dm table: Fix zoned model check and zone sectors check

Commit 24f6b6036c9e ("dm table: fix zoned iterate_devices based device
capability checks") triggered dm table load failure when dm-zoned device
is set up for zoned block devices and a regular device for cache.

The commit inverted logic of two callback functions for iterate_devices:
device_is_zoned_model() and device_matches_zone_sectors(). The logic of
device_is_zoned_model() was inverted then all destination devices of all
targets in dm table are required to have the expected zoned model. This
is fine for dm-linear, dm-flakey and dm-crypt on zoned block devices
since each target has only one destination device. However, this results
in failure for dm-zoned with regular cache device since that target has
both regular block device and zoned block devices.

As for device_matches_zone_sectors(), the commit inverted the logic to
require all zoned block devices in each target have the specified
zone_sectors. This check also fails for regular block device which does
not have zones.

To avoid the check failures, fix the zone model check and the zone
sectors check. For zone model check, introduce the new feature flag
DM_TARGET_MIXED_ZONED_MODEL, and set it to dm-zoned target. When the
target has this flag, allow it to have destination devices with any
zoned model. For zone sectors check, skip the check if the destination
device is not a zoned block device. Also add comments and improve an
error message to clarify expectations to the two checks.

Fixes: 24f6b6036c9e ("dm table: fix zoned iterate_devices based device capability checks")
Signed-off-by: Shin'ichiro Kawasaki <[e-mail]>
Signed-off-by: Damien Le Moal <[e-mail]>
Signed-off-by: Mike Snitzer <[e-mail]>

drivers/md/dm-table.c

···
 	return blk_queue_zoned_model(q) != *zoned_model;
 }
 
+/*
+ * Check the device zoned model based on the target feature flag. If the target
+ * has the DM_TARGET_ZONED_HM feature flag set, host-managed zoned devices are
+ * also accepted but all devices must have the same zoned model. If the target
+ * has the DM_TARGET_MIXED_ZONED_MODEL feature set, the devices can have any
+ * zoned model with all zoned devices having the same zone size.
+ */
 static bool dm_table_supports_zoned_model(struct dm_table *t,
 					  enum blk_zoned_model zoned_model)
 {
···
 	for (i = 0; i < dm_table_get_num_targets(t); i++) {
 		ti = dm_table_get_target(t, i);
 
-		if (zoned_model == BLK_ZONED_HM &&
-		    !dm_target_supports_zoned_hm(ti->type))
-			return false;
-
-		if (!ti->type->iterate_devices ||
-		    ti->type->iterate_devices(ti, device_not_zoned_model, &zoned_model))
-			return false;
+		if (dm_target_supports_zoned_hm(ti->type)) {
+			if (!ti->type->iterate_devices ||
+			    ti->type->iterate_devices(ti, device_not_zoned_model,
+						      &zoned_model))
+				return false;
+		} else if (!dm_target_supports_mixed_zoned_model(ti->type)) {
+			if (zoned_model == BLK_ZONED_HM)
+				return false;
+		}
 	}
 
 	return true;
···
 	struct request_queue *q = bdev_get_queue(dev->bdev);
 	unsigned int *zone_sectors = data;
 
+	if (!blk_queue_is_zoned(q))
+		return 0;
+
 	return blk_queue_zone_sectors(q) != *zone_sectors;
 }
 
+/*
+ * Check consistency of zoned model and zone sectors across all targets. For
+ * zone sectors, if the destination device is a zoned block device, it shall
+ * have the specified zone_sectors.
+ */
 static int validate_hardware_zoned_model(struct dm_table *table,
 					 enum blk_zoned_model zoned_model,
 					 unsigned int zone_sectors)
···
 		return -EINVAL;
 
 	if (dm_table_any_dev_attr(table, device_not_matches_zone_sectors, &zone_sectors)) {
-		DMERR("%s: zone sectors is not consistent across all devices",
+		DMERR("%s: zone sectors is not consistent across all zoned devices",
 		      dm_device_name(table->md));
 		return -EINVAL;
 	}

drivers/md/dm-zoned-target.c

···
 static struct target_type dmz_type = {
 	.name		 = "zoned",
 	.version	 = {2, 0, 0},
-	.features	 = DM_TARGET_SINGLETON | DM_TARGET_ZONED_HM,
+	.features	 = DM_TARGET_SINGLETON | DM_TARGET_MIXED_ZONED_MODEL,
 	.module		 = THIS_MODULE,
 	.ctr		 = dmz_ctr,
 	.dtr		 = dmz_dtr,

include/linux/device-mapper.h

···
 #define dm_target_passes_integrity(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY)
 
 /*
- * Indicates that a target supports host-managed zoned block devices.
+ * Indicates support for zoned block devices:
+ * - DM_TARGET_ZONED_HM: the target also supports host-managed zoned
+ *   block devices but does not support combining different zoned models.
+ * - DM_TARGET_MIXED_ZONED_MODEL: the target supports combining multiple
+ *   devices with different zoned models.
  */
 #ifdef CONFIG_BLK_DEV_ZONED
 #define DM_TARGET_ZONED_HM		0x00000040
···
  */
 #define DM_TARGET_PASSES_CRYPTO		0x00000100
 #define dm_target_passes_crypto(type) ((type)->features & DM_TARGET_PASSES_CRYPTO)
+
+#ifdef CONFIG_BLK_DEV_ZONED
+#define DM_TARGET_MIXED_ZONED_MODEL	0x00000200
+#define dm_target_supports_mixed_zoned_model(type) \
+	((type)->features & DM_TARGET_MIXED_ZONED_MODEL)
+#else
+#define DM_TARGET_MIXED_ZONED_MODEL	0x00000000
+#define dm_target_supports_mixed_zoned_model(type) (false)
+#endif
 
 struct dm_target {
 	struct dm_table *table;