scsi: ibmvfc: Provide modules parameters for MQ settings

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.

Link: https://lore.kernel.org/r/20210114203148.246656-22-tyreld@linux.ibm.com
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index b2a7601..b96f62a 100644 (file)
--- 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 0391cb7..19dcec3 100644 (file)
--- 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