From: John Garry <john.garry@huawei.com>
To: <axboe@kernel.dk>, <damien.lemoal@opensource.wdc.com>,
<jejb@linux.ibm.com>, <martin.petersen@oracle.com>,
<jinpu.wang@cloud.ionos.com>, <hare@suse.de>,
<bvanassche@acm.org>, <hch@lst.de>, <ming.lei@redhat.com>,
<niklas.cassel@wdc.com>
Cc: <linux-block@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-ide@vger.kernel.org>, <linux-scsi@vger.kernel.org>,
<linuxarm@huawei.com>, John Garry <john.garry@huawei.com>
Subject: [PATCH RFC v3 03/22] scsi: core: Implement reserved command handling
Date: Tue, 25 Oct 2022 18:17:57 +0800 [thread overview]
Message-ID: <1666693096-180008-4-git-send-email-john.garry@huawei.com> (raw)
In-Reply-To: <1666693096-180008-1-git-send-email-john.garry@huawei.com>
From: Hannes Reinecke <hare@suse.de>
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 <hare@suse.de>
#jpg: Set tag_set->queue_depth = shost->can_queue, and not
= shost->can_queue + shost->nr_reserved_cmds;
Signed-off-by: John Garry <john.garry@huawei.com>
---
drivers/scsi/hosts.c | 3 +++
drivers/scsi/scsi_lib.c | 2 ++
include/scsi/scsi_host.h | 15 ++++++++++++++-
3 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 12346e2297fd..db89afc37bc9 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -489,6 +489,9 @@ 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 39d4fd124375..a8c4e7c037ae 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1978,6 +1978,8 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
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->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 750ccf126377..91678c77398e 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -360,10 +360,17 @@ 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
+ * including reserved commands.
*/
int can_queue;
+ /*
+ * This determines how many commands the HBA will set aside
+ * for reserved commands.
+ */
+ 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 +618,12 @@ struct Scsi_Host {
*/
unsigned nr_hw_queues;
unsigned nr_maps;
+
+ /*
+ * Number of reserved commands to allocate, if any.
+ */
+ unsigned int nr_reserved_cmds;
+
unsigned active_mode:2;
/*
--
2.35.3
next prev parent reply other threads:[~2022-10-25 9:48 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-25 10:17 [PATCH RFC v3 00/22] blk-mq/libata/scsi: SCSI driver tagging improvements Part I John Garry
2022-10-25 10:11 ` John Garry
2022-10-25 10:17 ` [PATCH RFC v3 01/22] blk-mq: Don't get budget for reserved requests John Garry
2022-10-27 1:16 ` Damien Le Moal
2022-10-27 9:09 ` John Garry
2022-10-25 10:17 ` [PATCH RFC v3 02/22] scsi: core: Add scsi_get_dev() John Garry
2022-10-25 10:17 ` John Garry [this message]
2022-10-27 1:18 ` [PATCH RFC v3 03/22] scsi: core: Implement reserved command handling Damien Le Moal
2022-10-27 7:51 ` Hannes Reinecke
2022-10-27 8:16 ` John Garry
2022-10-27 9:11 ` John Garry
2022-10-25 10:17 ` [PATCH RFC v3 04/22] scsi: core: Add support to send reserved commands John Garry
2022-10-27 1:21 ` Damien Le Moal
2022-10-27 9:13 ` John Garry
2022-10-27 9:18 ` Damien Le Moal
2022-10-25 10:17 ` [PATCH RFC v3 05/22] scsi: core: Add support for reserved command timeout handling John Garry
2022-10-25 10:18 ` [PATCH RFC v3 06/22] scsi: libsas: Improve sas_ex_discover_expander() error handling John Garry
2022-10-25 10:18 ` [PATCH RFC v3 07/22] scsi: libsas: Notify LLDD expander found before calling sas_rphy_add() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 08/22] scsi: scsi_transport_sas: Alloc sdev for expander John Garry
2022-10-25 10:18 ` [PATCH RFC v3 09/22] scsi: libsas: Add sas_alloc_slow_task_rq() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 10/22] scsi: libsas: Add sas_queuecommand_internal() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 11/22] scsi: libsas: Add sas_internal_timeout() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 12/22] scsi: core: Use SCSI_SCAN_RESCAN in __scsi_add_device() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 13/22] scsi: scsi_transport_sas: Allocate end device target id in the rphy alloc John Garry
2022-10-25 10:18 ` [PATCH RFC v3 14/22] ata: libata-scsi: Add ata_scsi_setup_sdev() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 15/22] scsi: libsas: Add sas_ata_setup_device() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 16/22] ata: libata-scsi: Allocate sdev early in port probe John Garry
2022-10-27 1:34 ` Damien Le Moal
2022-10-27 8:11 ` Hannes Reinecke
2022-10-27 9:16 ` Damien Le Moal
2022-10-27 9:51 ` Hannes Reinecke
2022-11-07 10:09 ` John Garry
2022-11-07 10:20 ` Hannes Reinecke
2022-10-25 10:18 ` [PATCH RFC v3 17/22] scsi: libsas drivers: Reserve tags John Garry
2022-10-25 10:18 ` [PATCH RFC v3 18/22] scsi: libsas: Queue SMP commands as requests John Garry
2022-10-27 1:36 ` Damien Le Moal
2022-10-27 10:45 ` John Garry
2022-10-25 10:18 ` [PATCH RFC v3 19/22] scsi: libsas: Queue TMF " John Garry
2022-10-25 10:18 ` [PATCH RFC v3 20/22] scsi: core: Add scsi_alloc_request_hwq() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 21/22] scsi: libsas: Queue internal abort commands as requests John Garry
2022-10-29 1:15 ` chenxiang (M)
2022-11-02 10:04 ` John Garry
2022-11-03 3:09 ` chenxiang (M)
2022-10-25 10:18 ` [PATCH RFC v3 22/22] scsi: libsas: Delete sas_task_slow.timer John Garry
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