From patchwork Wed Jan 18 22:54:42 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: 643986 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 26E3CC38147 for ; Wed, 18 Jan 2023 22:55:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230073AbjARWz2 (ORCPT ); Wed, 18 Jan 2023 17:55:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230097AbjARWzD (ORCPT ); Wed, 18 Jan 2023 17:55:03 -0500 Received: from mail-pl1-f170.google.com (mail-pl1-f170.google.com [209.85.214.170]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E3F43C14; Wed, 18 Jan 2023 14:55:02 -0800 (PST) Received: by mail-pl1-f170.google.com with SMTP id v23so613610plo.1; Wed, 18 Jan 2023 14:55:02 -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=/RZDuzsMWMDJVFdLKnQsMNBF2kHeHMM55tNHIuU+tqE=; b=Q0OH0n7VBUeKpqU4UEowfmrlPhFuksOLF4tLTUlNbjg2aTQgzfM5fPfOE2WurL4sca QGmOScgGWA0E954toT1ObZcRXl3j9UNsOrBLODyzNfm95TJ+OJwS1JFzYJdvklrv4i97 ndBcGst2F2XH9nKdt+YiEslGn8a2gVgFwQXFyaqLWBs037ejwyh93c4priIUW508tHAR Csy3DzXPPeFYBhdWg6eSDNThJLzUQr96r1Y8yvxCkxNkP/+U1yLiFUis/P/QJNo63ELN 8DbVQXYueBXwoQvFcdgIWqNzy0hfyH4ABDyT07Vnp5iV1DPb+GTeSthjVrPHK32FsW2P 5alQ== X-Gm-Message-State: AFqh2kpgOw2OnjgkfU/Symzs+ZxZ1podJOMjemXexplT1wggyPRidBhc o03D6u6IIYpB0cQ/JCMU+nk= X-Google-Smtp-Source: AMrXdXs6ckHlyNDzitSnUlzG8Vr+RRJj9xORGPo4FS7GXOITkCjTy5q/LwdE/dGw47O6JSKn0XUVNA== X-Received: by 2002:a17:902:7049:b0:194:c241:f604 with SMTP id h9-20020a170902704900b00194c241f604mr2303944plt.57.1674082502046; Wed, 18 Jan 2023 14:55:02 -0800 (PST) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:201:22ae:3ae3:fde6:2308]) by smtp.gmail.com with ESMTPSA id u7-20020a17090341c700b00186e34524e3sm23649466ple.136.2023.01.18.14.55.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Jan 2023 14:55:01 -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 v3 4/9] block: Add support for filesystem requests and small segments Date: Wed, 18 Jan 2023 14:54:42 -0800 Message-Id: <20230118225447.2809787-5-bvanassche@acm.org> X-Mailer: git-send-email 2.39.0.246.g2a6d74b583-goog In-Reply-To: <20230118225447.2809787-1-bvanassche@acm.org> References: <20230118225447.2809787-1-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 | 6 ++++-- block/blk-mq.c | 2 ++ block/blk.h | 11 +++++------ 3 files changed, 11 insertions(+), 8 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index b7c193d67185..bf727f67473d 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 +544,8 @@ 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 && + 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 9d463f7563bc..947cae2def76 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 8f5e749ad73b..c3dd332ba618 100644 --- a/block/blk.h +++ b/block/blk.h @@ -316,14 +316,13 @@ 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. */ return lim->chunk_sectors || bio->bi_vcnt != 1 || +#ifdef CONFIG_BLK_SUB_PAGE_SEGMENTS + bio->bi_io_vec->bv_len > lim->max_segment_size || +#endif bio->bi_io_vec->bv_len + bio->bi_io_vec->bv_offset > PAGE_SIZE; }