block: improve blk_zone_wp_offset()

blk_zone_wp_offset() is always called with a struct blk_zone obtained
from the device, that is, it will never see the BLK_ZONE_COND_ACTIVE
condition. However, handling this condition makes this function more
solid and will also avoid issues when propagating cached report requests
to underlying stacked devices is implemented. Add BLK_ZONE_COND_ACTIVE
as a new case in blk_zone_wp_offset() switch.

Also while at it, change the handling of the full condition to return
UINT_MAX for the zone write pointer to reflect the fact that the write
pointer of a full zone is invalid.

Signed-off-by: Damien Le Moal <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

Author: damien-lemoal

block/blk-zoned.c

@@ -800,18 +800,18 @@ static unsigned int blk_zone_wp_offset(struct blk_zone *zone)
 	case BLK_ZONE_COND_IMP_OPEN:
 	case BLK_ZONE_COND_EXP_OPEN:
 	case BLK_ZONE_COND_CLOSED:
+	case BLK_ZONE_COND_ACTIVE:
 		return zone->wp - zone->start;
-	case BLK_ZONE_COND_FULL:
-		return zone->len;
 	case BLK_ZONE_COND_EMPTY:
 		return 0;
+	case BLK_ZONE_COND_FULL:
 	case BLK_ZONE_COND_NOT_WP:
 	case BLK_ZONE_COND_OFFLINE:
 	case BLK_ZONE_COND_READONLY:
 	default:
 		/*
-		 * Conventional, offline and read-only zones do not have a valid
-		 * write pointer.
+		 * Conventional, full, offline and read-only zones do not have
+		 * a valid write pointer.
 		 */
 		return UINT_MAX;
 	}