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 ACBFEC433FE for ; Wed, 24 Nov 2021 06:09:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233357AbhKXGMs (ORCPT ); Wed, 24 Nov 2021 01:12:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229825AbhKXGMs (ORCPT ); Wed, 24 Nov 2021 01:12:48 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5909FC061574; Tue, 23 Nov 2021 22:09:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=VnSXQlcgEy2R2GmynHAo8lQX3oFv77K7HQ0kh31DPrU=; b=vn2+F00XttavJDV+X8eZkJBrYV bOfKsR8wlJu6dpWao1s8Sh6URlBi4ervS1jMWbAwvHLqq17DH3QFS+noeDGBiqIuzzlN4GfUjJId4 ce3b/kZWP3YkuIc2sEeR1bkGCtdV6p87xKuttEqvTOTBXg5IaKIe7vben3eFVB2H2RA3V2Em3zGuG V3ZUTriFGZ7CcPshtKn8mtBMPsGgnxN4BjbTzaITxF9iF8LuhitY4xbT9hNnHZSWlR//fMh/3BXf7 ZQLsmEGGxU+VsW4XG/hvtjcR3/enkJtdrQ/m6ZEqqKk9kaI9UtPEGa+tFT+KUI9jdZ62uCF2AOGHS XlWMwfSQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mplTL-003yvO-6b; Wed, 24 Nov 2021 06:09:35 +0000 Date: Tue, 23 Nov 2021 22:09:35 -0800 From: "hch@infradead.org" To: Qu Wenruo Cc: "hch@infradead.org" , Johannes Thumshirn , Linux FS Devel , "dm-devel@redhat.com" , "linux-btrfs@vger.kernel.org" Subject: Re: Any bio_clone_slow() implementation which doesn't share bi_io_vec? Message-ID: References: <5d8351f1-1b09-bff0-02f2-a417c1669607@gmx.com> <79d38fc2-cd2f-2980-2c4e-408078ce6079@gmx.com> <133792e9-b89b-bc82-04fe-41202c3453a5@gmx.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <133792e9-b89b-bc82-04fe-41202c3453a5@gmx.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Nov 24, 2021 at 07:07:18AM +0800, Qu Wenruo wrote: > In that case, the missing piece seems to be a way to convert a splitted > plain bio into a REQ_OP_ZONE_APPEND bio. > > Can this be done without slow bvec copying? Yes. I have a WIP stacking driver that converts writes to zone appends and it does just that: sector_t orig_sector = bio->bi_iter.bi_sector; unsigned int bio_flags = bio->bi_opf & ~REQ_OP_MASK; ... clone = bio_clone_fast(bio, GFP_NOIO, &bdev->write_bio_set); ... clone->bi_opf = REQ_OP_ZONE_APPEND | REQ_NOMERGE | bio_flags; bio_set_dev(clone, dev->lower_bdev); clone->bi_iter.bi_sector = zone_sector; trace_block_bio_remap(clone, disk_devt(disk), orig_sector); > > Thanks, > Qu ---end quoted text---