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 11750C433F5 for ; Thu, 19 May 2022 07:33:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231465AbiESHdD (ORCPT ); Thu, 19 May 2022 03:33:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36888 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229441AbiESHdB (ORCPT ); Thu, 19 May 2022 03:33:01 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CBC869346B; Thu, 19 May 2022 00:33:00 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id 2B1B368AFE; Thu, 19 May 2022 09:32:57 +0200 (CEST) Date: Thu, 19 May 2022 09:32:56 +0200 From: Christoph Hellwig To: Keith Busch Cc: linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, axboe@kernel.dk, Kernel Team , hch@lst.de, bvanassche@acm.org, damien.lemoal@opensource.wdc.com, Keith Busch Subject: Re: [PATCHv2 1/3] block/bio: remove duplicate append pages code Message-ID: <20220519073256.GC22301@lst.de> References: <20220518171131.3525293-1-kbusch@fb.com> <20220518171131.3525293-2-kbusch@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220518171131.3525293-2-kbusch@fb.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, May 18, 2022 at 10:11:29AM -0700, Keith Busch wrote: > From: Keith Busch > > The setup for getting pages are identical for zone append and normal IO. > Use common code for each. How about using even more common code and avoiding churn at the same time? Something like: diff --git a/block/bio.c b/block/bio.c index a3893d80dccc9..15da722ed26d1 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1158,6 +1158,37 @@ static void bio_put_pages(struct page **pages, size_t size, size_t off) put_page(pages[i]); } +static int bio_iov_add_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int offset) +{ + bool same_page = false; + + if (!__bio_try_merge_page(bio, page, len, offset, &same_page)) { + if (WARN_ON_ONCE(bio_full(bio, len))) + return -EINVAL; + __bio_add_page(bio, page, len, offset); + return 0; + } + + if (same_page) + put_page(page); + return 0; +} + +static int bio_iov_add_zone_append_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int offset) +{ + struct request_queue *q = bdev_get_queue(bio->bi_bdev); + bool same_page = false; + + if (bio_add_hw_page(q, bio, page, len, offset, + queue_max_zone_append_sectors(q), &same_page) != len) + return -EINVAL; + if (same_page) + put_page(page); + return 0; +} + #define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *)) /** @@ -1176,7 +1207,6 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt; struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt; struct page **pages = (struct page **)bv; - bool same_page = false; ssize_t size, left; unsigned len, i; size_t offset; @@ -1195,18 +1225,18 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) for (left = size, i = 0; left > 0; left -= len, i++) { struct page *page = pages[i]; + int ret; len = min_t(size_t, PAGE_SIZE - offset, left); + if (bio_op(bio) == REQ_OP_ZONE_APPEND) + ret = bio_iov_add_zone_append_page(bio, page, len, + offset); + else + ret = bio_iov_add_page(bio, page, len, offset); - if (__bio_try_merge_page(bio, page, len, offset, &same_page)) { - if (same_page) - put_page(page); - } else { - if (WARN_ON_ONCE(bio_full(bio, len))) { - bio_put_pages(pages + i, left, offset); - return -EINVAL; - } - __bio_add_page(bio, page, len, offset); + if (ret) { + bio_put_pages(pages + i, left, offset); + return ret; } offset = 0; } @@ -1215,54 +1245,6 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) return 0; } -static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter) -{ - unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt; - unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt; - struct request_queue *q = bdev_get_queue(bio->bi_bdev); - unsigned int max_append_sectors = queue_max_zone_append_sectors(q); - struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt; - struct page **pages = (struct page **)bv; - ssize_t size, left; - unsigned len, i; - size_t offset; - int ret = 0; - - if (WARN_ON_ONCE(!max_append_sectors)) - return 0; - - /* - * Move page array up in the allocated memory for the bio vecs as far as - * possible so that we can start filling biovecs from the beginning - * without overwriting the temporary page array. - */ - BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2); - pages += entries_left * (PAGE_PTRS_PER_BVEC - 1); - - size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset); - if (unlikely(size <= 0)) - return size ? size : -EFAULT; - - for (left = size, i = 0; left > 0; left -= len, i++) { - struct page *page = pages[i]; - bool same_page = false; - - len = min_t(size_t, PAGE_SIZE - offset, left); - if (bio_add_hw_page(q, bio, page, len, offset, - max_append_sectors, &same_page) != len) { - bio_put_pages(pages + i, left, offset); - ret = -EINVAL; - break; - } - if (same_page) - put_page(page); - offset = 0; - } - - iov_iter_advance(iter, size - left); - return ret; -} - /** * bio_iov_iter_get_pages - add user or kernel pages to a bio * @bio: bio to add pages to @@ -1297,10 +1279,7 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) } do { - if (bio_op(bio) == REQ_OP_ZONE_APPEND) - ret = __bio_iov_append_get_pages(bio, iter); - else - ret = __bio_iov_iter_get_pages(bio, iter); + ret = __bio_iov_iter_get_pages(bio, iter); } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0)); /* don't account direct I/O as memory stall */