5.12. And we can just plan to backport it > (for 5.10 and 5.11) later when it has had more wide testing. > > Another alternative is to do just that first patch immediately (the > "tty: implement write_iter" one), because that one should be the > simple case that gets sendfile() and splice() working when the > _destination_ is a tty. The "source is a tty" is the much more complex > case that the other patches deal with. Let me do this last thing. I've taken your one patch into my "tty-linus" branch and will go beat on it for a day and then ask you to pull it in for the next 5.11-rc release, and I've taken your full series into my "tty-next" branch so it will get much wider testing in linux-next for a few weeks. If it turns out that we get reports of the "splice/sendfile from a tty", we can always merge them into 5.11 and 5.10 as needed. Thanks for doing this work, greg k-h