[1/2] scsi: Fix handling of host-aware ZBC disks

Commit Message

Damien Le Moal Sept. 13, 2020, 6:03 a.m. UTC

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, 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.

Reported-by: Borislav Petkov <[e-mail]>
Fixes: b72053072c0b ("block: allow partitions on host aware zone devices")
Cc: <[e-mail]>
Signed-off-by: Damien Le Moal <[e-mail]>
---
 drivers/scsi/sd.c     | 22 ++++++++++++++++++----
 drivers/scsi/sd.h     |  2 +-
 drivers/scsi/sd_zbc.c |  6 +++++-
 3 files changed, 24 insertions(+), 6 deletions(-)

Comments

Borislav Petkov Sept. 13, 2020, 7:05 a.m. UTC | #1

On Sun, Sep 13, 2020 at 03:03:03PM +0900, Damien Le Moal wrote:
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 95018e650f2d..7f0371185a45 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -2968,22 +2968,36 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp)
>  	} else {
>  		sdkp->zoned = (buffer[8] >> 4) & 3;
>  		if (sdkp->zoned == 1 && !disk_has_partitions(sdkp->disk)) {
> +#ifdef CONFIG_BLK_DEV_ZONED

You could make that

		if (IS_ENABLED(CONFIG_BLK_DEV_ZONED))

and get rid of the ugly ifdeffery.

Just a nitpick anyway.

Johannes Thumshirn Sept. 13, 2020, 8:03 a.m. UTC | #2

With Boris' comment worked in,
Reviewed-by: Johannes Thumshirn <[e-mail]>

Patch

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 95018e650f2d..7f0371185a45 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2968,22 +2968,36 @@  static void sd_read_block_characteristics(struct scsi_disk *sdkp)
 	} else {
 		sdkp->zoned = (buffer[8] >> 4) & 3;
 		if (sdkp->zoned == 1 && !disk_has_partitions(sdkp->disk)) {
+#ifdef CONFIG_BLK_DEV_ZONED
 			/* Host-aware */
 			q->limits.zoned = BLK_ZONED_HA;
+#else
+			/* Host-aware drive is treated as a regular disk */
+			q->limits.zoned = BLK_ZONED_NONE;
+#endif
 		} 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");
 		}
 	}
-	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;
 
 	/*