From patchwork Wed Jan 24 09:26:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13528851 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E561617BDD for ; Wed, 24 Jan 2024 09:27:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706088435; cv=none; b=NDzk1DcGPOa8W2dDjRRfHTUauNDoFrV5lqn5burimatPj4xda8bvgRIT5503164l1aoPyO23qEuJiSPCQZznNjQt3gK/JFbK88RDzxSJjGRkLF0fDbRwV3lrDPTvHcfuLqsr6COKvsLJbW9cepWcjn+pI+BNxZs8oQ1R1a4isW0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706088435; c=relaxed/simple; bh=iP8imi2P2jlrVl+iZgOZVNBqrnbeSp419t07D7h3lQI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=ovgyhR/a8XCzznmxUJwGqBBo0n8QqAogXlsaDblXYPK3ZmQa758SwvD7dEByEkhTsCLSO521/QgwBdUl7UdIHpi+E40eRBL0P9ItsddSHznrudkxAuvDunvFrE1fE+ningwWJYild97T9WIgOvqxNWn4ra9fHjnsLqSji/spv/k= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=OdN7ke2T; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="OdN7ke2T" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=fhxoy1ygzkMQ/f2cRtIxBuIJwhUdBkG86fSKoOdym0U=; b=OdN7ke2T5f9wpa/G2BBI8Z0y6Z obRy80PtptfG4+8fb5i+PXzZgf0Rzbv3gRTuYwrLdte74eS5rwEDmiLMPY5xl9vm3DBOzQoZODaYO XNJ3FMQQUlquTupTRI+XeebJ6bDFEG5xW/CYIetjCVwHEgZApbTqS10H6eGOGCdLyn+OBztfEOhKL +UpNsvQN5/t05p1aT50z1YNnROUV1H9XSOzucm9QNLEaQiL1G8AExg1WmcXIpBfVBZFzuwGRAKOWa u95quplv9RBnzX4j4ow2irEBSFFQsaP4a3VyjexkEdbHPse5+r60K2I7Jav+CvBP6YrYo0V4SOk2g lB9s8mxw==; Received: from [2001:4bb8:188:3f09:9c13:25f:1e5b:57f9] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rSZXM-002EHm-35; Wed, 24 Jan 2024 09:27:13 +0000 From: Christoph Hellwig To: Jens Axboe Cc: linux-block@vger.kernel.org Subject: [PATCH 2/3] blk-mq: introduce a blk_mq_peek_cached_request helper Date: Wed, 24 Jan 2024 10:26:57 +0100 Message-Id: <20240124092658.2258309-3-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240124092658.2258309-1-hch@lst.de> References: <20240124092658.2258309-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Add a new helper to check if there is suitable cached request in blk_mq_submit_bio. This removes open coded logic in blk_mq_submit_bio and moves some checks that so far are in blk_mq_use_cached_rq to be performed earlier. This avoids the case where we first do check with the cached request but then later end up allocating a new one anyway and need to grab a queue reference. Signed-off-by: Christoph Hellwig --- block/blk-mq.c | 63 ++++++++++++++++++++++++++------------------------ 1 file changed, 33 insertions(+), 30 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index fbd1ec56acea4d..66df323c2b9489 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2910,22 +2910,31 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q, } /* - * Check if we can use the passed on request for submitting the passed in bio, - * and remove it from the request list if it can be used. + * Check if there is a suitable cached request and return it. */ -static bool blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug, - struct bio *bio) +static struct request *blk_mq_peek_cached_request(struct blk_plug *plug, + struct request_queue *q, blk_opf_t opf) { - enum hctx_type type = blk_mq_get_hctx_type(bio->bi_opf); - enum hctx_type hctx_type = rq->mq_hctx->type; + enum hctx_type type = blk_mq_get_hctx_type(opf); + struct request *rq; - WARN_ON_ONCE(rq_list_peek(&plug->cached_rq) != rq); + if (!plug) + return NULL; + rq = rq_list_peek(&plug->cached_rq); + if (!rq || rq->q != q) + return NULL; + if (type != rq->mq_hctx->type && + (type != HCTX_TYPE_READ || rq->mq_hctx->type != HCTX_TYPE_DEFAULT)) + return NULL; + if (op_is_flush(rq->cmd_flags) != op_is_flush(opf)) + return NULL; + return rq; +} - if (type != hctx_type && - !(type == HCTX_TYPE_READ && hctx_type == HCTX_TYPE_DEFAULT)) - return false; - if (op_is_flush(rq->cmd_flags) != op_is_flush(bio->bi_opf)) - return false; +static void blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug, + struct bio *bio) +{ + WARN_ON_ONCE(rq_list_peek(&plug->cached_rq) != rq); /* * If any qos ->throttle() end up blocking, we will have flushed the @@ -2938,7 +2947,6 @@ static bool blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug, blk_mq_rq_time_init(rq, 0); rq->cmd_flags = bio->bi_opf; INIT_LIST_HEAD(&rq->queuelist); - return true; } static void bio_set_ioprio(struct bio *bio) @@ -2975,11 +2983,7 @@ void blk_mq_submit_bio(struct bio *bio) bio = blk_queue_bounce(bio, q); bio_set_ioprio(bio); - if (plug) { - rq = rq_list_peek(&plug->cached_rq); - if (rq && rq->q != q) - rq = NULL; - } + rq = blk_mq_peek_cached_request(plug, q, bio->bi_opf); if (rq) { if (unlikely(bio_may_exceed_limits(bio, &q->limits))) { bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); @@ -2990,20 +2994,19 @@ void blk_mq_submit_bio(struct bio *bio) return; if (blk_mq_attempt_bio_merge(q, bio, nr_segs)) return; - if (blk_mq_use_cached_rq(rq, plug, bio)) - goto done; - percpu_ref_get(&q->q_usage_counter); - } else { - if (unlikely(bio_queue_enter(bio))) - return; - if (unlikely(bio_may_exceed_limits(bio, &q->limits))) { - bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); - if (!bio) - goto queue_exit; - } - if (!bio_integrity_prep(bio)) + blk_mq_use_cached_rq(rq, plug, bio); + goto done; + } + + if (unlikely(bio_queue_enter(bio))) + return; + if (unlikely(bio_may_exceed_limits(bio, &q->limits))) { + bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); + if (!bio) goto queue_exit; } + if (!bio_integrity_prep(bio)) + goto queue_exit; if (blk_mq_attempt_bio_merge(q, bio, nr_segs)) goto queue_exit;