On 12/2/20 10:40 AM, Brian King wrote:
> On 12/1/20 6:53 PM, Tyrel Datwyler wrote:
>> +module_param_named(mig_channels_only, mig_channels_only, uint, S_IRUGO | S_IWUSR);
>> +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 | S_IWUSR);
>> +MODULE_PARM_DESC(mig_no_less_channels, "Prevent migration to system with less channels. "
>> + "[Default=" __stringify(IBMVFC_MIG_NO_N_TO_M) "]");
>
> Both of these are writeable, but it doesn't look like you do any re-negotiation
> with the VIOS for these changed settings to take effect if someone changes
> them at runtime.
For some reason I convinced myself that these could just be changed on the fly,
but yes for them to actually take effect we need to re-negotiate the channels setup.
>
>> +
>> 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) "]");
>
>> @@ -3228,6 +3250,36 @@ 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);
>
> Don't we need to do a LIP here for this new setting to go into effect?
Actually, we need a hard reset to break the CRQ Pair. A LIP will only do a NPIV
Logout/Login which keeps the existing channel setup.
-Tyrel
>
>> + 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);
>
>
>
