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, 20 insertions, 25 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index fa00dd503cbf..19a19eb277f5 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3117,7 +3117,6 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp)
 	struct request_queue *q = sdkp->disk->queue;
 	struct scsi_vpd *vpd;
 	u16 rot;
-	u8 zoned;
 
 	rcu_read_lock();
 	vpd = rcu_dereference(sdkp->device->vpd_pgb1);
@@ -3128,7 +3127,7 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp)
 	}
 
 	rot = get_unaligned_be16(&vpd->data[4]);
-	zoned = (vpd->data[8] >> 4) & 3;
+	sdkp->zoned = (vpd->data[8] >> 4) & 3;
 	rcu_read_unlock();
 
 	if (rot == 1) {
@@ -3138,37 +3137,33 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp)
 
 	if (sdkp->device->type == TYPE_ZBC) {
 		/*
-		 * Host-managed: Per ZBC and ZAC specifications, writes in
-		 * sequential write required zones of host-managed devices must
-		 * be aligned to the device physical block size.
+		 * Host-managed.
+		 */
+		disk_set_zoned(sdkp->disk, true);
+
+		/*
+		 * Per ZBC and ZAC specifications, writes in sequential write
+		 * required zones of host-managed devices must be aligned to
+		 * the device physical block size.
 		 */
-		disk_set_zoned(sdkp->disk, BLK_ZONED_HM);
 		blk_queue_zone_write_granularity(q, sdkp->physical_block_size);
 	} else {
-		sdkp->zoned = zoned;
-		if (sdkp->zoned == 1) {
-			/* Host-aware */
-			disk_set_zoned(sdkp->disk, BLK_ZONED_HA);
-		} else {
-			/* Regular disk or drive managed disk */
-			disk_set_zoned(sdkp->disk, BLK_ZONED_NONE);
-		}
+		/*
+		 * Anything else.  This includes host-aware device that we treat
+		 * as conventional.
+		 */
+		disk_set_zoned(sdkp->disk, false);
 	}
 
 	if (!sdkp->first_scan)
 		return;
 
-	if (blk_queue_is_zoned(q)) {
-		sd_printk(KERN_NOTICE, sdkp, "Host-%s zoned block device\n",
-		      q->limits.zoned == BLK_ZONED_HM ? "managed" : "aware");
-	} else {
-		if (sdkp->zoned == 1)
-			sd_printk(KERN_NOTICE, sdkp,
-				  "Host-aware SMR disk used as regular disk\n");
-		else if (sdkp->zoned == 2)
-			sd_printk(KERN_NOTICE, sdkp,
-				  "Drive-managed SMR disk\n");
-	}
+	if (blk_queue_is_zoned(q))
+		sd_printk(KERN_NOTICE, sdkp, "Host-managed zoned block device\n");
+	else if (sdkp->zoned == 1)
+		sd_printk(KERN_NOTICE, sdkp, "Host-aware SMR disk used as regular disk\n");
+	else if (sdkp->zoned == 2)
+		sd_printk(KERN_NOTICE, sdkp, "Drive-managed SMR disk\n");
 }
 
 /**