From patchwork Thu Jun 9 10:29:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Garry X-Patchwork-Id: 12875189 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 1ED63C43334 for ; Thu, 9 Jun 2022 10:36:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242483AbiFIKg1 (ORCPT ); Thu, 9 Jun 2022 06:36:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240784AbiFIKgK (ORCPT ); Thu, 9 Jun 2022 06:36:10 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37370212D91; Thu, 9 Jun 2022 03:36:08 -0700 (PDT) Received: from fraeml735-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4LJgT46dzzz689N6; Thu, 9 Jun 2022 18:34:48 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml735-chm.china.huawei.com (10.206.15.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 9 Jun 2022 12:36:06 +0200 Received: from localhost.localdomain (10.69.192.58) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 9 Jun 2022 11:36:02 +0100 From: John Garry To: , , , , , , CC: , , , , , John Garry Subject: [PATCH RFC v2 03/18] scsi: core: Implement reserved command handling Date: Thu, 9 Jun 2022 18:29:04 +0800 Message-ID: <1654770559-101375-4-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1654770559-101375-1-git-send-email-john.garry@huawei.com> References: <1654770559-101375-1-git-send-email-john.garry@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.69.192.58] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Hannes Reinecke Quite some drivers are using management commands internally, which typically use the same hardware tag pool (ie they are being allocated from the same hardware resources) as the 'normal' I/O commands. These commands are set aside before allocating the block-mq tag bitmap, so they'll never show up as busy in the tag map. The block-layer, OTOH, already has 'reserved_tags' to handle precisely this situation. So this patch adds a new field 'nr_reserved_cmds' to the SCSI host template to instruct the block layer to set aside a tag space for these management commands by using reserved tags. Signed-off-by: Hannes Reinecke Signed-off-by: John Garry --- drivers/scsi/hosts.c | 3 +++ drivers/scsi/scsi_lib.c | 6 +++++- include/scsi/scsi_host.h | 22 +++++++++++++++++++++- 3 files changed, 29 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 8352f90d997d..27296addaf63 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -474,6 +474,9 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) if (sht->virt_boundary_mask) shost->virt_boundary_mask = sht->virt_boundary_mask; + if (sht->nr_reserved_cmds) + shost->nr_reserved_cmds = sht->nr_reserved_cmds; + device_initialize(&shost->shost_gendev); dev_set_name(&shost->shost_gendev, "host%d", shost->host_no); shost->shost_gendev.bus = &scsi_bus_type; diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 6ffc9e4258a8..f6e53c6d913c 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1974,8 +1974,12 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost) else tag_set->ops = &scsi_mq_ops_no_commit; tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1; + tag_set->nr_maps = shost->nr_maps ? : 1; - tag_set->queue_depth = shost->can_queue; + tag_set->queue_depth = + shost->can_queue + shost->nr_reserved_cmds; + tag_set->reserved_tags = shost->nr_reserved_cmds; + tag_set->cmd_size = cmd_size; tag_set->numa_node = dev_to_node(shost->dma_dev); tag_set->flags = BLK_MQ_F_SHOULD_MERGE; diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 59aef1f178f5..149dcbd4125e 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -366,10 +366,19 @@ struct scsi_host_template { /* * This determines if we will use a non-interrupt driven * or an interrupt driven scheme. It is set to the maximum number - * of simultaneous commands a single hw queue in HBA will accept. + * of simultaneous commands a single hw queue in HBA will accept + * excluding internal commands. */ int can_queue; + /* + * This determines how many commands the HBA will set aside + * for internal commands. This number will be added to + * @can_queue to calcumate the maximum number of simultaneous + * commands sent to the host. + */ + int nr_reserved_cmds; + /* * In many instances, especially where disconnect / reconnect are * supported, our host also has an ID on the SCSI bus. If this is @@ -602,6 +611,11 @@ struct Scsi_Host { unsigned short max_cmd_len; int this_id; + + /* + * Number of commands this host can handle at the same time. + * This excludes reserved commands as specified by nr_reserved_cmds. + */ int can_queue; short cmd_per_lun; short unsigned int sg_tablesize; @@ -620,6 +634,12 @@ struct Scsi_Host { */ unsigned nr_hw_queues; unsigned nr_maps; + + /* + * Number of reserved commands to allocate, if any. + */ + unsigned nr_reserved_cmds; + unsigned active_mode:2; /*