block: remove support for the host aware zone model

When zones were first added the SCSI and ATA specs, two different
models were supported (in addition to the drive managed one that
is invisible to the host):

 - host managed where non-conventional zones there is strict requirement
   to write at the write pointer, or else an error is returned
 - host aware where a write point is maintained if writes always happen
   at it, otherwise it is left in an under-defined state and the
   sequential write preferred zones behave like conventional zones
   (probably very badly performing ones, though)

Not surprisingly this lukewarm model didn't prove to be very useful and
was finally removed from the ZBC and SBC specs (NVMe never implemented
it).  Due to to the easily disappearing write pointer host software
could never rely on the write pointer to actually be useful for say
recovery.

Fortunately only a few HDD prototypes shipped using this model which
never made it to mass production.  Drop the support before it is too
late.  Note that any such host aware prototype HDD can still be used
with Linux as we'll now treat it as a conventional HDD.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20231217165359.604246-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 2 insertions, 10 deletions

diff --git a/block/partitions/core.c b/block/partitions/core.c
index f47ffcfdfcec..e6ac73617f3e 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -305,18 +305,10 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
 	 * Partitions are not supported on zoned block devices that are used as
 	 * such.
 	 */
-	switch (disk->queue->limits.zoned) {
-	case BLK_ZONED_HM:
+	if (bdev_is_zoned(disk->part0)) {
 		pr_warn("%s: partitions not supported on host managed zoned block device\n",
 			disk->disk_name);
 		return ERR_PTR(-ENXIO);
-	case BLK_ZONED_HA:
-		pr_info("%s: disabling host aware zoned block device support due to partitions\n",
-			disk->disk_name);
-		disk_set_zoned(disk, BLK_ZONED_NONE);
-		break;
-	case BLK_ZONED_NONE:
-		break;
 	}
 
 	if (xa_load(&disk->part_tbl, partno))
@@ -613,7 +605,7 @@ static int blk_add_partitions(struct gendisk *disk)
 	/*
 	 * Partitions are not supported on host managed zoned block devices.
 	 */
-	if (disk->queue->limits.zoned == BLK_ZONED_HM) {
+	if (bdev_is_zoned(disk->part0)) {
 		pr_warn("%s: ignoring partition table on host managed zoned block device\n",
 			disk->disk_name);
 		ret = 0;