From patchwork Mon Jan 30 21:26:56 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: 648876 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 E462FC54EAA for ; Mon, 30 Jan 2023 21:27:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231158AbjA3V13 (ORCPT ); Mon, 30 Jan 2023 16:27:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230510AbjA3V1T (ORCPT ); Mon, 30 Jan 2023 16:27:19 -0500 Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96F1744BD6; Mon, 30 Jan 2023 13:27:17 -0800 (PST) Received: by mail-pl1-f169.google.com with SMTP id 5so13059211plo.3; Mon, 30 Jan 2023 13:27:17 -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=AAt+l10ON2vRWznkQT8USZE8dWAuuKP2YrkJ5a3o/kc=; b=EWZwVMtH7/KVj9y6j/SOTGZpYIeC2I6EKbmCG7w4Q6/e3U0R8Nx/qGOgPlLoxkw4de YjqbZ+xTpxJzdg8E4Ben9j1FPMc0BQ2bAzLq6Q6zwuKakqD0rbS7S1byqSkIwItrCj2k +o/7tqS7FsFe4oOSwkYCRRdAdnmhTkRIPSfDgDCnwF6vYl14Q5kzVx4wyR/CSpsA3tKD VW1l/jhL+2Rk7OgQs1h28CkyFYKjprD0h5Td0A6E4+qP4ucNvm+z1GRZ4RuIpjK4817j WLMIOFyIDXKqTkhRxM/4VyxOehVyLEaWVfvIGWY1vr6LgWASdLNzYEksW386YZHOvZy5 1u4w== X-Gm-Message-State: AO0yUKVM231MRe/jc9w69pJm3dJ//A/rnDdPbg3OEBqBAgYWUs2r9Bew CrtPg5T/kJmK4ZXN8q78HbZBI2txfEQ5YA== X-Google-Smtp-Source: AK7set9ugoOtK1jnZ+tp5EBVD4ZwPVgZ98Jxl5DFNlP/KfTLtBzZ6oTq6u3fyuklqII69bFWXTJQUQ== X-Received: by 2002:a17:902:d4cc:b0:196:3ae3:4ffe with SMTP id o12-20020a170902d4cc00b001963ae34ffemr23578957plg.41.1675114037031; Mon, 30 Jan 2023 13:27:17 -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.77.2023.01.30.13.27.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Jan 2023 13:27:15 -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 , Damien Le Moal , Chaitanya Kulkarni Subject: [PATCH v4 7/7] null_blk: Support configuring the maximum segment size Date: Mon, 30 Jan 2023 13:26:56 -0800 Message-Id: <20230130212656.876311-8-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 for configuring the maximum segment size. Add support for segments smaller than the page size. This patch enables testing segments smaller than the page size with a driver that does not call blk_rq_map_sg(). Cc: Christoph Hellwig Cc: Ming Lei Cc: Damien Le Moal Cc: Chaitanya Kulkarni Signed-off-by: Bart Van Assche --- drivers/block/null_blk/main.c | 19 ++++++++++++++++--- drivers/block/null_blk/null_blk.h | 1 + 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c index 4c601ca9552a..06eaa7ff4a86 100644 --- a/drivers/block/null_blk/main.c +++ b/drivers/block/null_blk/main.c @@ -157,6 +157,10 @@ static int g_max_sectors; module_param_named(max_sectors, g_max_sectors, int, 0444); MODULE_PARM_DESC(max_sectors, "Maximum size of a command (in 512B sectors)"); +static unsigned int g_max_segment_size = BLK_MAX_SEGMENT_SIZE; +module_param_named(max_segment_size, g_max_segment_size, int, 0444); +MODULE_PARM_DESC(max_segment_size, "Maximum size of a segment in bytes"); + static unsigned int nr_devices = 1; module_param(nr_devices, uint, 0444); MODULE_PARM_DESC(nr_devices, "Number of devices to register"); @@ -409,6 +413,7 @@ NULLB_DEVICE_ATTR(home_node, uint, NULL); NULLB_DEVICE_ATTR(queue_mode, uint, NULL); NULLB_DEVICE_ATTR(blocksize, uint, NULL); NULLB_DEVICE_ATTR(max_sectors, uint, NULL); +NULLB_DEVICE_ATTR(max_segment_size, uint, NULL); NULLB_DEVICE_ATTR(irqmode, uint, NULL); NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL); NULLB_DEVICE_ATTR(index, uint, NULL); @@ -550,6 +555,7 @@ static struct configfs_attribute *nullb_device_attrs[] = { &nullb_device_attr_queue_mode, &nullb_device_attr_blocksize, &nullb_device_attr_max_sectors, + &nullb_device_attr_max_segment_size, &nullb_device_attr_irqmode, &nullb_device_attr_hw_queue_depth, &nullb_device_attr_index, @@ -630,7 +636,8 @@ static ssize_t memb_group_features_show(struct config_item *item, char *page) return snprintf(page, PAGE_SIZE, "badblocks,blocking,blocksize,cache_size," "completion_nsec,discard,home_node,hw_queue_depth," - "irqmode,max_sectors,mbps,memory_backed,no_sched," + "irqmode,max_sectors,max_segment_size,mbps," + "memory_backed,no_sched," "poll_queues,power,queue_mode,shared_tag_bitmap,size," "submit_queues,use_per_node_hctx,virt_boundary,zoned," "zone_capacity,zone_max_active,zone_max_open," @@ -693,6 +700,7 @@ static struct nullb_device *null_alloc_dev(void) dev->queue_mode = g_queue_mode; dev->blocksize = g_bs; dev->max_sectors = g_max_sectors; + dev->max_segment_size = g_max_segment_size; dev->irqmode = g_irqmode; dev->hw_queue_depth = g_hw_queue_depth; dev->blocking = g_blocking; @@ -1234,6 +1242,8 @@ static int null_transfer(struct nullb *nullb, struct page *page, unsigned int valid_len = len; int err = 0; + WARN_ONCE(len > dev->max_segment_size, "%u > %u\n", len, + dev->max_segment_size); if (!is_write) { if (dev->zoned) valid_len = null_zone_valid_read_len(nullb, @@ -1269,7 +1279,8 @@ static int null_handle_rq(struct nullb_cmd *cmd) spin_lock_irq(&nullb->lock); rq_for_each_segment(bvec, rq, iter) { - len = bvec.bv_len; + len = min(bvec.bv_len, nullb->dev->max_segment_size); + bvec.bv_len = len; err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset, op_is_write(req_op(rq)), sector, rq->cmd_flags & REQ_FUA); @@ -1296,7 +1307,8 @@ static int null_handle_bio(struct nullb_cmd *cmd) spin_lock_irq(&nullb->lock); bio_for_each_segment(bvec, bio, iter) { - len = bvec.bv_len; + len = min(bvec.bv_len, nullb->dev->max_segment_size); + bvec.bv_len = len; err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset, op_is_write(bio_op(bio)), sector, bio->bi_opf & REQ_FUA); @@ -2125,6 +2137,7 @@ static int null_add_dev(struct nullb_device *dev) dev->max_sectors = queue_max_hw_sectors(nullb->q); dev->max_sectors = min(dev->max_sectors, BLK_DEF_MAX_SECTORS); blk_queue_max_hw_sectors(nullb->q, dev->max_sectors); + blk_queue_max_segment_size(nullb->q, dev->max_segment_size); if (dev->virt_boundary) blk_queue_virt_boundary(nullb->q, PAGE_SIZE - 1); diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/null_blk.h index eb5972c50be8..8cb73fe05fa3 100644 --- a/drivers/block/null_blk/null_blk.h +++ b/drivers/block/null_blk/null_blk.h @@ -102,6 +102,7 @@ struct nullb_device { unsigned int queue_mode; /* block interface */ unsigned int blocksize; /* block size */ unsigned int max_sectors; /* Max sectors per command */ + unsigned int max_segment_size; /* Max size of a single DMA segment. */ unsigned int irqmode; /* IRQ completion handler */ unsigned int hw_queue_depth; /* queue depth */ unsigned int index; /* index of the disk, only valid with a disk */