[PATCH v3 0/2] Fix handling of host-aware ZBC disks

[PATCH v3 0/2] Fix handling of host-aware ZBC disks

[Damien Le Moal]

Martin,

Two patches for this cycle (with a cc stable) to fix handling of
host-aware ZBC disks that have partitions, that is, used as regular
disks.

The first patch fixes host-aware disk initialization and command
completion processing. It also enables the use of host-aware disks as
regular disks when CONFIG_BLK_DEV_ZONED is disabled.

The second patch fixes the CONFIG_BLK_DEV_ZONED enabled configuration
so that zone append emulation is not initialized for host-aware disks
with partitions/used as regular disks. While at it, this patch also
removes a problem with sd_zbc_init_disk() error handling in
sd_revalidate_disk() by moving this function execution inside
sd_zbc_revalidate_zones().

Borislav tested the previous version of this series and confirmed that
it solves his problem (thanks Borislav !)

Changes from v2:
* Introduce blk_queue_set_zoned() helper function

Changes from v1:
* Rebased on rc5
* Use "if (IS_DEFINED())" instead of #ifdef in patch 1

Damien Le Moal (2):
  scsi: Fix handling of host-aware ZBC disks
  scsi: Fix ZBC disk initialization

 block/blk-settings.c   | 46 +++++++++++++++++++++++++++++
 drivers/scsi/sd.c      | 34 ++++++++++++----------
 drivers/scsi/sd.h      |  8 +----
 drivers/scsi/sd_zbc.c  | 66 +++++++++++++++++++++++++-----------------
 include/linux/blkdev.h |  2 ++
 5 files changed, 107 insertions(+), 49 deletions(-)

-- 
2.26.2

[PATCH v3 1/2] scsi: Fix handling of host-aware ZBC disks

[Damien Le Moal]

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.

Reported-by: Borislav Petkov <bp@alien8.de>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Fixes: b72053072c0b ("block: allow partitions on host aware zone devices")
Cc: <stable@vger.kernel.org>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 block/blk-settings.c   | 46 ++++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/sd.c      | 30 ++++++++++++++++-----------
 drivers/scsi/sd.h      |  2 +-
 drivers/scsi/sd_zbc.c  |  6 +++++-
 include/linux/blkdev.h |  2 ++
 5 files changed, 72 insertions(+), 14 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index 76a7e03bcd6c..34b721a2743a 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -801,6 +801,52 @@ bool blk_queue_can_use_dma_map_merging(struct request_queue *q,
 }
 EXPORT_SYMBOL_GPL(blk_queue_can_use_dma_map_merging);
 
+/**
+ * blk_queue_set_zoned - configure a disk queue zoned model.
+ * @disk:	the gendisk of the queue to configure
+ * @model:	the zoned model to set
+ *
+ * Set the zoned model of the request queue of @disk according to @model.
+ * When @model is BLK_ZONED_HM (host managed), this should be called only
+ * if zoned block device support is enabled (CONFIG_BLK_DEV_ZONED option).
+ * If @model specifies BLK_ZONED_HA (host aware), the effective model used
+ * depends on CONFIG_BLK_DEV_ZONED settings and on the existence of partitions
+ * on the disk.
+ */
+void blk_queue_set_zoned(struct gendisk *disk, enum blk_zoned_model model)
+{
+	switch (model) {
+	case BLK_ZONED_HM:
+		/*
+		 * Host managed devices are supported only if
+		 * CONFIG_BLK_DEV_ZONED is enabled.
+		 */
+		WARN_ON_ONCE(!IS_ENABLED(CONFIG_BLK_DEV_ZONED));
+		break;
+	case BLK_ZONED_HA:
+		/*
+		 * Host aware devices can be treated either as regular block
+		 * devices (similar to drive managed devices) or as zoned block
+		 * devices to take advantage of the zone command set, similarly
+		 * to host managed devices. We try the latter if there are no
+		 * partitions and zoned block device support is enabled, else
+		 * we do nothing special as far as the block layer is concerned.
+		 */
+		if (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) ||
+		    disk_has_partitions(disk))
+			model = BLK_ZONED_NONE;
+		break;
+	case BLK_ZONED_NONE:
+	default:
+		if (WARN_ON_ONCE(model != BLK_ZONED_NONE))
+			model = BLK_ZONED_NONE;
+		break;
+	}
+
+	disk->queue->limits.zoned = model;
+}
+EXPORT_SYMBOL_GPL(blk_queue_set_zoned);
+
 static int __init blk_settings_init(void)
 {
 	blk_max_low_pfn = max_low_pfn - 1;
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;
 
 	/*
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index bb5636cc17b9..868e11face00 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -352,6 +352,8 @@ struct queue_limits {
 typedef int (*report_zones_cb)(struct blk_zone *zone, unsigned int idx,
 			       void *data);
 
+void blk_queue_set_zoned(struct gendisk *disk, enum blk_zoned_model model);
+
 #ifdef CONFIG_BLK_DEV_ZONED
 
 #define BLK_ALL_ZONES  ((unsigned int)-1)
-- 
2.26.2

[PATCH v3 2/2] scsi: Fix ZBC disk initialization

[Damien Le Moal]

Make sure to call sd_zbc_init_disk() when the sdkp->zoned field is
known, that is, once sd_read_block_characteristics() is executed in
sd_revalidate_disk(), so that host-aware disks also get initialized.
To do so, move sd_zbc_init_disk() call in sd_zbc_revalidate_zones() and
make sure to execute it for all zoned disks, including for host-aware
disks used as regular disks as these disk zoned model may be changed
back to BLK_ZONED_HA when partitions are deleted.

