From patchwork Thu Apr 3 21:17:48 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 878139 Received: from 004.mia.mailroute.net (004.mia.mailroute.net [199.89.3.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9C6472E62A6 for ; Thu, 3 Apr 2025 21:20:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.89.3.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743715219; cv=none; b=RINTSLPKVMVXyRezvQxG2PZFFn9Meyg0hggJsDeznVIBJcMUYU83xogJ9GBh7933k2n96WWiJp3woy1kUABO4Y4s0dvuZa/Z/u7mlLAFlFmSPNcAcuHzYZgzVdK1vZ/huMzVCiUuoHOpeZ+VTbpXxUCGo5f+mHSrjOn7G0VdKQg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743715219; c=relaxed/simple; bh=8u6aKBsRuvyyKw+KQPRIlUt7vDp0fsL80YTbySuoXiY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Coczc4s2GCIZSZm8JQUOw3jLT1VEch7wPqAGuqYD8RiYn0m7Q1u0+IBauU1NZV6JkK7eV90Zpr8/26fULhKCw09pQ+JwHLI1YJ1/AZ6vJilTdZEqeKoPf0XjZQa8C7kXGEWxW0KzyuuYcg5F17V5OvzC6mMcJOPIGP+z+JYkQBA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org; spf=pass smtp.mailfrom=acm.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b=wCmXf6ft; arc=none smtp.client-ip=199.89.3.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=acm.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b="wCmXf6ft" Received: from localhost (localhost [127.0.0.1]) by 004.mia.mailroute.net (Postfix) with ESMTP id 4ZTF4t42lKzmWSLK; Thu, 3 Apr 2025 21:20:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:mime-version:references:in-reply-to :x-mailer:message-id:date:date:subject:subject:from:from :received:received; s=mr01; t=1743715213; x=1746307214; bh=7U0nx JcXoFx0gPpz4DQBiBVkPHA5xxY45iObj9TF/Zo=; b=wCmXf6ftCnhwlaFrOk6qv GC6byuPmuETS/DlbwWyKrpVhOy6YTYVy03v+JUIfOmSSl+/gX4dAhpVMjlvl5mbn KaWUWfui+nYpGHMjv0Tvb8ZiUoSuxbl9QBzpOSY1aq7bjowCq9AnivHFhNPPMxo3 LXZoUdRB5FPaNijzGxk3ZPtLnB6e4xc9TRRW/wTq/cosbsZ2Itd22dz0suPHwwoh 7E0NuEsQBEE0k3pa2KLaQRas6HDt3rHQ97Cuzev0NWX9A8Mr2qju2tEF9pw+MhYF 43E0k1bBBjL3xL1gSvx9BtiKCc+eKYBsEkMmKdSYzZx75kHu9LeJ18VfaKRWHXk8 A== X-Virus-Scanned: by MailRoute Received: from 004.mia.mailroute.net ([127.0.0.1]) by localhost (004.mia [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id nwWmZwwnlr-s; Thu, 3 Apr 2025 21:20:13 +0000 (UTC) Received: from bvanassche.mtv.corp.google.com (unknown [104.135.204.82]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 004.mia.mailroute.net (Postfix) with ESMTPSA id 4ZTF4m22qqzmWSKc; Thu, 3 Apr 2025 21:20:05 +0000 (UTC) From: Bart Van Assche To: "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, Bart Van Assche , Hannes Reinecke , John Garry , "James E.J. Bottomley" Subject: [PATCH 04/24] scsi: core: Implement reserved command handling Date: Thu, 3 Apr 2025 14:17:48 -0700 Message-ID: <20250403211937.2225615-5-bvanassche@acm.org> X-Mailer: git-send-email 2.49.0.504.g3bcea36a83-goog In-Reply-To: <20250403211937.2225615-1-bvanassche@acm.org> References: <20250403211937.2225615-1-bvanassche@acm.org> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Hannes Reinecke Quite some drivers are using management commands internally. These commands typically use the same tag pool as regular SCSI commands. Tags for these management commands are set aside before allocating the block-mq tag bitmap for regular SCSI commands. The block layer already supports this via the reserved tag mechanism. Add 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. Exclude reserved commands from .can_queue because .can_queue is visible in sysfs. Signed-off-by: Hannes Reinecke [ bvanassche: modified patch description ] Cc: John Garry Signed-off-by: Bart Van Assche --- drivers/scsi/hosts.c | 3 +++ drivers/scsi/scsi_lib.c | 4 +++- include/scsi/scsi_host.h | 22 +++++++++++++++++++++- 3 files changed, 27 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index e021f1106bea..c2c6c96781e3 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -495,6 +495,9 @@ struct Scsi_Host *scsi_host_alloc(const struct scsi_host_template *sht, int priv 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 1da26f300287..94dafa5ceaaa 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2083,7 +2083,9 @@ 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 = dev_to_node(shost->dma_dev); if (shost->hostt->tag_alloc_policy_rr) diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 26bc23419cfd..2c0f5ec1046e 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -375,10 +375,19 @@ 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 @@ -611,6 +620,11 @@ 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; @@ -631,6 +645,12 @@ 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; /*