From patchwork Mon Jan 30 21:26:52 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: 13121897 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 C2D93C636D6 for ; Mon, 30 Jan 2023 21:27:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230519AbjA3V1O (ORCPT ); Mon, 30 Jan 2023 16:27:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47476 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230515AbjA3V1K (ORCPT ); Mon, 30 Jan 2023 16:27:10 -0500 Received: from mail-pj1-f49.google.com (mail-pj1-f49.google.com [209.85.216.49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30E9E485A7; Mon, 30 Jan 2023 13:27:10 -0800 (PST) Received: by mail-pj1-f49.google.com with SMTP id n20-20020a17090aab9400b00229ca6a4636so16957511pjq.0; Mon, 30 Jan 2023 13:27:10 -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=idfcEYfQnXda9MtyBSs+vCtAqmQuKIMEL+tvI67zHT4=; b=CYUGwHJjHOdyqdJpHoTPbLpBV5xn+h+U5bJoS/bMdcZPdGoItDYlsskq3aInsKKZSJ Q4xhL559Sizq8cdNNFXuQ//eusGZz7sljr/LVtAxfqcqcmfwJYcUfoQWrbdVjMZb5+Fd WX6cvpY5kisDiqtC9k81beX9OA8UnnwENohBLTmeg0gqaSYD1e5XGxm+iF0G/JfYnWGZ dZpTBASl7uIqqEJxYgEUEoqT4Sw7ua+MHARXAVaxj83fypg4RSR+yUJioseSBdh5hITu N6QBJqvaArz+V8U4BkYsVoaofMFRVVZsbnodcjPKw/VKxct2uEQMaliIQfQNJ36MZAne vXpg== X-Gm-Message-State: AO0yUKWN2Ld+PeytkzfBGtOXfp3pQ+luPCW05Q7JIBYQkqHSlYOqtEnz kS7jefsjGl/B1fU6v/xKsyQ= X-Google-Smtp-Source: AK7set9yBb5kiXQ8NbiLhcIuk9sp63h3wbmDzuyqRDEXkfNmNx3bMFqDe2LHwBDOg4/bS7nPPeQUcQ== X-Received: by 2002:a17:903:32c1:b0:196:82d2:93a with SMTP id i1-20020a17090332c100b0019682d2093amr6168491plr.11.1675114029446; Mon, 30 Jan 2023 13:27:09 -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.77.2023.01.30.13.27.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Jan 2023 13:27:08 -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 3/7] block: Support submitting passthrough requests with small segments Date: Mon, 30 Jan 2023 13:26:52 -0800 Message-Id: <20230130212656.876311-4-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 If the segment size is smaller than the page size there may be multiple segments per bvec even if a bvec only contains a single page. Hence this patch. Cc: Christoph Hellwig Cc: Ming Lei Cc: Keith Busch Signed-off-by: Bart Van Assche --- block/blk-map.c | 2 +- block/blk.h | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/block/blk-map.c b/block/blk-map.c index 9ee4be4ba2f1..eb059d3a1be2 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -534,7 +534,7 @@ int blk_rq_append_bio(struct request *rq, struct bio *bio) unsigned int nr_segs = 0; bio_for_each_bvec(bv, bio, iter) - nr_segs++; + nr_segs += blk_segments(&rq->q->limits, bv.bv_len); if (!rq->bio) { blk_rq_bio_prep(rq, bio, nr_segs); diff --git a/block/blk.h b/block/blk.h index 9a56d7002efc..b39938255d13 100644 --- a/block/blk.h +++ b/block/blk.h @@ -86,6 +86,24 @@ struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs, gfp_t gfp_mask); void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs); +/* Number of DMA segments required to transfer @bytes data. */ +static inline unsigned int blk_segments(const struct queue_limits *limits, + unsigned int bytes) +{ + if (!blk_queue_sub_page_limits(limits)) + return 1; + + { + const unsigned int mss = limits->max_segment_size; + + if (bytes <= mss) + return 1; + if (is_power_of_2(mss)) + return round_up(bytes, mss) >> ilog2(mss); + return (bytes + mss - 1) / mss; + } +} + static inline bool biovec_phys_mergeable(struct request_queue *q, struct bio_vec *vec1, struct bio_vec *vec2) {