Reported-by: Borislav Petkov <bp@alien8.de>
Fixes: 5795eb443060 ("scsi: sd_zbc: emulate ZONE_APPEND commands")
Cc: <stable@vger.kernel.org> # v5.8+
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Tested-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 drivers/scsi/sd.c     |  4 ---
 drivers/scsi/sd.h     |  6 -----
 drivers/scsi/sd_zbc.c | 60 +++++++++++++++++++++++++------------------
 3 files changed, 35 insertions(+), 35 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 06286b6aeaec..16503e22691e 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3410,10 +3410,6 @@ static int sd_probe(struct device *dev)
 	sdkp->first_scan = 1;
 	sdkp->max_medium_access_timeouts = SD_MAX_MEDIUM_TIMEOUTS;
 
-	error = sd_zbc_init_disk(sdkp);
-	if (error)
-		goto out_free_index;
-
 	sd_revalidate_disk(gd);
 
 	gd->flags = GENHD_FL_EXT_DEVT;
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 7251434100e6..a3aad608bc38 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -215,7 +215,6 @@ static inline int sd_is_zoned(struct scsi_disk *sdkp)
 
 #ifdef CONFIG_BLK_DEV_ZONED
 
-int sd_zbc_init_disk(struct scsi_disk *sdkp);
 void sd_zbc_release_disk(struct scsi_disk *sdkp);
 int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buffer);
 int sd_zbc_revalidate_zones(struct scsi_disk *sdkp);
@@ -231,11 +230,6 @@ blk_status_t sd_zbc_prepare_zone_append(struct scsi_cmnd *cmd, sector_t *lba,
 
 #else /* CONFIG_BLK_DEV_ZONED */
 
-static inline int sd_zbc_init_disk(struct scsi_disk *sdkp)
-{
-	return 0;
-}
-
 static inline void sd_zbc_release_disk(struct scsi_disk *sdkp) {}
 
 static inline int sd_zbc_read_zones(struct scsi_disk *sdkp,
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index a739456dea02..cf07b7f93579 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -651,6 +651,28 @@ static void sd_zbc_print_zones(struct scsi_disk *sdkp)
 			  sdkp->zone_blocks);
 }
 
+static int sd_zbc_init_disk(struct scsi_disk *sdkp)
+{
+	sdkp->zones_wp_offset = NULL;
+	spin_lock_init(&sdkp->zones_wp_offset_lock);
+	sdkp->rev_wp_offset = NULL;
+	mutex_init(&sdkp->rev_mutex);
+	INIT_WORK(&sdkp->zone_wp_offset_work, sd_zbc_update_wp_offset_workfn);
+	sdkp->zone_wp_update_buf = kzalloc(SD_BUF_SIZE, GFP_KERNEL);
+	if (!sdkp->zone_wp_update_buf)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void sd_zbc_release_disk(struct scsi_disk *sdkp)
+{
+	kvfree(sdkp->zones_wp_offset);
+	sdkp->zones_wp_offset = NULL;
+	kfree(sdkp->zone_wp_update_buf);
+	sdkp->zone_wp_update_buf = NULL;
+}
+
 static void sd_zbc_revalidate_zones_cb(struct gendisk *disk)
 {
 	struct scsi_disk *sdkp = scsi_disk(disk);
@@ -667,6 +689,19 @@ int sd_zbc_revalidate_zones(struct scsi_disk *sdkp)
 	u32 max_append;
 	int ret = 0;
 
+	/*
+	 * For all zoned disks, initialize zone append emulation data if not
+	 * already done. This is necessary also for host-aware disks used as
+	 * regular disks due to the presence of partitions as these partitions
+	 * may be deleted and the disk zoned model changed back from
+	 * BLK_ZONED_NONE to BLK_ZONED_HA.
+	 */
+	if (sd_is_zoned(sdkp) && !sdkp->zone_wp_update_buf) {
+		ret = sd_zbc_init_disk(sdkp);
+		if (ret)
+			return ret;
+	}
+
 	/*
 	 * There is nothing to do for regular disks, including host-aware disks
 	 * that have partitions.
@@ -768,28 +803,3 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
 
