[dm-devel] [PATCH 2/4] dm: Fix staking limits for zoned block device

[Damien Le Moal]

Since blk_stack_limits() does not change the zoned model type, in
dm_calculate_queue_limits(), make sure to report the correct stacked
limits by setting the zoned model to the model of the underlying table
device, after eventual override by the target .io_hints. This allows
removing the local variables zoned_model and zone_sectors and to
simplify validate_hardware_zoned_model() interface.

Signed-off-by: Damien Le Moal <damien.lemoal at wdc.com>
---
 drivers/md/dm-table.c | 46 +++++++++++++++++++---------------------------
 1 file changed, 19 insertions(+), 27 deletions(-)

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 6545150..9ba58d3 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1438,16 +1438,17 @@ static bool dm_table_matches_zone_sectors(struct dm_table *t,
 }
 
 static int validate_hardware_zoned_model(struct dm_table *table,
-					 enum blk_zoned_model zoned_model,
-					 unsigned int zone_sectors)
+					 struct queue_limits *limits)
 {
-	if (!dm_table_supports_zoned_model(table, zoned_model)) {
+	if (!dm_table_supports_zoned_model(table, limits->zoned)) {
 		DMERR("%s: zoned model is inconsistent across all devices",
 		      dm_device_name(table->md));
 		return -EINVAL;
 	}
 
-	if (zoned_model != BLK_ZONED_NONE) {
+	if (limits->zoned != BLK_ZONED_NONE) {
+		unsigned int zone_sectors = limits->chunk_sectors;
+
 		/* Check zone size validity and compatibility */
 		if (!zone_sectors || !is_power_of_2(zone_sectors))
 			return -EINVAL;
@@ -1471,8 +1472,6 @@ int dm_calculate_queue_limits(struct dm_table *table,
 	struct dm_target *ti;
 	struct queue_limits ti_limits;
 	unsigned i;
-	enum blk_zoned_model zoned_model = BLK_ZONED_NONE;
-	unsigned int zone_sectors = 0;
 
 	blk_set_stacking_limits(limits);
 
@@ -1490,15 +1489,6 @@ int dm_calculate_queue_limits(struct dm_table *table,
 		ti->type->iterate_devices(ti, dm_set_device_limits,
 					  &ti_limits);
 
-		if (zoned_model == BLK_ZONED_NONE && ti_limits.zoned != BLK_ZONED_NONE) {
-			/*
-			 * After stacking all limits, validate all devices
-			 * in table support this zoned model and zone sectors.
-			 */
-			zoned_model = ti_limits.zoned;
-			zone_sectors = ti_limits.chunk_sectors;
-		}
-
 		/* Set I/O hints portion of queue limits */
 		if (ti->type->io_hints)
 			ti->type->io_hints(ti, &ti_limits);
@@ -1523,20 +1513,22 @@ int dm_calculate_queue_limits(struct dm_table *table,
 			       dm_device_name(table->md),
 			       (unsigned long long) ti->begin,
 			       (unsigned long long) ti->len);
+
+		if (limits->zoned == BLK_ZONED_NONE &&
+		    ti_limits.zoned != BLK_ZONED_NONE) {
+			/*
+			 * By default, the stacked limits zoned model is set to
+			 * BLK_ZONED_NONE in blk_set_stacking_limits(). Update
+			 * this model using the first target model reported
+			 * that is not BLK_ZONED_NONE. This will be either the
+			 * first target device zoned model or the model reported
+			 * by the target .io_hints.
+			 */
+			limits->zoned = ti_limits.zoned;
+		}
 	}
 
-	/*
-	 * Verify that the zoned model and zone sectors, as determined before
-	 * any .io_hints override, are the same across all devices in the table.
-	 * - but if limits->zoned is not BLK_ZONED_NONE validate match for it
-	 * - simillarly, check all devices conform to limits->chunk_sectors if
-	 *   .io_hints altered them
-	 */
-	if (limits->zoned != BLK_ZONED_NONE)
-		zoned_model = limits->zoned;
-	if (limits->chunk_sectors != zone_sectors)
-		zone_sectors = limits->chunk_sectors;
-	if (validate_hardware_zoned_model(table, zoned_model, zone_sectors))
+	if (validate_hardware_zoned_model(table, limits))
 		return -EINVAL;
 
 	return validate_hardware_logical_block_alignment(table, limits);
-- 
2.9.4

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