bdev/zone: add support for get zone id

In the bdev-zone API, there are a few functions that takes a zone_id:
spdk_bdev_get_zone_info(), spdk_bdev_zone_management(), and the
spdk_bdev_zone_append() functions.

The way a zoned application is usually written is that it starts off
by getting the zone report for all zones (zone_id will be sent in as 0),
and then the application will keep the whole zone report in memory.

Therefore, an application usually have access to the zone_id/zslba for
all zones. However, there are cases, e.g. when getting an error on write,
where the completion callback will only have the lba of the write that
failed.

Add a helper function that can be used to get the zone_id/slba for a
given lba. Having this helper in bdev-zone will avoid SPDK applications
needing to provide their own implementation for this.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Change-Id: I978335f87f7d49bc33aed81afcaa6d9f0af8a1e4
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/10180
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>

include/spdk/bdev_zone.h

@@ -92,6 +92,16 @@ uint64_t spdk_bdev_get_zone_size(const struct spdk_bdev *bdev);
  */
 uint64_t spdk_bdev_get_num_zones(const struct spdk_bdev *bdev);
 
+/**
+ * Get the first logical block of a zone (known as zone_id or zslba)
+ * for a given offset.
+ *
+ * \param bdev Block device to query.
+ * \param offset_blocks The offset, in blocks, from the start of the block device.
+ * \return The zone_id (also known as zslba) for the given offset.
+ */
+uint64_t spdk_bdev_get_zone_id(const struct spdk_bdev *bdev, uint64_t offset_blocks);
+
 /**
  * Get device maximum zone append data transfer size in logical blocks.
  *

lib/bdev/Makefile

@@ -35,7 +35,7 @@ SPDK_ROOT_DIR := $(abspath $(CURDIR)/../..)
 include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
 SO_VER := 8
-SO_MINOR := 0
+SO_MINOR := 1
 
 ifeq ($(CONFIG_VTUNE),y)
 CFLAGS += -I$(CONFIG_VTUNE_DIR)/include -I$(CONFIG_VTUNE_DIR)/sdk/src/ittnotify

lib/bdev/bdev_zone.c

@@ -35,6 +35,7 @@
 
 #include "spdk/bdev_zone.h"
 #include "spdk/bdev_module.h"
+#include "spdk/likely.h"
 
 #include "bdev_internal.h"
 
@@ -50,6 +51,22 @@ spdk_bdev_get_num_zones(const struct spdk_bdev *bdev)
 	return bdev->zone_size ? bdev->blockcnt / bdev->zone_size : 0;
 }
 
+uint64_t
+spdk_bdev_get_zone_id(const struct spdk_bdev *bdev, uint64_t offset_blocks)
+{
+	uint64_t zslba;
+
+	if (spdk_likely(spdk_u64_is_pow2(bdev->zone_size))) {
+		uint64_t zone_mask = bdev->zone_size - 1;
+		zslba = offset_blocks & ~zone_mask;
+	} else {
+		/* integer division */
+		zslba = (offset_blocks / bdev->zone_size) * bdev->zone_size;
+	}
+
+	return zslba;
+}
+
 uint32_t
 spdk_bdev_get_max_zone_append_size(const struct spdk_bdev *bdev)
 {

lib/bdev/spdk_bdev.map

@@ -149,6 +149,7 @@
 	# Public functions in bdev_zone.h
 	spdk_bdev_get_zone_size;
 	spdk_bdev_get_num_zones;
+	spdk_bdev_get_zone_id;
 	spdk_bdev_get_max_zone_append_size;
 	spdk_bdev_get_max_open_zones;
 	spdk_bdev_get_max_active_zones;

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

@@ -267,6 +267,19 @@ test_get_num_zones(void)
 	CU_ASSERT(get_num_zones == 256);
 }
 
+static void
+test_get_zone_id(void)
+{
+	struct spdk_bdev bdev = {};
+	uint64_t get_zone_id;
+
+	bdev.blockcnt = 1024 * 1024 * 1024;
+	bdev.zone_size = 1024 * 4096;
+
+	get_zone_id = spdk_bdev_get_zone_id(&bdev, 0x800032);
+	CU_ASSERT(get_zone_id == 0x800000);
+}
+
 static void
 test_get_max_zone_append_size(void)
 {
@@ -332,6 +345,7 @@ test_zone_get_operation(void)
 {
 	test_get_zone_size();
 	test_get_num_zones();
+	test_get_zone_id();
 	test_get_max_zone_append_size();
 	test_get_max_open_zones();
 	test_get_max_active_zones();