From: Hannes Reinecke <hare@suse.de>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: James Bottomley <james.bottomley@hansenpartnership.com>,
Christoph Hellwig <hch@lst.de>,
John Garry <john.garry@huawei.com>,
linux-scsi@vger.kernel.org, Hannes Reinecke <hare@suse.de>
Subject: [PATCH 12/31] scsi: implement reserved command handling
Date: Mon, 22 Feb 2021 14:23:46 +0100 [thread overview]
Message-ID: <20210222132405.91369-13-hare@suse.de> (raw)
In-Reply-To: <20210222132405.91369-1-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>
---
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
next prev parent reply other threads:[~2021-02-22 13:30 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-22 13:23 [PATCHv7 00/31] scsi: enable reserved commands for LLDDs Hannes Reinecke
2021-02-22 13:23 ` [PATCH 01/31] block: add flag for internal commands Hannes Reinecke
2021-02-22 13:23 ` [PATCH 02/31] scsi: add scsi_{get,put}_internal_cmd() helper Hannes Reinecke
2021-02-24 12:12 ` John Garry
2021-02-22 13:23 ` [PATCH 03/31] fnic: use internal commands Hannes Reinecke
2021-02-22 13:23 ` [PATCH 04/31] fnic: use scsi_host_busy_iter() to traverse commands Hannes Reinecke
2021-02-22 13:23 ` [PATCH 05/31] fnic: check for started requests in fnic_wq_copy_cleanup_handler() Hannes Reinecke
2021-02-22 13:23 ` [PATCH 06/31] scsi: use real inquiry data when initialising devices Hannes Reinecke
2021-02-22 13:23 ` [PATCH 07/31] scsi: Use dummy inquiry data for the host device Hannes Reinecke
2021-02-22 13:23 ` [PATCH 08/31] scsi: revamp host device handling Hannes Reinecke
2021-02-24 13:12 ` John Garry
2021-02-24 14:24 ` Hannes Reinecke
2021-02-24 14:31 ` John Garry
2021-02-24 14:35 ` Hannes Reinecke
2021-02-22 13:23 ` [PATCH 09/31] snic: use reserved commands Hannes Reinecke
2021-02-22 13:23 ` [PATCH 10/31] snic: use tagset iter for traversing commands Hannes Reinecke
2021-02-22 13:23 ` [PATCH 11/31] snic: check for started requests in snic_hba_reset_cmpl_handler() Hannes Reinecke
2021-02-22 13:23 ` Hannes Reinecke [this message]
2021-02-22 13:23 ` [PATCH 13/31] hpsa: move hpsa_hba_inquiry after scsi_add_host() Hannes Reinecke
2021-02-22 13:23 ` [PATCH 14/31] hpsa: use reserved commands Hannes Reinecke
2021-03-11 22:03 ` michael.christie
2021-05-03 9:36 ` Hannes Reinecke
2021-02-22 13:23 ` [PATCH 15/31] hpsa: use scsi_host_busy_iter() to traverse outstanding commands Hannes Reinecke
2021-02-22 13:23 ` [PATCH 16/31] hpsa: drop refcount field from CommandList Hannes Reinecke
2021-02-22 13:23 ` [PATCH 17/31] aacraid: move scsi_add_host() Hannes Reinecke
2021-02-22 13:23 ` [PATCH 18/31] aacraid: store target id in host_scribble Hannes Reinecke
2021-02-22 13:23 ` [PATCH 19/31] aacraid: use scsi_get_internal_cmd() Hannes Reinecke
2021-02-22 13:23 ` [PATCH 20/31] aacraid: use scsi_host_busy_iter() to traverse outstanding commands Hannes Reinecke
2021-02-22 13:23 ` [PATCH 21/31] mv_sas: kill mvsas_debug_issue_ssp_tmf() Hannes Reinecke
2021-02-22 13:23 ` [PATCH 22/31] pm8001: kill pm8001_issue_ssp_tmf() Hannes Reinecke
2021-02-22 13:23 ` [PATCH 23/31] pm8001: kill 'dev' argument from pm8001_exec_internal_task_abort() Hannes Reinecke
2021-02-22 13:23 ` [PATCH 24/31] pm8001: use libsas-provided domain devices for SATA Hannes Reinecke
2021-02-22 13:23 ` [PATCH 25/31] libsas: add SCSI target pointer to struct domain_device Hannes Reinecke
2021-02-22 13:24 ` [PATCH 26/31] scsi: libsas,hisi_sas,mvsas,pm8001: Allocate Scsi_cmd for slow task Hannes Reinecke
2021-03-09 11:22 ` luojiaxing
2021-03-09 14:05 ` John Garry
2021-03-11 8:51 ` luojiaxing
2021-02-22 13:24 ` [PATCH 27/31] libsas: add tag to struct sas_task Hannes Reinecke
2021-02-22 13:24 ` [PATCH 28/31] scsi: hisi_sas: Use libsas slow task SCSI command Hannes Reinecke
2021-02-22 13:24 ` [PATCH 29/31] hisi_sas: use task tag to reference the slot Hannes Reinecke
2021-03-10 1:54 ` luojiaxing
2021-02-22 13:24 ` [PATCH 30/31] mv_sas: use reserved tags and drop private tag allocation Hannes Reinecke
2021-02-22 13:24 ` [PATCH 31/31] pm8001: use block-layer tags for ccb allocation Hannes Reinecke
2021-02-23 12:31 ` John Garry
2021-02-23 10:16 ` [PATCHv7 00/31] scsi: enable reserved commands for LLDDs John Garry
2021-02-23 17:50 ` John Garry
2021-02-24 6:54 ` Hannes Reinecke
2021-02-24 8:55 ` John Garry
2021-03-06 15:11 ` Don.Brace
2021-03-16 17:57 ` Don.Brace
2021-03-29 21:47 ` Don.Brace
2021-03-11 23:53 ` michael.christie
2021-03-12 16:08 ` Hannes Reinecke
2021-03-17 17:09 ` John Garry
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