WWID composed from VPD data from device, specifically page 0x83. So, when a device does not have VPD support, for example USB storage devices where VPD is specifically disabled, a read into <blk device>/device/wwid file will always return ENXIO. To avoid this, change the scsi_sdev_attr_is_visible function to hide wwid sysfs file when the devices does not support VPD. Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@xxxxxxxxx> --- drivers/scsi/scsi_sysfs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index dbb206c90ecf..bfd890fa0c69 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -1159,6 +1159,9 @@ static umode_t scsi_sdev_attr_is_visible(struct kobject *kobj, struct device *dev = container_of(kobj, struct device, kobj); struct scsi_device *sdev = to_scsi_device(dev); + /* do not present wwid if the device does not support VPD */ + if (attr == &dev_attr_wwid.attr && sdev->skip_vpd_pages) + return 0; if (attr == &dev_attr_queue_depth.attr && !sdev->host->hostt->change_queue_depth) -- 2.21.0
