From patchwork Mon Feb 17 21:08:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 11387601 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3969D924 for ; Mon, 17 Feb 2020 21:08:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1ACBA20801 for ; Mon, 17 Feb 2020 21:08:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729888AbgBQVIz (ORCPT ); Mon, 17 Feb 2020 16:08:55 -0500 Received: from mail-pj1-f66.google.com ([209.85.216.66]:40790 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728444AbgBQVIz (ORCPT ); Mon, 17 Feb 2020 16:08:55 -0500 Received: by mail-pj1-f66.google.com with SMTP id 12so53419pjb.5 for ; Mon, 17 Feb 2020 13:08:55 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=nQz+s9/NC7dIiY7glYySFYWS0V805f2KdP7BLEhNNbM=; b=G8Q17RKF3HcO2jJ9v+Niqk550r42AjCLxFRhA0Mr+ZzCeGTO90zYfD3OlUVZ6+mcez Y8M3xBqEynWVEAzqzdce2+FzjrcuqkkXXb6tYfPGv4jgHGVVY0WoPKllp0c06NbF4c+j qUfME8PxFnYB3y7qR1jIhKZDlRUsx/XrThDxQH/FayHjBq7fqs9dF2syLKXiBDy+JcrN sN1Rd0PjE/lXRTbA4TTXjcWTIRVXoSyTSJcZmlz80o4JCjYELySXXsXAxu9IwLIV3JT8 hplaorRrjpRX7M/zbywvTQidBtk7CM2k1xpCHvsv2nVPB+bO2LHx/PUF1F4OF213+jVU 9u8w== X-Gm-Message-State: APjAAAUOJBqzpIav7yC7s3br8yamzdCmNwP9ZGJVPULlOKGZaOgkptFR MQLuOt51H0zJo0hk5f1Pqpg= X-Google-Smtp-Source: APXvYqxGtwLrAv+LExw8nYr28VwHN7EQ7Xv+yyQyQtjOzLTuv8hMwg4J/d+VRjV/5moM9kJqiAZPxQ== X-Received: by 2002:a17:902:8545:: with SMTP id d5mr16890033plo.116.1581973733097; Mon, 17 Feb 2020 13:08:53 -0800 (PST) Received: from asus.hsd1.ca.comcast.net ([2601:647:4000:d7:2474:e036:5bee:ca5b]) by smtp.gmail.com with ESMTPSA id h13sm362952pjc.9.2020.02.17.13.08.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Feb 2020 13:08:52 -0800 (PST) From: Bart Van Assche To: Jens Axboe Cc: linux-block@vger.kernel.org, Christoph Hellwig , Bart Van Assche , Christoph Hellwig , Ming Lei , Hannes Reinecke , Johannes Thumshirn Subject: [PATCH 5/5] null_blk: Fix changing the number of hardware queues Date: Mon, 17 Feb 2020 13:08:39 -0800 Message-Id: <20200217210839.28535-6-bvanassche@acm.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200217210839.28535-1-bvanassche@acm.org> References: <20200217210839.28535-1-bvanassche@acm.org> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Instead of initializing null_blk hardware queues explicitly after the request queue has been created, provide .init_hctx() and .exit_hctx() callback functions. The latter functions are not only called during request queue allocation but also when the number of hardware queues changes. Allocate nr_cpu_ids queues during initialization to support increasing the number of hardware queues above the initial hardware queue count. This change fixes increasing the number of hardware queues above the initial number of hardware queues and also keeps nullb->nr_queues in sync with the number of hardware queues. Cc: Christoph Hellwig Cc: Ming Lei Cc: Hannes Reinecke Cc: Johannes Thumshirn Fixes: 45919fbfe1c4 ("null_blk: Enable modifying 'submit_queues' after an instance has been configured") Signed-off-by: Bart Van Assche --- drivers/block/null_blk_main.c | 103 ++++++++++++++++++++++------------ 1 file changed, 66 insertions(+), 37 deletions(-) diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c index 7cd31d4ef709..31678c9af43f 100644 --- a/drivers/block/null_blk_main.c +++ b/drivers/block/null_blk_main.c @@ -302,6 +302,12 @@ static int nullb_apply_submit_queues(struct nullb_device *dev, if (!nullb) return 0; + /* + * Make sure that null_init_hctx() does not access nullb->queues[] past + * the end of that array. + */ + if (submit_queues > nr_cpu_ids) + return -EINVAL; set = nullb->tag_set; blk_mq_update_nr_hw_queues(set, submit_queues); return set->nr_hw_queues == submit_queues ? 