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 EB017C77B7A for ; Fri, 19 May 2023 16:49:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231514AbjESQtb (ORCPT ); Fri, 19 May 2023 12:49:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230171AbjESQtL (ORCPT ); Fri, 19 May 2023 12:49:11 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F21481BD for ; Fri, 19 May 2023 09:47:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1684514830; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=kGTp4YSqe8PMCEMeYpjLy5orX2bqNMMdtWu7X7iaM3w=; b=MK8SukoO3UiyZFTtlnQ8TDERnWS6Nm9FlZ+25m3seWGNuKzjVpjoPrVolX4cJeBqRMgXUb rUvyLapjxwLv3GoaKRiiDvPwPfYClVe4/WXPhH6Dk4lupWVpqdxbJ2xowpsfd35pnqHAor /61y6UGaVUxCN7ijgbxNOv6C7CogGgU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-562-qFD4N4mXO-uljX8bPPuivw-1; Fri, 19 May 2023 12:47:07 -0400 X-MC-Unique: qFD4N4mXO-uljX8bPPuivw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 769E6101A585; Fri, 19 May 2023 16:47:06 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.221]) by smtp.corp.redhat.com (Postfix) with ESMTP id CD76B2166B25; Fri, 19 May 2023 16:47:03 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <20230519074047.1739879-1-dhowells@redhat.com> <20230519074047.1739879-4-dhowells@redhat.com> To: Linus Torvalds Cc: dhowells@redhat.com, Jens Axboe , Al Viro , Christoph Hellwig , Matthew Wilcox , Jan Kara , Jeff Layton , David Hildenbrand , Jason Gunthorpe , Logan Gunthorpe , Hillf Danton , Christian Brauner , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Christoph Hellwig Subject: Re: [PATCH v20 03/32] splice: Make direct_read_splice() limit to eof where appropriate MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1845767.1684514823.1@warthog.procyon.org.uk> Date: Fri, 19 May 2023 17:47:03 +0100 Message-ID: <1845768.1684514823@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds wrote: > > + if (S_ISREG(file_inode(in)->i_mode) || > > + S_ISBLK(file_inode(in)->i_mode)) { > > This really feels fundamentally wrong to me. > > If block and regular files have this limit, they should have their own > splice_read() function that implements that limit. > > Not make everybody else check it. > > IOW, this should be a separate function ("block_splice_read()" or > whatever), not inside a generic function that other users use. This is just an optimisation to cut down the amount of bufferage allocated, so I could just drop it and leave it to userspace for now as the filesystem/block layer will stop anyway if it hits the EOF. Christoph would prefer that I call direct_splice_read() from generic_file_splice_read() in all O_DIRECT cases, if that's fine with you. David