From patchwork Fri Mar 24 13:58:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 13186788 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 B1955C6FD1C for ; Fri, 24 Mar 2023 14:00:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232096AbjCXOA4 (ORCPT ); Fri, 24 Mar 2023 10:00:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52378 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232099AbjCXOAT (ORCPT ); Fri, 24 Mar 2023 10:00:19 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37E5F1BADE for ; Fri, 24 Mar 2023 06:59:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679666349; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NN28dKc6XxSu1a4tYzmGw6THkgXaxqwwsT/5pOpys2I=; b=FeQqoh/PNrjbdrglowUoP5HpG1RX649ygF8v7QBjRZDMScKpWKzAPhkrr5zAfk0Ofd5wMi UXxOUDsrKEpHMaXdm1W7KbgqgM/54sPACstoOWk83Cm/Cs4ngPTu0ro5vtWYNRKIevnHSe ZqwaJeE5/jVzk3bcfek5AL/++9zfQq0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-643-orZJI0ePNO2w2QP9P70RMg-1; Fri, 24 Mar 2023 09:59:04 -0400 X-MC-Unique: orZJI0ePNO2w2QP9P70RMg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5500F2817233; Fri, 24 Mar 2023 13:59:03 +0000 (UTC) Received: from localhost (ovpn-8-20.pek2.redhat.com [10.72.8.20]) by smtp.corp.redhat.com (Postfix) with ESMTP id 789294020C81; Fri, 24 Mar 2023 13:59:02 +0000 (UTC) From: Ming Lei To: Jens Axboe , io-uring@vger.kernel.org, linux-block@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Miklos Szeredi , ZiyangZhang , Xiaoguang Wang , Bernd Schubert , Pavel Begunkov , Stefan Hajnoczi , Ming Lei Subject: [PATCH V4 12/17] block: ublk_drv: cleanup ublk_copy_user_pages Date: Fri, 24 Mar 2023 21:58:03 +0800 Message-Id: <20230324135808.855245-13-ming.lei@redhat.com> In-Reply-To: <20230324135808.855245-1-ming.lei@redhat.com> References: <20230324135808.855245-1-ming.lei@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Clean up ublk_copy_user_pages() by using iov iter, and code gets simplified a lot and becomes much more readable than before. Signed-off-by: Ming Lei --- drivers/block/ublk_drv.c | 112 +++++++++++++++++---------------------- 1 file changed, 49 insertions(+), 63 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 0e7533858c1f..85ceb8c09d0e 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -419,49 +419,39 @@ static const struct block_device_operations ub_fops = { #define UBLK_MAX_PIN_PAGES 32 -struct ublk_map_data { - const struct request *rq; - unsigned long ubuf; - unsigned int len; -}; - struct ublk_io_iter { struct page *pages[UBLK_MAX_PIN_PAGES]; - unsigned pg_off; /* offset in the 1st page in pages */ - int nr_pages; /* how many page pointers in pages */ struct bio *bio; struct bvec_iter iter; }; -static inline unsigned ublk_copy_io_pages(struct ublk_io_iter *data, - unsigned max_bytes, bool to_vm) +/* return how many pages are copied */ +static void ublk_copy_io_pages(struct ublk_io_iter *data, + size_t total, size_t pg_off, int dir) { - const unsigned total = min_t(unsigned, max_bytes, - PAGE_SIZE - data->pg_off + - ((data->nr_pages - 1) << PAGE_SHIFT)); unsigned done = 0; unsigned pg_idx = 0; while (done < total) { struct bio_vec bv = bio_iter_iovec(data->bio, data->iter); - const unsigned int bytes = min3(bv.bv_len, total - done, - (unsigned)(PAGE_SIZE - data->pg_off)); + unsigned int bytes = min3(bv.bv_len, (unsigned)total - done, + (unsigned)(PAGE_SIZE - pg_off)); void *bv_buf = bvec_kmap_local(&bv); void *pg_buf = kmap_local_page(data->pages[pg_idx]); - if (to_vm) - memcpy(pg_buf + data->pg_off, bv_buf, bytes); + if (dir == ITER_DEST) + memcpy(pg_buf + pg_off, bv_buf, bytes); else - memcpy(bv_buf, pg_buf + data->pg_off, bytes); + memcpy(bv_buf, pg_buf + pg_off, bytes); kunmap_local(pg_buf); kunmap_local(bv_buf); /* advance page array */ - data->pg_off += bytes; - if (data->pg_off == PAGE_SIZE) { + pg_off += bytes; + if (pg_off == PAGE_SIZE) { pg_idx += 1; - data->pg_off = 0; + pg_off = 0; } done += bytes; @@ -475,41 +465,40 @@ static inline unsigned ublk_copy_io_pages(struct ublk_io_iter *data, data->iter = data->bio->bi_iter; } } - - return done; } -static int ublk_copy_user_pages(struct ublk_map_data *data, bool to_vm) +/* + * Copy data between request pages and io_iter, and 'offset' + * is the start point of linear offset of request. + */ +static size_t ublk_copy_user_pages(const struct request *req, + struct iov_iter *uiter, int dir) { - const unsigned int gup_flags = to_vm ? FOLL_WRITE : 0; - const unsigned long start_vm = data->ubuf; - unsigned int done = 0; struct ublk_io_iter iter = { - .pg_off = start_vm & (PAGE_SIZE - 1), - .bio = data->rq->bio, - .iter = data->rq->bio->bi_iter, + .bio = req->bio, + .iter = req->bio->bi_iter, }; - const unsigned int nr_pages = round_up(data->len + - (start_vm & (PAGE_SIZE - 1)), PAGE_SIZE) >> PAGE_SHIFT; - - while (done < nr_pages) { - const unsigned to_pin = min_t(unsigned, UBLK_MAX_PIN_PAGES, - nr_pages - done); - unsigned i, len; - - iter.nr_pages = get_user_pages_fast(start_vm + - (done << PAGE_SHIFT), to_pin, gup_flags, - iter.pages); - if (iter.nr_pages <= 0) - return done == 0 ? iter.nr_pages : done; - len = ublk_copy_io_pages(&iter, data->len, to_vm); - for (i = 0; i < iter.nr_pages; i++) { - if (to_vm) + size_t done = 0; + + while (iov_iter_count(uiter) && iter.bio) { + unsigned nr_pages; + size_t len, off; + int i; + + len = iov_iter_get_pages2(uiter, iter.pages, + iov_iter_count(uiter), + UBLK_MAX_PIN_PAGES, &off); + if (len <= 0) + return done; + + ublk_copy_io_pages(&iter, len, off, dir); + nr_pages = DIV_ROUND_UP(len + off, PAGE_SIZE); + for (i = 0; i < nr_pages; i++) { + if (dir == ITER_DEST) set_page_dirty(iter.pages[i]); put_page(iter.pages[i]); } - data->len -= len; - done += iter.nr_pages; + done += len; } return done; @@ -536,15 +525,14 @@ static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req, * context is pretty fast, see ublk_pin_user_pages */ if (ublk_need_map_req(req)) { - struct ublk_map_data data = { - .rq = req, - .ubuf = io->addr, - .len = rq_bytes, - }; + struct iov_iter iter; + struct iovec iov; + const int dir = ITER_DEST; - ublk_copy_user_pages(&data, true); + import_single_range(dir, u64_to_user_ptr(io->addr), rq_bytes, + &iov, &iter); - return rq_bytes - data.len; + return ublk_copy_user_pages(req, &iter, dir); } return rq_bytes; } @@ -556,17 +544,15 @@ static int ublk_unmap_io(const struct ublk_queue *ubq, const unsigned int rq_bytes = blk_rq_bytes(req); if (ublk_need_unmap_req(req)) { - struct ublk_map_data data = { - .rq = req, - .ubuf = io->addr, - .len = io->res, - }; + struct iov_iter iter; + struct iovec iov; + const int dir = ITER_SOURCE; WARN_ON_ONCE(io->res > rq_bytes); - ublk_copy_user_pages(&data, false); - - return io->res - data.len; + import_single_range(dir, u64_to_user_ptr(io->addr), io->res, + &iov, &iter); + return ublk_copy_user_pages(req, &iter, dir); } return rq_bytes; }