0 : -ENOMEM; @@ -1408,12 +1414,6 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx, return null_handle_cmd(cmd, sector, nr_sectors, req_op(bd->rq)); } -static const struct blk_mq_ops null_mq_ops = { - .queue_rq = null_queue_rq, - .complete = null_complete_rq, - .timeout = null_timeout_rq, -}; - static void cleanup_queue(struct nullb_queue *nq) { kfree(nq->tag_map); @@ -1430,6 +1430,43 @@ static void cleanup_queues(struct nullb *nullb) kfree(nullb->queues); } +static void null_exit_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) +{ + struct nullb_queue *nq = hctx->driver_data; + struct nullb *nullb = nq->dev->nullb; + + nullb->nr_queues--; +} + +static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq) +{ + init_waitqueue_head(&nq->wait); + nq->queue_depth = nullb->queue_depth; + nq->dev = nullb->dev; +} + +static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data, + unsigned int hctx_idx) +{ + struct nullb *nullb = hctx->queue->queuedata; + struct nullb_queue *nq; + + nq = &nullb->queues[hctx_idx]; + hctx->driver_data = nq; + null_init_queue(nullb, nq); + nullb->nr_queues++; + + return 0; +} + +static const struct blk_mq_ops null_mq_ops = { + .queue_rq = null_queue_rq, + .complete = null_complete_rq, + .timeout = null_timeout_rq, + .init_hctx = null_init_hctx, + .exit_hctx = null_exit_hctx, +}; + static void null_del_dev(struct nullb *nullb) { struct nullb_device *dev = nullb->dev; @@ -1473,33 +1510,6 @@ static const struct block_device_operations null_ops = { .report_zones = null_report_zones, }; -static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq) -{ - BUG_ON(!nullb); - BUG_ON(!nq); - - init_waitqueue_head(&nq->wait); - nq->queue_depth = nullb->queue_depth; - nq->dev = nullb->dev; -} - -static void null_init_queues(struct nullb *nullb) -{ - struct request_queue *q = nullb->q; - struct blk_mq_hw_ctx *hctx; - struct nullb_queue *nq; - int i; - - queue_for_each_hw_ctx(q, hctx, i) { - if (!hctx->nr_ctx || !hctx->tags) - continue; - nq = &nullb->queues[i]; - hctx->driver_data = nq; - null_init_queue(nullb, nq); - nullb->nr_queues++; - } -} - static int setup_commands(struct nullb_queue *nq) { struct nullb_cmd *cmd; @@ -1528,8 +1538,7 @@ static int setup_commands(struct nullb_queue *nq) static int setup_queues(struct nullb *nullb) { - nullb->queues = kcalloc(nullb->dev->submit_queues, - sizeof(struct nullb_queue), + nullb->queues = kcalloc(nr_cpu_ids, sizeof(struct nullb_queue), GFP_KERNEL); if (!nullb->queues) return -ENOMEM; @@ -1675,6 +1684,27 @@ static bool null_setup_fault(void) return true; } +/* + * This function is identical to blk_mq_init_queue() except that it sets + * queuedata before .init_hctx is called. + */ +static struct request_queue *nullb_alloc_queue(struct nullb *nullb) +{ + struct request_queue *uninit_q, *q; + struct blk_mq_tag_set *set = nullb->tag_set; + + uninit_q = blk_alloc_queue_node(GFP_KERNEL, set->numa_node); + if (!uninit_q) + return ERR_PTR(-ENOMEM); + + uninit_q->queuedata = nullb; + q = blk_mq_init_allocated_queue(set, uninit_q, false); + if (IS_ERR(q)) + blk_cleanup_queue(uninit_q); + + return q; +} + static int null_add_dev(struct nullb_device *dev) { struct nullb *nullb; @@ -1714,12 +1744,11 @@ static int null_add_dev(struct nullb_device *dev) goto out_cleanup_queues; nullb->tag_set->timeout = 5 * HZ; - nullb->q = blk_mq_init_queue(nullb->tag_set); + nullb->q = nullb_alloc_queue(nullb); if (IS_ERR(nullb->q)) { rv = -ENOMEM; goto out_cleanup_tags; } - null_init_queues(nullb); } else if (dev->queue_mode == NULL_Q_BIO) { nullb->q = blk_alloc_queue_node(GFP_KERNEL, dev->home_node); if (!nullb->q) {