From patchwork Thu Nov 25 15:10:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hannes Reinecke X-Patchwork-Id: 12639319 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 D144CC433FE for ; Thu, 25 Nov 2021 15:13:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355967AbhKYPQP (ORCPT ); Thu, 25 Nov 2021 10:16:15 -0500 Received: from smtp-out1.suse.de ([195.135.220.28]:35572 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347856AbhKYPOO (ORCPT ); Thu, 25 Nov 2021 10:14:14 -0500 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 0FB9A212BD; Thu, 25 Nov 2021 15:11:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1637853062; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=iM2GjXafZNlioaQ0AMIJlIjOzPaHTWYlGaYd5U4adSI=; b=MHyYY6jsT75mGsJmYt2xS/ClT/LVd2vbPyTm7vZ6c5kYzM3pDBxE5iH9MlAI2n+pP+m4T3 yXnJ1GU3OksiNmLGUd4KVxViCajjo/J2nBJ5sgtos4K3St45s/1bgGMX2rkJp0wD1oBdGa aLGa3xMF9VPRcA/WBA5N92G9IHEhcvY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1637853062; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=iM2GjXafZNlioaQ0AMIJlIjOzPaHTWYlGaYd5U4adSI=; b=FhzqehWswRUwaZWg+1qBKSqaKUYfPljUzLhxYaahipDBqAMl3iSHbRgUY466UuzcrJUJVr tLnLm7krbDZ4i/AQ== Received: from adalid.arch.suse.de (adalid.arch.suse.de [10.161.8.13]) by relay2.suse.de (Postfix) with ESMTP id AD160A3B8A; Thu, 25 Nov 2021 15:11:01 +0000 (UTC) Received: by adalid.arch.suse.de (Postfix, from userid 16045) id 9B8B451919F2; Thu, 25 Nov 2021 16:11:01 +0100 (CET) From: Hannes Reinecke To: "Martin K. Petersen" Cc: Christoph Hellwig , James Bottomley , linux-scsi@vger.kernel.org, John Garry , Bart van Assche , Hannes Reinecke Subject: [PATCH 03/15] scsi: implement reserved command handling Date: Thu, 25 Nov 2021 16:10:36 +0100 Message-Id: <20211125151048.103910-4-hare@suse.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20211125151048.103910-1-hare@suse.de> References: <20211125151048.103910-1-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: Bart Van Assche Reviewed-by: Asutosh Das --- drivers/scsi/hosts.c | 3 +++ drivers/scsi/scsi_lib.c | 9 ++++++++- include/scsi/scsi_host.h | 22 +++++++++++++++++++++- 3 files changed, 32 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index a539fa2fb221..8ee7a7279b6b 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -482,6 +482,9 @@ 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 6fbd36c9c416..e8f1025d0ed8 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1939,7 +1939,9 @@ 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; @@ -1964,6 +1966,9 @@ void scsi_mq_destroy_tags(struct Scsi_Host *shost) * @nowait: do not wait for command allocation to succeed. * * 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, int data_direction, bool nowait) @@ -1973,6 +1978,8 @@ struct scsi_cmnd *scsi_get_internal_cmd(struct scsi_device *sdev, blk_mq_req_flags_t flags = 0; int op; + if (sdev->host->nr_reserved_cmds) + flags |= BLK_MQ_REQ_RESERVED; if (nowait) flags |= BLK_MQ_REQ_NOWAIT; op = (data_direction == DMA_TO_DEVICE) ? diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 6f49a8940dc4..7512d97aceb4 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 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 @@ -608,6 +617,11 @@ 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; @@ -626,6 +640,12 @@ 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; /*