[PATCH V4 8/8] null-blk: allow REQ_OP_ZONE_RESET_ALL to configure

[Chaitanya Kulkarni <kch@nvidia.com>]

For a Zoned Block Device zone reset all is emulated if underlaying
device doesn't support REQ_OP_ZONE_RESET_ALL operation. In null_blk
Zoned mode there is no way to test zone reset all emulation present in
the block layer since we enable it by default :-

blkdev_zone_mgmt()
 blkdev_zone_reset_all_emulation() <---
 blkdev_zone_reset_all()

Add a module parameter zone_reset_all to enable or disable
REQ_OP_ZONE_RESET_ALL, enable it by default to retain the existing
behaviour.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
---
 drivers/block/null_blk/main.c     | 9 ++++++++-
 drivers/block/null_blk/null_blk.h | 1 +
 drivers/block/null_blk/zoned.c    | 3 ++-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 8b7f42024f14..5dc69f42b46c 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -260,6 +260,10 @@ static unsigned int g_zone_max_active;
 module_param_named(zone_max_active, g_zone_max_active, uint, 0444);
 MODULE_PARM_DESC(zone_max_active, "Maximum number of active zones when block device is zoned. Default: 0 (no limit)");
 
+static bool g_zone_reset_all = true;
+module_param_named(zone_reset_all, g_zone_reset_all, bool, 0444);
+MODULE_PARM_DESC(zone_reset_all, "Allow REQ_OP_ZONE_RESET_ALL. Default: true");
+
 static struct nullb_device *null_alloc_dev(void);
 static void null_free_dev(struct nullb_device *dev);
 static void null_del_dev(struct nullb *nullb);
@@ -446,6 +450,7 @@ NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL);
 NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL);
 NULLB_DEVICE_ATTR(zone_max_open, uint, NULL);
 NULLB_DEVICE_ATTR(zone_max_active, uint, NULL);
+NULLB_DEVICE_ATTR(zone_reset_all, bool, NULL);
 NULLB_DEVICE_ATTR(virt_boundary, bool, NULL);
 NULLB_DEVICE_ATTR(no_sched, bool, NULL);
 NULLB_DEVICE_ATTR(shared_tag_bitmap, bool, NULL);
@@ -574,6 +579,7 @@ static struct configfs_attribute *nullb_device_attrs[] = {
 	&nullb_device_attr_zone_nr_conv,
 	&nullb_device_attr_zone_max_open,
 	&nullb_device_attr_zone_max_active,
+	&nullb_device_attr_zone_reset_all,
 	&nullb_device_attr_virt_boundary,
 	&nullb_device_attr_no_sched,
 	&nullb_device_attr_shared_tag_bitmap,
@@ -639,7 +645,7 @@ static ssize_t memb_group_features_show(struct config_item *item, char *page)
 			"poll_queues,power,queue_mode,shared_tag_bitmap,size,"
 			"submit_queues,use_per_node_hctx,virt_boundary,zoned,"
 			"zone_capacity,zone_max_active,zone_max_open,"
-			"zone_nr_conv,zone_size,write_zeroes\n");
+			"zone_nr_conv,zone_size,zone_reset_all,write_zeroes\n");
 }
 
 CONFIGFS_ATTR_RO(memb_group_, features);
@@ -715,6 +721,7 @@ static struct nullb_device *null_alloc_dev(void)
 	dev->zone_nr_conv = g_zone_nr_conv;
 	dev->zone_max_open = g_zone_max_open;
 	dev->zone_max_active = g_zone_max_active;
+	dev->zone_reset_all = g_zone_reset_all;
 	dev->virt_boundary = g_virt_boundary;
 	dev->no_sched = g_no_sched;
 	dev->shared_tag_bitmap = g_shared_tag_bitmap;
diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/null_blk.h
index e692c2a7369e..e7efe8de4ebf 100644
--- a/drivers/block/null_blk/null_blk.h
+++ b/drivers/block/null_blk/null_blk.h
@@ -115,6 +115,7 @@ struct nullb_device {
 	bool discard; /* if support discard */
 	bool write_zeroes; /* if support write_zeroes */
 	bool zoned; /* if device is zoned */
+	bool zone_reset_all; /* if support REQ_OP_ZONE_RESET_ALL */
 	bool virt_boundary; /* virtual boundary on/off for the device */
 	bool no_sched; /* no IO scheduler for the device */
 	bool shared_tag_bitmap; /* use hostwide shared tags */
diff --git a/drivers/block/null_blk/zoned.c b/drivers/block/null_blk/zoned.c
index 55a69e48ef8b..7310d1c3f9ec 100644
--- a/drivers/block/null_blk/zoned.c
+++ b/drivers/block/null_blk/zoned.c
@@ -160,7 +160,8 @@ int null_register_zoned_dev(struct nullb *nullb)
 	struct request_queue *q = nullb->q;
 
 	disk_set_zoned(nullb->disk, BLK_ZONED_HM);
-	blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
+	if (dev->zone_reset_all)
+		blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
 	blk_queue_required_elevator_features(q, ELEVATOR_F_ZBD_SEQ_WRITE);
 
 	if (queue_is_mq(q)) {
-- 
2.29.0