bdev/zone: add support for max active zones

The NVMe Zoned Namespace Command Set Specification has, in addition to a
Max Open Resources limit, a Max Active Resources limit.

An active resource is defined as zone being in zone state implicit open,
explicit open, or closed.

Create a function spdk_bdev_get_max_active_zones() in the generic SPDK
zone layer, so that this limit can be exposed to the user.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Change-Id: I6f61fc45e1dc38689dc54d5649c35fa9b91dbdfc
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/6908
Community-CI: Broadcom CI
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

include/spdk/bdev_module.h

@@ -366,6 +366,11 @@ struct spdk_bdev {
 	 */
 	uint32_t max_open_zones;
 
+	/**
+	 * Maximum number of active zones.
+	 */
+	uint32_t max_active_zones;
+
 	/**
 	 * Optimal number of open zones.
 	 */

include/spdk/bdev_zone.h

@@ -96,6 +96,20 @@ uint64_t spdk_bdev_get_zone_size(const struct spdk_bdev *bdev);
  */
 uint32_t spdk_bdev_get_max_open_zones(const struct spdk_bdev *bdev);
 
+/**
+ * Get device maximum number of active zones.
+ *
+ * An active zone is defined as a zone being in zone state
+ * SPDK_BDEV_ZONE_STATE_IMP_OPEN, SPDK_BDEV_ZONE_STATE_EXP_OPEN or
+ * SPDK_BDEV_ZONE_STATE_CLOSED.
+ *
+ * If this value is 0, there is no limit.
+ *
+ * \param bdev Block device to query.
+ * \return Maximum number of active zones for this zoned device.
+ */
+uint32_t spdk_bdev_get_max_active_zones(const struct spdk_bdev *bdev);
+
 /**
  * Get device optimal number of open zones.
  *

lib/bdev/bdev_zone.c

@@ -50,6 +50,12 @@ spdk_bdev_get_max_open_zones(const struct spdk_bdev *bdev)
 	return bdev->max_open_zones;
 }
 
+uint32_t
+spdk_bdev_get_max_active_zones(const struct spdk_bdev *bdev)
+{
+	return bdev->max_active_zones;
+}
+
 uint32_t
 spdk_bdev_get_optimal_open_zones(const struct spdk_bdev *bdev)
 {

lib/bdev/spdk_bdev.map

@@ -144,6 +144,7 @@
 	# Public functions in bdev_zone.h
 	spdk_bdev_get_zone_size;
 	spdk_bdev_get_max_open_zones;
+	spdk_bdev_get_max_active_zones;
 	spdk_bdev_get_optimal_open_zones;
 	spdk_bdev_get_zone_info;
 	spdk_bdev_zone_management;

test/unit/lib/bdev/bdev_zone.c/bdev_zone_ut.c

@@ -266,6 +266,18 @@ test_get_max_open_zones(void)
 	CU_ASSERT(get_max_open_zones == 8192);
 }
 
+static void
+test_get_max_active_zones(void)
+{
+	struct spdk_bdev bdev = {};
+	uint32_t get_max_active_zones;
+
+	bdev.max_active_zones = 9216;
+
+	get_max_active_zones = spdk_bdev_get_max_active_zones(&bdev);
+	CU_ASSERT(get_max_active_zones == 9216);
+}
+
 static void
 test_get_optimal_open_zones(void)
 {
@@ -295,6 +307,7 @@ test_zone_get_operation(void)
 {
 	test_get_zone_size();
 	test_get_max_open_zones();
+	test_get_max_active_zones();
 	test_get_optimal_open_zones();
 }