From mboxrd@z Thu Jan 1 00:00:00 1970 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 3B4BAC433DB for ; Mon, 22 Feb 2021 13:30:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DEBA464E27 for ; Mon, 22 Feb 2021 13:30:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231889AbhBVNa2 (ORCPT ); Mon, 22 Feb 2021 08:30:28 -0500 Received: from mx2.suse.de ([195.135.220.15]:47794 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230340AbhBVN2Q (ORCPT ); Mon, 22 Feb 2021 08:28:16 -0500 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 DF3F7AFF5; Mon, 22 Feb 2021 13:24:15 +0000 (UTC) From: Hannes Reinecke To: "Martin K. Petersen" Cc: James Bottomley , Christoph Hellwig , John Garry , linux-scsi@vger.kernel.org, Hannes Reinecke Subject: [PATCH 12/31] scsi: implement reserved command handling Date: Mon, 22 Feb 2021 14:23:46 +0100 Message-Id: <20210222132405.91369-13-hare@suse.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210222132405.91369-1-hare@suse.de> References: <20210222132405.91369-1-hare@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- drivers/scsi/hosts.c | 3 +++ drivers/scsi/scsi_lib.c | 10 +++++++++- include/scsi/scsi_host.h | 22 +++++++++++++++++++++- 3 files changed, 33 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 5cb464972682..90af1ab6f4f5 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1916,7 +1916,9 @@ 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->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; @@ -1941,6 +1943,9 @@ void scsi_mq_destroy_tags(struct Scsi_Host *shost) * @op_flags: request allocation flags * * Allocates a SCSI command for internal LLDD use. + * If 'nr_reserved_commands' is spectified 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, enum dma_data_direction data_direction, int op_flags) @@ -1950,6 +1955,9 @@ struct scsi_cmnd *scsi_get_internal_cmd(struct scsi_device *sdev, blk_mq_req_flags_t flags = 0; unsigned int op = REQ_INTERNAL | op_flags; + if (sdev->host->nr_reserved_cmds) + flags = BLK_MQ_REQ_RESERVED; + op |= (data_direction == DMA_TO_DEVICE) ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN; rq = blk_mq_alloc_request(sdev->request_queue, op, flags); diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index ecc2d9dcfdf3..e826658bcecf 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -348,10 +348,19 @@ 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 @@ -599,6 +608,11 @@ 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; @@ -616,6 +630,12 @@ struct Scsi_Host { * the total queue depth is can_queue. */ unsigned nr_hw_queues; + + /* + * Number of reserved commands to allocate, if any. + */ + unsigned nr_reserved_cmds; + unsigned active_mode:2; unsigned unchecked_isa_dma:1; -- 2.29.2