From patchwork Mon May 3 15:03:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hannes Reinecke X-Patchwork-Id: 431053 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3560C43462 for ; Mon, 3 May 2021 15:03:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B5C7B610A0 for ; Mon, 3 May 2021 15:03:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230236AbhECPEv (ORCPT ); Mon, 3 May 2021 11:04:51 -0400 Received: from mx2.suse.de ([195.135.220.15]:40900 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230187AbhECPEk (ORCPT ); Mon, 3 May 2021 11:04:40 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 9E38BB1C2; Mon, 3 May 2021 15:03:44 +0000 (UTC) From: Hannes Reinecke To: "Martin K. Petersen" Cc: Christoph Hellwig , James Bottomley , John Garry , linux-scsi@vger.kernel.org, Hannes Reinecke Subject: [PATCH 10/18] scsi: implement reserved command handling Date: Mon, 3 May 2021 17:03:25 +0200 Message-Id: <20210503150333.130310-11-hare@suse.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210503150333.130310-1-hare@suse.de> References: <20210503150333.130310-1-hare@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org 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 Reviewed-by: John Garry --- drivers/scsi/hosts.c | 3 +++ drivers/scsi/scsi_lib.c | 10 +++++++++- drivers/scsi/scsi_sysfs.c | 2 ++ include/scsi/scsi_host.h | 22 +++++++++++++++++++++- 4 files changed, 35 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 2f162603876f..661ed7696562 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -469,6 +469,9 @@ 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 f83b04e49bae..3c83b0fabefb 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1971,7 +1971,8 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost) 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 = NUMA_NO_NODE; tag_set->flags = BLK_MQ_F_SHOULD_MERGE; @@ -1996,6 +1997,9 @@ void scsi_mq_destroy_tags(struct Scsi_Host *shost) * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT. * * Allocates a SCSI command for internal LLDD use. + * If 'nr_reserved_commands' is specified by the host the + * command will be allocated from the reserved tag pool; + * otherwise the normal tag pool will be used. */ struct scsi_cmnd *scsi_get_internal_cmd(struct scsi_device *sdev, unsigned int op, blk_mq_req_flags_t flags) @@ -2005,6 +2009,10 @@ struct scsi_cmnd *scsi_get_internal_cmd(struct scsi_device *sdev, WARN_ON_ONCE(((op & REQ_OP_MASK) != REQ_OP_SCSI_IN) && ((op & REQ_OP_MASK) != REQ_OP_SCSI_OUT)); + + if (sdev->host->nr_reserved_cmds) + flags |= BLK_MQ_REQ_RESERVED; + rq = blk_mq_alloc_request(sdev->request_queue, op, flags); if (IS_ERR(rq)) return NULL; diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index d5260d1b7b38..f4119999a402 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -371,6 +371,7 @@ static DEVICE_ATTR(eh_deadline, S_IRUGO | S_IWUSR, show_shost_eh_deadline, store shost_rd_attr(unique_id, "%u\n"); shost_rd_attr(cmd_per_lun, "%hd\n"); shost_rd_attr(can_queue, "%d\n"); +shost_rd_attr(nr_reserved_cmds, "%d\n"); shost_rd_attr(sg_tablesize, "%hu\n"); shost_rd_attr(sg_prot_tablesize, "%hu\n"); shost_rd_attr(unchecked_isa_dma, "%d\n"); @@ -422,6 +423,7 @@ static struct attribute *scsi_sysfs_shost_attrs[] = { &dev_attr_host_reset.attr, &dev_attr_eh_deadline.attr, &dev_attr_nr_hw_queues.attr, + &dev_attr_nr_reserved_cmds.attr, NULL }; diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index f115150559ca..0831b33ee186 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -367,10 +367,19 @@ 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 calculate 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 @@ -614,6 +623,11 @@ 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; @@ -632,6 +646,12 @@ 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; unsigned unchecked_isa_dma:1;