[PATCH v5 21/21] ibmvfc: provide modules parameters for MQ settings

Tyrel Datwyler
2021-01-14T20:35:31Z

Add the various module parameter toggles for adjusting the MQ
characteristics at boot/load time as well as a device attribute for
changing the client scsi channel request amount.

Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
---
drivers/scsi/ibmvscsi/ibmvfc.c | 75 ++++++++++++++++++++++++++++++----
drivers/scsi/ibmvscsi/ibmvfc.h | 1 +
2 files changed, 67 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index d314dffaafc4..7097028d4cb6 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -40,6 +40,12 @@ static unsigned int disc_threads = IBMVFC_MAX_DISC_THREADS;
static unsigned int ibmvfc_debug = IBMVFC_DEBUG;
static unsigned int log_level = IBMVFC_DEFAULT_LOG_LEVEL;
static unsigned int cls3_error = IBMVFC_CLS3_ERROR;
+static unsigned int mq_enabled = IBMVFC_MQ;
+static unsigned int nr_scsi_hw_queues = IBMVFC_SCSI_HW_QUEUES;
+static unsigned int nr_scsi_channels = IBMVFC_SCSI_CHANNELS;
+static unsigned int mig_channels_only = IBMVFC_MIG_NO_SUB_TO_CRQ;
+static unsigned int mig_no_less_channels = IBMVFC_MIG_NO_N_TO_M;
+
static LIST_HEAD(ibmvfc_head);
static DEFINE_SPINLOCK(ibmvfc_driver_lock);
static struct scsi_transport_template *ibmvfc_transport_template;
@@ -49,6 +55,22 @@ MODULE_AUTHOR("Brian King <brking@linux.vnet.ibm.com>");
MODULE_LICENSE("GPL");
MODULE_VERSION(IBMVFC_DRIVER_VERSION);

+module_param_named(mq, mq_enabled, uint, S_IRUGO);
+MODULE_PARM_DESC(mq, "Enable multiqueue support. "
+ "[Default=" __stringify(IBMVFC_MQ) "]");
+module_param_named(scsi_host_queues, nr_scsi_hw_queues, uint, S_IRUGO);
+MODULE_PARM_DESC(scsi_host_queues, "Number of SCSI Host submission queues. "
+ "[Default=" __stringify(IBMVFC_SCSI_HW_QUEUES) "]");
+module_param_named(scsi_hw_channels, nr_scsi_channels, uint, S_IRUGO);
+MODULE_PARM_DESC(scsi_hw_channels, "Number of hw scsi channels to request. "
+ "[Default=" __stringify(IBMVFC_SCSI_CHANNELS) "]");
+module_param_named(mig_channels_only, mig_channels_only, uint, S_IRUGO);
+MODULE_PARM_DESC(mig_channels_only, "Prevent migration to non-channelized system. "
+ "[Default=" __stringify(IBMVFC_MIG_NO_SUB_TO_CRQ) "]");
+module_param_named(mig_no_less_channels, mig_no_less_channels, uint, S_IRUGO);
+MODULE_PARM_DESC(mig_no_less_channels, "Prevent migration to system with less channels. "
+ "[Default=" __stringify(IBMVFC_MIG_NO_N_TO_M) "]");
+
module_param_named(init_timeout, init_timeout, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(init_timeout, "Initialization timeout in seconds. "
"[Default=" __stringify(IBMVFC_INIT_TIMEOUT) "]");
@@ -926,7 +948,7 @@ static int ibmvfc_reset_crq(struct ibmvfc_host *vhost)
crq->cur = 0;

if (vhost->scsi_scrqs.scrqs) {
- for (i = 0; i < IBMVFC_SCSI_HW_QUEUES; i++) {
+ for (i = 0; i < nr_scsi_hw_queues; i++) {
scrq = &vhost->scsi_scrqs.scrqs[i];
spin_lock(scrq->q_lock);
memset(scrq->msgs.scrq, 0, PAGE_SIZE);
@@ -3397,6 +3419,37 @@ static ssize_t ibmvfc_store_log_level(struct device *dev,
return strlen(buf);
}

+static ssize_t ibmvfc_show_scsi_channels(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct Scsi_Host *shost = class_to_shost(dev);
+ struct ibmvfc_host *vhost = shost_priv(shost);
+ unsigned long flags = 0;
+ int len;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ len = snprintf(buf, PAGE_SIZE, "%d\n", vhost->client_scsi_channels);
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ return len;
+}
+
+static ssize_t ibmvfc_store_scsi_channels(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct Scsi_Host *shost = class_to_shost(dev);
+ struct ibmvfc_host *vhost = shost_priv(shost);
+ unsigned long flags = 0;
+ unsigned int channels;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ channels = simple_strtoul(buf, NULL, 10);
+ vhost->client_scsi_channels = min(channels, nr_scsi_hw_queues);
+ ibmvfc_hard_reset_host(vhost);
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ return strlen(buf);
+}
+
static DEVICE_ATTR(partition_name, S_IRUGO, ibmvfc_show_host_partition_name, NULL);
static DEVICE_ATTR(device_name, S_IRUGO, ibmvfc_show_host_device_name, NULL);
static DEVICE_ATTR(port_loc_code, S_IRUGO, ibmvfc_show_host_loc_code, NULL);
@@ -3405,6 +3458,8 @@ static DEVICE_ATTR(npiv_version, S_IRUGO, ibmvfc_show_host_npiv_version, NULL);
static DEVICE_ATTR(capabilities, S_IRUGO, ibmvfc_show_host_capabilities, NULL);
static DEVICE_ATTR(log_level, S_IRUGO | S_IWUSR,
ibmvfc_show_log_level, ibmvfc_store_log_level);
+static DEVICE_ATTR(nr_scsi_channels, S_IRUGO | S_IWUSR,
+ ibmvfc_show_scsi_channels, ibmvfc_store_scsi_channels);

