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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 E927FC433DB for ; Mon, 11 Jan 2021 02:58:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB4DC224B8 for ; Mon, 11 Jan 2021 02:58:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725919AbhAKC65 (ORCPT ); Sun, 10 Jan 2021 21:58:57 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:27818 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726029AbhAKC65 (ORCPT ); Sun, 10 Jan 2021 21:58:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610333850; 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=ty7GFnFeJc6jZbRimFvcSxwHhWMZKBFI3wOaZ1vJeGo=; b=QSXTeRCwuXF+EQGvDvlSeTV6F9+UQ4+h+4xphu+zBzE4HVd2f4lGMZ+VqO1kPvemC6IZCh 5X8Br8Qn9sklnlsn/EQya6BKDw+sFt+z8LOkdrU3D4FXAsNdZROuoy340m0tVaKBUybnNJ q5cPkmaVuT/DVNI59oa1CLCJfl8M1lo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-176-lfrDpYNaMcuSG9HvsZrXJA-1; Sun, 10 Jan 2021 21:57:28 -0500 X-MC-Unique: lfrDpYNaMcuSG9HvsZrXJA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C7949180A09E; Mon, 11 Jan 2021 02:57:25 +0000 (UTC) Received: from T590 (ovpn-12-180.pek2.redhat.com [10.72.12.180]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 208EF19D9D; Mon, 11 Jan 2021 02:57:14 +0000 (UTC) Date: Mon, 11 Jan 2021 10:57:10 +0800 From: Ming Lei To: Pavel Begunkov Cc: linux-block@vger.kernel.org, Jens Axboe , Christoph Hellwig , Matthew Wilcox , Johannes Weiner , Alexander Viro , "Darrick J . Wong" , "Martin K . Petersen" , Jonathan Corbet , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, target-devel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-doc@vger.kernel.org, Christoph Hellwig Subject: Re: [PATCH v3 6/7] bio: add a helper calculating nr segments to alloc Message-ID: <20210111025710.GG4147870@T590> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Sat, Jan 09, 2021 at 04:03:02PM +0000, Pavel Begunkov wrote: > Add a helper function calculating the number of bvec segments we need to > allocate to construct a bio. It doesn't change anything functionally, > but will be used to not duplicate special cases in the future. > > Reviewed-by: Christoph Hellwig > Signed-off-by: Pavel Begunkov > --- > fs/block_dev.c | 7 ++++--- > fs/iomap/direct-io.c | 9 ++++----- > include/linux/bio.h | 10 ++++++++++ > 3 files changed, 18 insertions(+), 8 deletions(-) > > diff --git a/fs/block_dev.c b/fs/block_dev.c > index 3b8963e228a1..6f5bd9950baf 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -416,7 +416,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) > dio->size += bio->bi_iter.bi_size; > pos += bio->bi_iter.bi_size; > > - nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES); > + nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_PAGES); > if (!nr_pages) { > bool polled = false; > > @@ -481,9 +481,10 @@ blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) > { > int nr_pages; > > - nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES + 1); > - if (!nr_pages) > + if (!iov_iter_count(iter)) > return 0; > + > + nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_PAGES + 1); > if (is_sync_kiocb(iocb) && nr_pages <= BIO_MAX_PAGES) > return __blkdev_direct_IO_simple(iocb, iter, nr_pages); > > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > index 933f234d5bec..ea1e8f696076 100644 > --- a/fs/iomap/direct-io.c > +++ b/fs/iomap/direct-io.c > @@ -250,11 +250,8 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, > orig_count = iov_iter_count(dio->submit.iter); > iov_iter_truncate(dio->submit.iter, length); > > - nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); > - if (nr_pages <= 0) { > - ret = nr_pages; > + if (!iov_iter_count(dio->submit.iter)) > goto out; > - } > > if (need_zeroout) { > /* zero out from the start of the block to the write offset */ > @@ -263,6 +260,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, > iomap_dio_zero(dio, iomap, pos - pad, pad); > } > > + nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, BIO_MAX_PAGES); > do { > size_t n; > if (dio->error) { > @@ -308,7 +306,8 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, > dio->size += n; > copied += n; > > - nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); > + nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, > + BIO_MAX_PAGES); > iomap_dio_submit_bio(dio, iomap, bio, pos); > pos += n; > } while (nr_pages); > diff --git a/include/linux/bio.h b/include/linux/bio.h > index 1edda614f7ce..d8f9077c43ef 100644 > --- a/include/linux/bio.h > +++ b/include/linux/bio.h > @@ -10,6 +10,7 @@ > #include > /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */ > #include > +#include > > #define BIO_DEBUG > > @@ -441,6 +442,15 @@ static inline void bio_wouldblock_error(struct bio *bio) > bio_endio(bio); > } > > +/* > + * Calculate number of bvec segments that should be allocated to fit data > + * pointed by @iter. > + */ > +static inline int bio_iov_vecs_to_alloc(struct iov_iter *iter, int max_segs) > +{ > + return iov_iter_npages(iter, max_segs); > +} > + > struct request_queue; > > extern int submit_bio_wait(struct bio *bio); > -- > 2.24.0 > Reviewed-by: Ming Lei -- Ming