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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC759C0015E for ; Fri, 14 Jul 2023 15:47:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236090AbjGNPry (ORCPT ); Fri, 14 Jul 2023 11:47:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236139AbjGNPru (ORCPT ); Fri, 14 Jul 2023 11:47:50 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ED0BA30F8; Fri, 14 Jul 2023 08:47:49 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8750C61D53; Fri, 14 Jul 2023 15:47:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2B66C433C7; Fri, 14 Jul 2023 15:47:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689349669; bh=zFqlmjpsUpD+jmVpoeLIgKaEz5lAVss4HVnOntoEqqQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=m7GjHJfH1Mk4J4pGHhjKC67W9RKCBexZJhPfF9tKMuI83eOxxqj1V6rwDDu6ba5pE 9FoyW5Yz1b3DjoSTPdDCPI+iw/BcH1oRafGZOLQvkkP0C0HR0LTKpqhhSUkWkpxxRV I+8NnBmAlPWi/P55EhXkMVWNQb96dtwGLV0FCY5o7YaS2scTIiKLlFEWaq+lNl9Zo3 KP9Od2ztH1bo4NnGWBI/VK4R4LtxQDiU1MUaNRc15XZ5tLHLeAFQhDgipPGaHaA1GM wTh2NS6yVx/NRkle4gD31WtyCHW2RhtmaUltblWcWuhQ+PBi37f6Kx6q0BgHxGiBSL AfDUF5t0Um3xw== Date: Fri, 14 Jul 2023 17:47:45 +0200 From: Christian Brauner To: Jens Axboe Cc: Arnd Bergmann , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/5] io_uring: add IORING_OP_WAITID support Message-ID: <20230714-grummeln-sitzgelegenheit-1157c2feac71@brauner> References: <20230711204352.214086-1-axboe@kernel.dk> <20230711204352.214086-6-axboe@kernel.dk> <8431d207-5e52-4f8c-a12d-276836174bad@app.fastmail.com> <048cfbce-5238-2580-2d53-2ca740e72d79@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Tue, Jul 11, 2023 at 04:18:13PM -0600, Jens Axboe wrote: > On 7/11/23 3:22 PM, Jens Axboe wrote: > > On 7/11/23 3:11?PM, Arnd Bergmann wrote: > >> On Tue, Jul 11, 2023, at 22:43, Jens Axboe wrote: > >>> This adds support for an async version of waitid(2), in a fully async > >>> version. If an event isn't immediately available, wait for a callback > >>> to trigger a retry. > >>> > >>> The format of the sqe is as follows: > >>> > >>> sqe->len The 'which', the idtype being queried/waited for. > >>> sqe->fd The 'pid' (or id) being waited for. > >>> sqe->file_index The 'options' being set. > >>> sqe->addr2 A pointer to siginfo_t, if any, being filled in. > >>> > >>> buf_index, add3, and waitid_flags are reserved/unused for now. > >>> waitid_flags will be used for options for this request type. One > >>> interesting use case may be to add multi-shot support, so that the > >>> request stays armed and posts a notification every time a monitored > >>> process state change occurs. > >>> > >>> Note that this does not support rusage, on Arnd's recommendation. > >>> > >>> See the waitid(2) man page for details on the arguments. > >>> > >>> Signed-off-by: Jens Axboe > >> > >> Does this require argument conversion for compat tasks? > >> > >> Even without the rusage argument, I think the siginfo > >> remains incompatible with 32-bit tasks, unfortunately. > > > > Hmm yes good point, if compat_siginfo and siginfo are different, then it > > does need handling for that. Would be a trivial addition, I'll make that > > change. Thanks Arnd! > > Should be fixed in the current version: > > https://git.kernel.dk/cgit/linux/commit/?h=io_uring-waitid&id=08f3dc9b7cedbd20c0f215f25c9a7814c6c601cc In kernel/signal.c in pidfd_send_signal() we have copy_siginfo_from_user_any() it seems that a similar version copy_siginfo_to_user_any() might be something to consider. We do have copy_siginfo_to_user32() and copy_siginfo_to_user(). But I may lack context why this wouldn't work here.