scsi: Add spdk_scsi_dev_get_first/next_lun() to traverse all LUNs

Add two public APIs spdk_scsi_dev_get_first_lun() and
spdk_scsi_dev_get_next_lun() to remove the dependency on the macro
constant SPDK_SCSI_DEV_MAX_LUN from lib/iscsi and lib/vhost.

Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Change-Id: I6546697f823fe9f4fa34e1161f5c7fa912dd2d59
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/9608
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
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: GangCao <gang.cao@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>

CHANGELOG.md

@@ -81,6 +81,11 @@ Added `spdk_nvme_ctrlr_get_opts` to retrieve the current controller options.
 
 Updated DPDK submodule to DPDK 21.08.
 
+### scsi
+
+New functions, `spdk_scsi_dev_get_first_lun` and `spdk_scsi_dev_get_next_lun`
+have been added to iterate LUNs of a SCSI device.
+
 ### util
 
 The `spdk_fd_group_add` API now takes a `name` parameter.

include/spdk/scsi.h

@@ -229,6 +229,24 @@ int spdk_scsi_dev_get_id(const struct spdk_scsi_dev *dev);
  */
 struct spdk_scsi_lun *spdk_scsi_dev_get_lun(struct spdk_scsi_dev *dev, int lun_id);
 
+/**
+ * Get the first logical unit of the given SCSI device.
+ *
+ * \param dev SCSI device.
+ *
+ * \return the first logical unit on success, or NULL if there is no logical unit.
+ */
+struct spdk_scsi_lun *spdk_scsi_dev_get_first_lun(struct spdk_scsi_dev *dev);
+
+/**
+ * Get the next logical unit of a SCSI device.
+ *
+ * \param lun Previous logical unit.
+ *
+ * \return the next logical unit of a SCSI device, or NULL if the prev_lun was the last.
+ */
+struct spdk_scsi_lun *spdk_scsi_dev_get_next_lun(struct spdk_scsi_lun *prev_lun);
+
 /**
  * Check whether the SCSI device has any pending task.
  *

lib/scsi/Makefile

@@ -35,7 +35,7 @@ SPDK_ROOT_DIR := $(abspath $(CURDIR)/../..)
 include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
 SO_VER := 4
-SO_MINOR := 0
+SO_MINOR := 1
 
 C_SRCS = dev.c lun.c port.c scsi.c scsi_bdev.c scsi_pr.c scsi_rpc.c task.c
 LIBNAME = scsi

lib/scsi/dev.c

@@ -436,6 +436,45 @@ spdk_scsi_dev_get_lun(struct spdk_scsi_dev *dev, int lun_id)
 	}
 }
 
+struct spdk_scsi_lun *
+spdk_scsi_dev_get_first_lun(struct spdk_scsi_dev *dev)
+{
+	struct spdk_scsi_lun *lun;
+	int lun_id;
+
+	for (lun_id = 0; lun_id < SPDK_SCSI_DEV_MAX_LUN; lun_id++) {
+		lun = dev->lun[lun_id];
+		if (lun != NULL && !spdk_scsi_lun_is_removing(lun)) {
+			return lun;
+		}
+	}
+
+	return NULL;
+}
+
+struct spdk_scsi_lun *
+spdk_scsi_dev_get_next_lun(struct spdk_scsi_lun *prev_lun)
+{
+	struct spdk_scsi_dev *dev;
+	struct spdk_scsi_lun *lun;
+	int lun_id;
+
+	if (prev_lun == NULL) {
+		return NULL;
+	}
+
+	dev = prev_lun->dev;
+
+	for (lun_id = prev_lun->id + 1; lun_id < SPDK_SCSI_DEV_MAX_LUN; lun_id++) {
+		lun = dev->lun[lun_id];
+		if (lun != NULL && !spdk_scsi_lun_is_removing(lun)) {
+			return lun;
+		}
+	}
+
+	return NULL;
+}
+
 bool
 spdk_scsi_dev_has_pending_tasks(const struct spdk_scsi_dev *dev,
 				const struct spdk_scsi_port *initiator_port)

lib/scsi/spdk_scsi.map

@@ -11,6 +11,8 @@
 	spdk_scsi_dev_get_name;
 	spdk_scsi_dev_get_id;
 	spdk_scsi_dev_get_lun;
+	spdk_scsi_dev_get_first_lun;
+	spdk_scsi_dev_get_next_lun;
 	spdk_scsi_dev_has_pending_tasks;
 	spdk_scsi_dev_destruct;
 	spdk_scsi_dev_queue_mgmt_task;

test/unit/lib/scsi/dev.c/dev_ut.c

@@ -49,6 +49,8 @@ DEFINE_STUB(spdk_scsi_lun_is_removing, bool,
 static char *g_bdev_names[] = {
 	"malloc0",
 	"malloc1",
+	"malloc2",
+	"malloc4",
 };
 
 static struct spdk_scsi_port *g_initiator_port_with_pending_tasks = NULL;
@@ -543,7 +545,7 @@ dev_add_lun_bdev_not_found(void)
 	int rc;
 	struct spdk_scsi_dev dev = {0};
 
-	rc = spdk_scsi_dev_add_lun(&dev, "malloc2", 0, NULL, NULL);
+	rc = spdk_scsi_dev_add_lun(&dev, "malloc3", 0, NULL, NULL);
 
 	SPDK_CU_ASSERT_FATAL(dev.lun[0] == NULL);
 	CU_ASSERT_NOT_EQUAL(rc, 0);
@@ -619,6 +621,36 @@ dev_check_pending_tasks(void)
 	CU_ASSERT(spdk_scsi_dev_has_pending_tasks(&dev, &initiator_port) == true);
 }
 
+static void
+dev_iterate_luns(void)
+{
+	struct spdk_scsi_dev *dev;
+	struct spdk_scsi_lun *lun;
+	const char *bdev_name_list[3] = {"malloc0", "malloc2", "malloc4"};
+	int lun_id_list[3] = {0, 2, 4};
+
+	dev = spdk_scsi_dev_construct("Name", bdev_name_list, lun_id_list, 3,
+				      SPDK_SPC_PROTOCOL_IDENTIFIER_ISCSI, NULL, NULL);
+
+	/* Successfully constructs and returns a dev */
+	CU_ASSERT_TRUE(dev != NULL);
+
+	lun = spdk_scsi_dev_get_first_lun(dev);
+	CU_ASSERT(lun != NULL);
+	CU_ASSERT(lun->id == 0);
+	lun = spdk_scsi_dev_get_next_lun(lun);
+	CU_ASSERT(lun != NULL);
+	CU_ASSERT(lun->id == 2);
+	lun = spdk_scsi_dev_get_next_lun(lun);
+	CU_ASSERT(lun != NULL);
+	CU_ASSERT(lun->id == 4);
+	lun = spdk_scsi_dev_get_next_lun(lun);
+	CU_ASSERT(lun == NULL);
+
+	/* free the dev */
+	spdk_scsi_dev_destruct(dev, NULL, NULL);
+}
+
 int
 main(int argc, char **argv)
 {
@@ -657,6 +689,7 @@ main(int argc, char **argv)
 	CU_ADD_TEST(suite, dev_add_lun_success1);
 	CU_ADD_TEST(suite, dev_add_lun_success2);
 	CU_ADD_TEST(suite, dev_check_pending_tasks);
+	CU_ADD_TEST(suite, dev_iterate_luns);
 
 	CU_basic_set_mode(CU_BRM_VERBOSE);
 	CU_basic_run_tests();