scsi: target: fix unmap_zeroes_data boolean initialisation

The LIO unmap_zeroes_data device attribute is mapped to the LBPRZ flag in
the READ CAPACITY(16) and Thin Provisioning VPD INQUIRY responses.

The unmap_zeroes_data attribute is exposed via configfs, where any write
value is correctly validated via strtobool(). However, when initialised via
target_configure_unmap_from_queue() it takes the value of the device's
max_write_zeroes_sectors queue limit, which is non-boolean.

A non-boolean value can be read from configfs, but attempting to write the
same value back results in -EINVAL, causing problems for configuration
utilities such as targetcli.

Link: https://marc.info/?l=target-devel&m=158213354011309
Fixes: 2237498f ("target/iblock: Convert WRITE_SAME to blkdev_issue_zeroout")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_device.c

@@ -829,7 +829,7 @@ bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
 	attrib->unmap_granularity = q->limits.discard_granularity / block_size;
 	attrib->unmap_granularity_alignment = q->limits.discard_alignment /
 								block_size;
-	attrib->unmap_zeroes_data = (q->limits.max_write_zeroes_sectors);
+	attrib->unmap_zeroes_data = !!(q->limits.max_write_zeroes_sectors);
 	return true;
 }
 EXPORT_SYMBOL(target_configure_unmap_from_queue);

include/target/target_core_base.h

@@ -682,7 +682,7 @@ struct se_dev_attrib {
 	int		force_pr_aptpl;
 	int		is_nonrot;
 	int		emulate_rest_reord;
-	int		unmap_zeroes_data;
+	bool		unmap_zeroes_data;
 	u32		hw_block_size;
 	u32		block_size;
 	u32		hw_max_sectors;