 	return ret;
 }
-
-int sd_zbc_init_disk(struct scsi_disk *sdkp)
-{
-	if (!sd_is_zoned(sdkp))
-		return 0;
-
-	sdkp->zones_wp_offset = NULL;
-	spin_lock_init(&sdkp->zones_wp_offset_lock);
-	sdkp->rev_wp_offset = NULL;
-	mutex_init(&sdkp->rev_mutex);
-	INIT_WORK(&sdkp->zone_wp_offset_work, sd_zbc_update_wp_offset_workfn);
-	sdkp->zone_wp_update_buf = kzalloc(SD_BUF_SIZE, GFP_KERNEL);
-	if (!sdkp->zone_wp_update_buf)
-		return -ENOMEM;
-
-	return 0;
-}
-
-void sd_zbc_release_disk(struct scsi_disk *sdkp)
-{
-	kvfree(sdkp->zones_wp_offset);
-	sdkp->zones_wp_offset = NULL;
-	kfree(sdkp->zone_wp_update_buf);
-	sdkp->zone_wp_update_buf = NULL;
-}
-- 
2.26.2

Re: [PATCH v3 1/2] scsi: Fix handling of host-aware ZBC disks

[Christoph Hellwig]

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH v3 2/2] scsi: Fix ZBC disk initialization

[Christoph Hellwig]

On Tue, Sep 15, 2020 at 04:33:47PM +0900, Damien Le Moal wrote:
> Make sure to call sd_zbc_init_disk() when the sdkp->zoned field is
> known, that is, once sd_read_block_characteristics() is executed in
> sd_revalidate_disk(), so that host-aware disks also get initialized.
> To do so, move sd_zbc_init_disk() call in sd_zbc_revalidate_zones() and
> make sure to execute it for all zoned disks, including for host-aware
> disks used as regular disks as these disk zoned model may be changed
> back to BLK_ZONED_HA when partitions are deleted.
> 
> Reported-by: Borislav Petkov <bp@alien8.de>
> Fixes: 5795eb443060 ("scsi: sd_zbc: emulate ZONE_APPEND commands")
> Cc: <stable@vger.kernel.org> # v5.8+
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> Tested-by: Borislav Petkov <bp@suse.de>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH v3 1/2] scsi: Fix handling of host-aware ZBC disks

[Johannes Thumshirn]

Whoops forgot to reply,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Re: [PATCH v3 0/2] Fix handling of host-aware ZBC disks

[Martin K. Petersen]

Damien,

> The first patch fixes host-aware disk initialization and command
> completion processing. It also enables the use of host-aware disks as
> regular disks when CONFIG_BLK_DEV_ZONED is disabled.
>
> The second patch fixes the CONFIG_BLK_DEV_ZONED enabled configuration
> so that zone append emulation is not initialized for host-aware disks
> with partitions/used as regular disks. While at it, this patch also
> removes a problem with sd_zbc_init_disk() error handling in
> sd_revalidate_disk() by moving this function execution inside
> sd_zbc_revalidate_zones().

Applied to 5.9/scsi-fixes, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH v3 1/2] scsi: Fix handling of host-aware ZBC disks

[Sasha Levin]

Hi

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag
fixing commit: b72053072c0b ("block: allow partitions on host aware zone devices").

The bot has tested the following trees: v5.8.9.

v5.8.9: Failed to apply! Possible dependencies:
    a3d8a2573687 ("scsi: sd_zbc: Improve zone revalidation")


NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?

-- 
Thanks
Sasha

Re: [PATCH v3 1/2] scsi: Fix handling of host-aware ZBC disks

[Damien Le Moal]

On 2020/09/18 0:53, Sasha Levin wrote:
> Hi
> 
> [This is an automated email]
> 
> This commit has been processed because it contains a "Fixes:" tag
> fixing commit: b72053072c0b ("block: allow partitions on host aware zone devices").
> 
> The bot has tested the following trees: v5.8.9.
> 
> v5.8.9: Failed to apply! Possible dependencies:
>     a3d8a2573687 ("scsi: sd_zbc: Improve zone revalidation")
> 
> 
> NOTE: The patch will not be queued to stable trees until it is upstream.
> 
> How should we proceed with this patch?
> 

Usually, I wait for Greg's bots to ping me and then I send a fixed up backported
patch for stable. Would that work ? I can backport now if needed.

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v3 1/2] scsi: Fix handling of host-aware ZBC disks

[Greg KH]

On Thu, Sep 17, 2020 at 11:50:44PM +0000, Damien Le Moal wrote:
> On 2020/09/18 0:53, Sasha Levin wrote:
> > Hi
> > 
> > [This is an automated email]
> > 
> > This commit has been processed because it contains a "Fixes:" tag
> > fixing commit: b72053072c0b ("block: allow partitions on host aware zone devices").
> > 
> > The bot has tested the following trees: v5.8.9.
> > 
> > v5.8.9: Failed to apply! Possible dependencies:
> >     a3d8a2573687 ("scsi: sd_zbc: Improve zone revalidation")
> > 
> > 
> > NOTE: The patch will not be queued to stable trees until it is upstream.
> > 
> > How should we proceed with this patch?
> > 
> 
> Usually, I wait for Greg's bots to ping me and then I send a fixed up backported
> patch for stable. Would that work ? I can backport now if needed.

That works, no worries, thanks.

greg k-h