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 500CFC04A6A for ; Wed, 16 Aug 2023 14:19:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343547AbjHPOTR convert rfc822-to-8bit (ORCPT ); Wed, 16 Aug 2023 10:19:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343598AbjHPOTL (ORCPT ); Wed, 16 Aug 2023 10:19:11 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C65772709 for ; Wed, 16 Aug 2023 07:19:09 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-160-am2Q3tsvNK6quVH2Mj_lpQ-1; Wed, 16 Aug 2023 15:19:06 +0100 X-MC-Unique: am2Q3tsvNK6quVH2Mj_lpQ-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Wed, 16 Aug 2023 15:19:02 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Wed, 16 Aug 2023 15:19:02 +0100 From: David Laight To: 'David Howells' CC: Al Viro , Linus Torvalds , Jens Axboe , "Christoph Hellwig" , Christian Brauner , "Matthew Wilcox" , Jeff Layton , "linux-fsdevel@vger.kernel.org" , "linux-block@vger.kernel.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH v3 2/2] iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc() Thread-Topic: [PATCH v3 2/2] iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc() Thread-Index: AQHZ0DpP/l59sWTPXU+UuQ9VGbJikq/s16Kg///6foCAACRpIA== Date: Wed, 16 Aug 2023 14:19:02 +0000 Message-ID: <3dabec5643b24534a1c1c51894798047@AcuMS.aculab.com> References: <03730b50cebb4a349ad8667373bb8127@AcuMS.aculab.com> <20230816120741.534415-1-dhowells@redhat.com> <20230816120741.534415-3-dhowells@redhat.com> <608853.1692190847@warthog.procyon.org.uk> In-Reply-To: <608853.1692190847@warthog.procyon.org.uk> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: David Howells > Sent: Wednesday, August 16, 2023 2:01 PM > > David Laight wrote: > > > > > Couldn't the relevant code directly call __copy_from_iter_mc() ? > > Or a version then checked iov_is_copy_mc() and then fell > > back to the standard function. > > No, because the marked iterator is handed by the coredump code to > __kernel_write_iter() and thence on to who-knows-what driver - which will call > copy_from_iter() or some such. $DRIVER shouldn't need to know about > ->copy_mc. What about ITER_BVEC_MC ?? David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)