#ifdef CONFIG_SCSI_IBMVFC_TRACE
/**
@@ -3461,6 +3516,7 @@ static struct device_attribute *ibmvfc_attrs[] = {
&dev_attr_npiv_version,
&dev_attr_capabilities,
&dev_attr_log_level,
+ &dev_attr_nr_scsi_channels,
NULL
};

@@ -4866,9 +4922,9 @@ static void ibmvfc_channel_enquiry(struct ibmvfc_host *vhost)
mad->common.opcode = cpu_to_be32(IBMVFC_CHANNEL_ENQUIRY);
mad->common.length = cpu_to_be16(sizeof(*mad));

- if (IBMVFC_MIG_NO_SUB_TO_CRQ)
+ if (mig_channels_only)
mad->flags |= cpu_to_be32(IBMVFC_NO_CHANNELS_TO_CRQ_SUPPORT);
- if (IBMVFC_MIG_NO_N_TO_M)
+ if (mig_no_less_channels)
mad->flags |= cpu_to_be32(IBMVFC_NO_N_TO_M_CHANNELS_SUPPORT);

ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_INIT_WAIT);
@@ -5655,13 +5711,13 @@ static int ibmvfc_init_sub_crqs(struct ibmvfc_host *vhost)

ENTER;

- vhost->scsi_scrqs.scrqs = kcalloc(IBMVFC_SCSI_HW_QUEUES,
+ vhost->scsi_scrqs.scrqs = kcalloc(nr_scsi_hw_queues,
sizeof(*vhost->scsi_scrqs.scrqs),
GFP_KERNEL);
if (!vhost->scsi_scrqs.scrqs)
return -1;

- for (i = 0; i < IBMVFC_SCSI_HW_QUEUES; i++) {
+ for (i = 0; i < nr_scsi_hw_queues; i++) {
if (ibmvfc_register_scsi_channel(vhost, i)) {
for (j = i; j > 0; j--)
ibmvfc_deregister_scsi_channel(vhost, j - 1);
@@ -5685,7 +5741,7 @@ static void ibmvfc_release_sub_crqs(struct ibmvfc_host *vhost)
if (!vhost->scsi_scrqs.scrqs)
return;

- for (i = 0; i < IBMVFC_SCSI_HW_QUEUES; i++)
+ for (i = 0; i < nr_scsi_hw_queues; i++)
ibmvfc_deregister_scsi_channel(vhost, i);

kfree(vhost->scsi_scrqs.scrqs);
@@ -5873,6 +5929,7 @@ static int ibmvfc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
struct Scsi_Host *shost;
struct device *dev = &vdev->dev;
int rc = -ENOMEM;
+ unsigned int max_scsi_queues = IBMVFC_MAX_SCSI_QUEUES;

ENTER;
shost = scsi_host_alloc(&driver_template, sizeof(*vhost));
@@ -5888,7 +5945,7 @@ static int ibmvfc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
shost->max_sectors = IBMVFC_MAX_SECTORS;
shost->max_cmd_len = IBMVFC_MAX_CDB_LEN;
shost->unique_id = shost->host_no;
- shost->nr_hw_queues = IBMVFC_MQ ? IBMVFC_SCSI_HW_QUEUES : 1;
+ shost->nr_hw_queues = mq_enabled ? min(max_scsi_queues, nr_scsi_hw_queues) : 1;

vhost = shost_priv(shost);
INIT_LIST_HEAD(&vhost->targets);
@@ -5900,8 +5957,8 @@ static int ibmvfc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
vhost->log_level = log_level;
vhost->task_set = 1;

- vhost->mq_enabled = IBMVFC_MQ;
- vhost->client_scsi_channels = IBMVFC_SCSI_CHANNELS;
+ vhost->mq_enabled = mq_enabled;
+ vhost->client_scsi_channels = min(shost->nr_hw_queues, nr_scsi_channels);
vhost->using_channels = 0;
vhost->do_enquiry = 1;

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.h b/drivers/scsi/ibmvscsi/ibmvfc.h
index 0391cb746d0b..19dcec3ae9ba 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.h
+++ b/drivers/scsi/ibmvscsi/ibmvfc.h
@@ -43,6 +43,7 @@
#define IBMVFC_CLS3_ERROR 0
#define IBMVFC_MQ 1
#define IBMVFC_SCSI_CHANNELS 8
+#define IBMVFC_MAX_SCSI_QUEUES 16
#define IBMVFC_SCSI_HW_QUEUES 8
#define IBMVFC_MIG_NO_SUB_TO_CRQ 0
#define IBMVFC_MIG_NO_N_TO_M 0
--
2.27.0