Commit c5f88522 authored May 15, 2020 by Damien Le Moal Committed by Martin K. Petersen May 19, 2020

scsi: sd: Add zoned capabilities device attribute

Export through sysfs as a scsi_disk attribute the zoned capabilities of a
disk ("zoned_cap" attribute file). This new attribute indicates in human
readable form (i.e. a string) the zoned block capabilities implemented by
the disk as found in the ZONED field of the disk block device
characteristics VPD page. The possible values are:

 - "none": ZONED=00b (not reported), regular disk

 - "host-aware": ZONED=01b, host-aware ZBC disk

 - "drive-managed": ZONED=10b, drive-managed ZBC disk (regular disk
   interface)

For completeness, also add the following value which is detected using the
device type rather than the ZONED field:

 - "host-managed": device type = 0x14 (TYPE_ZBC), host-managed ZBC disk

This new sysfs attribute is purely informational and complementary to the
"zoned" device request queue sysfs attribute as it allows applications and
user daemons (e.g.  udev) to easily differentiate regular disks from
drive-managed SMR disks without the need for direct access tools such as
provided by sg3utils.

Link: https://lore.kernel.org/r/20200515054856.1408575-1-damien.lemoal@wdc.com


Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

parent 5cac1095

drivers/scsi/sd.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -528,6 +528,21 @@ max_write_same_blocks_store(struct device dev, struct device_attribute attr,
		}
		static DEVICE_ATTR_RW(max_write_same_blocks);

		static ssize_t
		zoned_cap_show(struct device dev, struct device_attribute attr, char *buf)
		{
		struct scsi_disk *sdkp = to_scsi_disk(dev);

		if (sdkp->device->type == TYPE_ZBC)
		return sprintf(buf, "host-managed\n");
		if (sdkp->zoned == 1)
		return sprintf(buf, "host-aware\n");
		if (sdkp->zoned == 2)
		return sprintf(buf, "drive-managed\n");
		return sprintf(buf, "none\n");
		}
		static DEVICE_ATTR_RO(zoned_cap);

		static struct attribute *sd_disk_attrs[] = {
		&dev_attr_cache_type.attr,
		&dev_attr_FUA.attr,
		@@ -541,6 +556,7 @@ static struct attribute *sd_disk_attrs[] = {
		&dev_attr_zeroing_mode.attr,
		&dev_attr_max_write_same_blocks.attr,
		&dev_attr_max_medium_access_timeouts.attr,
		&dev_attr_zoned_cap.attr,
		NULL,
		};
		ATTRIBUTE_GROUPS(sd_disk);

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