Commit b83ce214 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

sd: implement ->get_unique_id 



Add the method to query for a uniqueue ID of a given type by looking
it up in the cached device identification VPD page.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20211021060607.264371-3-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9208d414

drivers/scsi/sd.c

+39 −0
Original line number Diff line number Diff line
@@ -1757,6 +1757,44 @@ static void sd_rescan(struct device *dev) 
	sd_revalidate_disk(sdkp->disk);

}



static int sd_get_unique_id(struct gendisk *disk, u8 id[16],

		enum blk_unique_id type)

{

	struct scsi_device *sdev = scsi_disk(disk)->device;

	const struct scsi_vpd *vpd;

	const unsigned char *d;

	int ret = -ENXIO, len;



	rcu_read_lock();

	vpd = rcu_dereference(sdev->vpd_pg83);

	if (!vpd)

		goto out_unlock;



	ret = -EINVAL;

	for (d = vpd->data + 4; d < vpd->data + vpd->len; d += d[3] + 4) {

		/* we only care about designators with LU association */

		if (((d[1] >> 4) & 0x3) != 0x00)

			continue;

		if ((d[1] & 0xf) != type)

			continue;



		/*

		 * Only exit early if a 16-byte descriptor was found.  Otherwise

		 * keep looking as one with more entropy might still show up.

		 */

		len = d[3];

		if (len != 8 && len != 12 && len != 16)

			continue;

		ret = len;

		memcpy(id, d + 4, len);

		if (len == 16)

			break;

	}

out_unlock:

	rcu_read_unlock();

	return ret;

}



static char sd_pr_type(enum pr_type type)

{

	switch (type) {
@@ -1861,6 +1899,7 @@ static const struct block_device_operations sd_fops = { 
	.check_events		= sd_check_events,

	.unlock_native_capacity	= sd_unlock_native_capacity,

	.report_zones		= sd_zbc_report_zones,

	.get_unique_id		= sd_get_unique_id,

	.pr_ops			= &sd_pr_ops,

};