From patchwork Mon Jan 30 21:26:53 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: 649571 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 8387FC636D7 for ; Mon, 30 Jan 2023 21:27:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230496AbjA3V1P (ORCPT ); Mon, 30 Jan 2023 16:27:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230521AbjA3V1N (ORCPT ); Mon, 30 Jan 2023 16:27:13 -0500 Received: from mail-pl1-f178.google.com (mail-pl1-f178.google.com [209.85.214.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A63730E9D; Mon, 30 Jan 2023 13:27:11 -0800 (PST) Received: by mail-pl1-f178.google.com with SMTP id k13so13104651plg.0; Mon, 30 Jan 2023 13:27:11 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=gT/65YVqsvhlObcz45anS+pTHdEkcxX0FR157j8sKeY=; b=uHgwowCYxClqPFHpAd6aIrYcXcZZ99C7yI2uIvV/RvuWdD8qTLR7UJDDXWfXXNtGxq eL1K7cH6/En646uo1PDKw4EEOmDhn59t+9HAHptby/qWgn2u8frfCnl3kSbHxq/5dvMe j700VeNcHBpFNMlpYncsd4H/+zQRjyKZh57MULW0bD5mdg9xWTWH+/8fhEfhhd/WsD4K jJAHeTR+IZq8JwwL55owQwQbHd1s6YzxBEtpVYuvg3+KpWrHAYt6DHwy7fqIO4piYY36 YIrf06g29FeC8NKaw+A/UpbLB6UsL9hfIgzhAH+7BX5WfrVmxOAw1EOS7qn1EHmXW2Kc vIgQ== X-Gm-Message-State: AO0yUKVeqUIOC7OpIzAkky/eRXAXKhiupb/uFP8Cf8Pqfo03Brj1BxiX zay1v6I5GUwu+8ACbMSJ+wA= X-Google-Smtp-Source: AK7set/9cHggGNQt5QzonjVmO87KdHLRhB+xC0XkUH9ljN8l+RHD5WMOQMeuY9ZRZtnfBjQJbjHeGA== X-Received: by 2002:a17:902:f0d4:b0:196:56ae:ed19 with SMTP id v20-20020a170902f0d400b0019656aeed19mr11311882pla.2.1675114031060; Mon, 30 Jan 2023 13:27:11 -0800 (PST) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:201:5016:3bcd:59fe:334b]) by smtp.gmail.com with ESMTPSA id u18-20020a170902e5d200b00196087a3d7csm7425613plf.77.2023.01.30.13.27.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Jan 2023 13:27:10 -0800 (PST) From: Bart Van Assche To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, Jaegeuk Kim , Avri Altman , Adrian Hunter , Christoph Hellwig , Ming Lei , Bart Van Assche , Keith Busch Subject: [PATCH v4 4/7] block: Add support for filesystem requests and small segments Date: Mon, 30 Jan 2023 13:26:53 -0800 Message-Id: <20230130212656.876311-5-bvanassche@acm.org> X-Mailer: git-send-email 2.39.1.456.gfc5497dd1b-goog In-Reply-To: <20230130212656.876311-1-bvanassche@acm.org> References: <20230130212656.876311-1-bvanassche@acm.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@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. Cc: Christoph Hellwig Cc: Ming Lei Cc: Keith Busch Signed-off-by: Bart Van Assche --- block/blk-merge.c | 7 +++++-- block/blk-mq.c | 2 ++ block/blk.h | 11 +++++------ 3 files changed, 12 insertions(+), 8 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index b7c193d67185..bf21475e8a13 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -294,7 +294,8 @@ static 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, @@ -543,7 +544,9 @@ 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)) 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 9c8dc70020bc..a62b79e97a30 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2959,6 +2959,8 @@ 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 b39938255d13..5c248b80a218 100644 --- a/block/blk.h +++ b/block/blk.h @@ -333,13 +333,12 @@ 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; }