> +static void zfcp_fsf_req_latency(struct zfcp_fsf_req *fsf_req)
> +{
> + struct fsf_qual_latency_info *lat_inf;
> + struct zfcp_unit *unit;
> +
> + lat_inf = &fsf_req->qtcb->prefix.prot_status_qual.latency_info;
> + unit = fsf_req->unit;
> +
> + switch (fsf_req->qtcb->bottom.io.data_direction) {
> + case FSF_DATADIR_READ:
> + unit->latencies.read.channel += lat_inf->channel_lat;
> + unit->latencies.read.fabric += lat_inf->fabric_lat;
> + unit->latencies.read.counter++;
> + break;
> + case FSF_DATADIR_WRITE:
> + unit->latencies.write.channel += lat_inf->channel_lat;
> + unit->latencies.write.fabric += lat_inf->fabric_lat;
> + unit->latencies.write.counter++;
> + break;
> + case FSF_DATADIR_CMND:
> + unit->latencies.cmd.channel += lat_inf->channel_lat;
> + unit->latencies.cmd.fabric += lat_inf->fabric_lat;
> + unit->latencies.cmd.counter++;
> + break;
> + }
> +}
These statistics are concurrently updated from several cpus without
any locking. That looks like a bug.
> +zfcp_sysfs_unit_##_name##_latency_show(struct device *dev, \
> + struct device_attribute *attr, \
> + char *buf) { \
> + struct scsi_device *sdev = to_scsi_device(dev); \
> + struct zfcp_unit *unit = sdev->hostdata; \
> + struct zfcp_latencies *lat = &unit->latencies; \
> + struct zfcp_adapter *adapter = unit->port->adapter; \
> + \
> + return sprintf(buf, "%u %u %u\n", \
> + lat->_name.fabric * adapter->timer_ticks / 1000, \
> + lat->_name.channel * adapter->timer_ticks / 1000,\
> + lat->_name.counter); \
In addition they can be read concurrently from userspace without any
locking... Since you put several values together in the output I assume
this is supposed to be some sort of snapshot, which it currently isn't.
> +static int
> +zfcp_sysfs_adapter_ex_config(struct class_device *cdev,
> + struct fsf_qtcb_bottom_config **qtcb_config)
> +{
> + struct Scsi_Host *scsi_host = class_to_shost(cdev);
> + struct zfcp_adapter *adapter = (struct zfcp_adapter *)
> + scsi_host->hostdata[0];
> +
> + if (!(adapter->adapter_features & FSF_FEATURE_MEASUREMENT_DATA)) {
> + ZFCP_LOG_NORMAL("error: Enhanced measurement feature not "
> + "supported");
> + return -EOPNOTSUPP;
> + }
> +
> + *qtcb_config = kzalloc(sizeof(struct fsf_qtcb_bottom_config),
> + GFP_KERNEL);
> + if (!*qtcb_config)
> + return -ENOMEM;
> +
> + return zfcp_fsf_exchange_config_data_sync(adapter, *qtcb_config);
> +}
> +
> +static ssize_t
> +zfcp_sysfs_adapter_request_show(struct class_device *cdev, char *buf)
> +{
> + struct fsf_qtcb_bottom_config *qtcb_config;
> + int retval;
> +
> + retval = zfcp_sysfs_adapter_ex_config(cdev, &qtcb_config);
> +
> + if (!retval)
> + retval = sprintf(buf, "%lu %lu %lu\n",
> + qtcb_config->stat_info.input_req,
> + qtcb_config->stat_info.output_req,
> + qtcb_config->stat_info.control_req);
> +
> + kfree(qtcb_config);
> + return retval;
> +}
You're going to call kfree with some random value if the adapter doesn't
support the measurement data feature.
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