scsi: sd: sd_zbc: Fix handling of host-aware ZBC disks

When CONFIG_BLK_DEV_ZONED is disabled, allow using host-aware ZBC disks as
regular disks. In this case, ensure that command completion is correctly
executed by changing sd_zbc_complete() to return good_bytes instead of 0
and causing a hang during device probe (endless retries).

When CONFIG_BLK_DEV_ZONED is enabled and a host-aware disk is detected to
have partitions, it will be used as a regular disk. In this case, make sure
to not do anything in sd_zbc_revalidate_zones() as that triggers warnings.

Since all these different cases result in subtle settings of the disk queue
zoned model, introduce the block layer helper function
blk_queue_set_zoned() to generically implement setting up the effective
zoned model according to the disk type, the presence of partitions on the
disk and CONFIG_BLK_DEV_ZONED configuration.

Link: https://lore.kernel.org/r/20200915073347.832424-2-damien.lemoal@wdc.com
Fixes: b72053072c0b ("block: allow partitions on host aware zone devices")
Cc: <stable@vger.kernel.org>
Reported-by: Borislav Petkov <bp@alien8.de>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

3 files changed, 24 insertions, 14 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 95018e650f2d..06286b6aeaec 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2964,26 +2964,32 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp)
 
 	if (sdkp->device->type == TYPE_ZBC) {
 		/* Host-managed */
-		q->limits.zoned = BLK_ZONED_HM;
+		blk_queue_set_zoned(sdkp->disk, BLK_ZONED_HM);
 	} else {
 		sdkp->zoned = (buffer[8] >> 4) & 3;
-		if (sdkp->zoned == 1 && !disk_has_partitions(sdkp->disk)) {
+		if (sdkp->zoned == 1) {
 			/* Host-aware */
-			q->limits.zoned = BLK_ZONED_HA;
+			blk_queue_set_zoned(sdkp->disk, BLK_ZONED_HA);
 		} else {
-			/*
-			 * Treat drive-managed devices and host-aware devices
-			 * with partitions as regular block devices.
-			 */
-			q->limits.zoned = BLK_ZONED_NONE;
-			if (sdkp->zoned == 2 && sdkp->first_scan)
-				sd_printk(KERN_NOTICE, sdkp,
-					  "Drive-managed SMR disk\n");
+			/* Regular disk or drive managed disk */
+			blk_queue_set_zoned(sdkp->disk, BLK_ZONED_NONE);
 		}
 	}
-	if (blk_queue_is_zoned(q) && sdkp->first_scan)
+
+	if (!sdkp->first_scan)
+		goto out;
+
+	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");
+	}
 
  out:
 	kfree(buffer);
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 4933e7daf17d..7251434100e6 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -259,7 +259,7 @@ static inline blk_status_t sd_zbc_setup_zone_mgmt_cmnd(struct scsi_cmnd *cmd,
 static inline unsigned int sd_zbc_complete(struct scsi_cmnd *cmd,
 			unsigned int good_bytes, struct scsi_sense_hdr *sshdr)
 {
-	return 0;
+	return good_bytes;
 }
 
 static inline blk_status_t sd_zbc_prepare_zone_append(struct scsi_cmnd *cmd,
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 0e94ff056bff..a739456dea02 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -667,7 +667,11 @@ int sd_zbc_revalidate_zones(struct scsi_disk *sdkp)
 	u32 max_append;
 	int ret = 0;
 
-	if (!sd_is_zoned(sdkp))
+	/*
+	 * There is nothing to do for regular disks, including host-aware disks
+	 * that have partitions.
+	 */
+	if (!blk_queue_is_zoned(q))
 		return 0;
 
 	/*