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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 25005C4361B for ; Mon, 14 Dec 2020 06:58:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E1B10225A9 for ; Mon, 14 Dec 2020 06:58:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2438823AbgLNG6a (ORCPT ); Mon, 14 Dec 2020 01:58:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727672AbgLNG63 (ORCPT ); Mon, 14 Dec 2020 01:58:29 -0500 Received: from mail-ed1-x541.google.com (mail-ed1-x541.google.com [IPv6:2a00:1450:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66581C0613CF; Sun, 13 Dec 2020 22:57:49 -0800 (PST) Received: by mail-ed1-x541.google.com with SMTP id u19so16016238edx.2; Sun, 13 Dec 2020 22:57:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=SBDQ/ozr1+cMGjDjwKraN3A/q+s0aVrfJg3tJsBwW/c=; b=QvmF/vu64Ei8tR6QADdulsd7lyo1cn3N/x/le8e6+ICWMme6u7X1yVHpDnKhVV1PQu Ci3yOVEl0AVBmWSoyDWaBpd//YjERpJdy+Bni0re0LDz8TAHm7NrDKOPmoKrubq5MZ+2 toB9XQXCemEc1yBiPwEk7S21aNkH6ZTAb0+Qdefdy/w44TZf5ag9SPLvrPnkPgoyTqV2 PIC04Jaoe0g/SfzCNn6CzA2xcaLGe8ZkWY4AwmrvC2uixpwrStNMvX+2I1aMwGYmmUyQ Oh73T2RxBcRhpKRTo1ilj0rxuYeNHGtGyCU3rzgQ0obM6wvNwAxtLFDXLAXD5eTagEIL sIFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=SBDQ/ozr1+cMGjDjwKraN3A/q+s0aVrfJg3tJsBwW/c=; b=F+VCFJj3a8m+gOzPRsSrRgmlEDvnkVUPtccUIjm9setfiGUDnFgy2okwBMRddFVXPT WhLOpVPdNhfRAjOBIepwptS0Kj3a9CtAA+DK3Ea5gfT7wtubPpYpv2sztqem2CStNzGm TieCktatzOeqbqeLheJtufNOHX9SPcDkWdO25vb1jYIKgNykOSHP/jl7HiKZoIFUL3Ae 3lTgljLdMrY2JdxppO5BPdJi4lMqn8jA94HFApJs7nRqM8rbtAL/32u7qJKj4aPD3IZ7 tx55Q5b6WUwW4pvfWzHa9P0ac4FpxF9BYAmvgsRG63fCfxdLoDRxMQ2L82bikNhBXUzk HnXA== X-Gm-Message-State: AOAM531G9c1GHBR2j3mfQgxdkE9zSk2Mf4N8fGHAXjnkAA3FHOcsonOg /WMvDtzeLd5EEzFrggnrBX1b8zxHd9mYkqs2MYo= X-Google-Smtp-Source: ABdhPJy9fRCeat4gb5XKvmqoE7tXBBH2nVrfV3qBRQb1jokU/DqVjpgFa/P//03AdoLMtwqozlQM7SSYPoT/nhq5KVs= X-Received: by 2002:a05:6402:17a3:: with SMTP id j3mr23295833edy.333.1607929067913; Sun, 13 Dec 2020 22:57:47 -0800 (PST) MIME-Version: 1.0 References: <20201211135139.49232-1-selvakuma.s1@samsung.com> <20201211135139.49232-2-selvakuma.s1@samsung.com> <20201211180451.GA9103@redsun51.ssa.fujisawa.hgst.com> In-Reply-To: <20201211180451.GA9103@redsun51.ssa.fujisawa.hgst.com> From: Selva Jove Date: Mon, 14 Dec 2020 12:27:32 +0530 Message-ID: Subject: Re: [RFC PATCH v3 1/2] block: add simple copy support To: Keith Busch Cc: SelvaKumar S , linux-nvme@lists.infradead.org, axboe@kernel.dk, Damien Le Moal , Johannes Thumshirn , hch@lst.de, sagi@grimberg.me, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, martin.petersen@oracle.com, bvanassche@acm.org, mpatocka@redhat.com, hare@suse.de, dm-devel@redhat.com, snitzer@redhat.com, nj.shetty@samsung.com, joshi.k@samsung.com, javier.gonz@samsung.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 11, 2020 at 11:35 PM Keith Busch wrote: > > On Fri, Dec 11, 2020 at 07:21:38PM +0530, SelvaKumar S wrote: > > +int blk_copy_emulate(struct block_device *bdev, struct blk_copy_payload *payload, > > + gfp_t gfp_mask) > > +{ > > + struct request_queue *q = bdev_get_queue(bdev); > > + struct bio *bio; > > + void *buf = NULL; > > + int i, nr_srcs, max_range_len, ret, cur_dest, cur_size; > > + > > + nr_srcs = payload->copy_range; > > + max_range_len = q->limits.max_copy_range_sectors << SECTOR_SHIFT; > > The default value for this limit is 0, and this is the function for when > the device doesn't support copy. Are we expecting drivers to set this > value to something else for that case? Sorry. Missed that. Will add a fix. > > > + cur_dest = payload->dest; > > + buf = kvmalloc(max_range_len, GFP_ATOMIC); > > + if (!buf) > > + return -ENOMEM; > > + > > + for (i = 0; i < nr_srcs; i++) { > > + bio = bio_alloc(gfp_mask, 1); > > + bio->bi_iter.bi_sector = payload->range[i].src; > > + bio->bi_opf = REQ_OP_READ; > > + bio_set_dev(bio, bdev); > > + > > + cur_size = payload->range[i].len << SECTOR_SHIFT; > > + ret = bio_add_page(bio, virt_to_page(buf), cur_size, > > + offset_in_page(payload)); > > 'buf' is vmalloc'ed, so we don't necessarily have congituous pages. I > think you need to allocate the bio with bio_map_kern() or something like > that instead with that kind of memory. > Sure. Will use bio_map_kern(). > > + if (ret != cur_size) { > > + ret = -ENOMEM; > > + goto out; > > + } > > + > > + ret = submit_bio_wait(bio); > > + bio_put(bio); > > + if (ret) > > + goto out; > > + > > + bio = bio_alloc(gfp_mask, 1); > > + bio_set_dev(bio, bdev); > > + bio->bi_opf = REQ_OP_WRITE; > > + bio->bi_iter.bi_sector = cur_dest; > > + ret = bio_add_page(bio, virt_to_page(buf), cur_size, > > + offset_in_page(payload)); > > + if (ret != cur_size) { > > + ret = -ENOMEM; > > + goto out; > > + } > > + > > + ret = submit_bio_wait(bio); > > + bio_put(bio); > > + if (ret) > > + goto out; > > + > > + cur_dest += payload->range[i].len; > > + } > > I think this would be a faster implementation if the reads were > asynchronous with a payload buffer allocated specific to that read, and > the callback can enqueue the write part. This would allow you to > accumulate all the read data and write it in a single call. Sounds like a better approach. Will add this implementation in v4.