From patchwork Mon Jun 12 20:33:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 13277287 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 BF689C7EE43 for ; Mon, 12 Jun 2023 20:33:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236160AbjFLUda (ORCPT ); Mon, 12 Jun 2023 16:33:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236594AbjFLUd2 (ORCPT ); Mon, 12 Jun 2023 16:33:28 -0400 Received: from mail-pl1-f170.google.com (mail-pl1-f170.google.com [209.85.214.170]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5FA7C10CE for ; Mon, 12 Jun 2023 13:33:27 -0700 (PDT) Received: by mail-pl1-f170.google.com with SMTP id d9443c01a7336-1b3a9eae57cso15992885ad.1 for ; Mon, 12 Jun 2023 13:33:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686602007; x=1689194007; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=D76EF1PRUG4k1Tw0AWeqUDGcfk53v67F7APUOd5gLok=; b=D1eDFKnJvuKEhCmvLysekJuRq4ReyBb52w6apBOtRbBEopofhO5/PKLZZnkCFEzM1m 7E+YAFMTHMjLqdHLIvAY0mdTkllcCUT8X8n6JlDLVJ5LamZkow4jBymxguBXkaMv3oRu SSit/fN9Otxz2vxdrttcdOfHGC2l3KnwViaNIUqV/r3iU9WIBTC728l19QwW0leUePkS xzOcW8ssdIAm+8XXYJT3JtkEyed2TAZuf70QFb4y2naGNDXnfgE82EgpB8db1KRFkAFV uWj8bRk+0+QXKbChAjZVudkPfeViRBHi/4upxmBnC85zUwPXe/s/OMZimd0K5gpJ0n3B COPg== X-Gm-Message-State: AC+VfDwDIcZyQlaEDCF3Wo4c9zenOQBJUGEUFSKuGAdF+ZPQTW3LOGy8 KyD54O9T1ocBEGfj+GCu+bk= X-Google-Smtp-Source: ACHHUZ6+ywaGcwwhW/1e0+gJeV6PNofySNqKstbEfzqwcpLZqBmm/9miafUPnKio/eEZhl7jtElv7w== X-Received: by 2002:a17:902:d487:b0:1b2:22cd:9827 with SMTP id c7-20020a170902d48700b001b222cd9827mr9630245plg.1.1686602006638; Mon, 12 Jun 2023 13:33:26 -0700 (PDT) Received: from asus.hsd1.ca.comcast.net ([98.51.102.78]) by smtp.gmail.com with ESMTPSA id ji1-20020a170903324100b001b016313b1dsm3324767plb.86.2023.06.12.13.33.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Jun 2023 13:33:25 -0700 (PDT) From: Bart Van Assche To: Jens Axboe Cc: linux-block@vger.kernel.org, Christoph Hellwig , Luis Chamberlain , Sandeep Dhavale , Juan Yescas , Bart Van Assche , Ming Lei , Keith Busch Subject: [PATCH v6 6/8] block: Add support for filesystem requests and small segments Date: Mon, 12 Jun 2023 13:33:12 -0700 Message-Id: <20230612203314.17820-7-bvanassche@acm.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230612203314.17820-1-bvanassche@acm.org> References: <20230612203314.17820-1-bvanassche@acm.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Add support in the bio splitting code and also in the bio submission code for bios with segments smaller than the page size. Reviewed-by: Luis Chamberlain Tested-by: Sandeep Dhavale Cc: Christoph Hellwig Cc: Ming Lei Cc: Keith Busch Signed-off-by: Bart Van Assche --- block/blk-merge.c | 8 ++++++-- block/blk-mq.c | 2 ++ block/blk.h | 11 +++++------ 3 files changed, 13 insertions(+), 8 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 65e75efa9bd3..0b28f6df07bc 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -294,7 +294,8 @@ struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim, if (nsegs < lim->max_segments && bytes + bv.bv_len <= max_bytes && bv.bv_offset + bv.bv_len <= PAGE_SIZE) { - nsegs++; + /* single-page bvec optimization */ + nsegs += blk_segments(lim, bv.bv_len); bytes += bv.bv_len; } else { if (bvec_split_segs(lim, &bv, &nsegs, &bytes, @@ -544,7 +545,10 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, __blk_segment_map_sg_merge(q, &bvec, &bvprv, sg)) goto next_bvec; - if (bvec.bv_offset + bvec.bv_len <= PAGE_SIZE) + if (bvec.bv_offset + bvec.bv_len <= PAGE_SIZE && + (!blk_queue_sub_page_limits(&q->limits) || + bvec.bv_len <= q->limits.max_segment_size)) + /* single-segment bvec optimization */ nsegs += __blk_bvec_map_sg(bvec, sglist, sg); else nsegs += blk_bvec_map_sg(q, &bvec, sglist, sg); diff --git a/block/blk-mq.c b/block/blk-mq.c index 1749f5890606..ad787c14ea09 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2936,6 +2936,8 @@ void blk_mq_submit_bio(struct bio *bio) bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); if (!bio) return; + } else if (bio->bi_vcnt == 1) { + nr_segs = blk_segments(&q->limits, bio->bi_io_vec[0].bv_len); } if (!bio_integrity_prep(bio)) diff --git a/block/blk.h b/block/blk.h index 18b898a38c72..e905cc6364fa 100644 --- a/block/blk.h +++ b/block/blk.h @@ -332,13 +332,12 @@ static inline bool bio_may_exceed_limits(struct bio *bio, } /* - * All drivers must accept single-segments bios that are <= PAGE_SIZE. - * This is a quick and dirty check that relies on the fact that - * bi_io_vec[0] is always valid if a bio has data. The check might - * lead to occasional false negatives when bios are cloned, but compared - * to the performance impact of cloned bios themselves the loop below - * doesn't matter anyway. + * Check whether bio splitting should be performed. This check may + * trigger the bio splitting code even if splitting is not necessary. */ + if (blk_queue_sub_page_limits(lim) && bio->bi_io_vec && + bio->bi_io_vec->bv_len > lim->max_segment_size) + return true; return lim->chunk_sectors || bio->bi_vcnt != 1 || bio->bi_io_vec->bv_len + bio->bi_io_vec->bv_offset > PAGE_SIZE; }