nvme: Fix disk names when not using nvme multipath

index 127a9cbf3314..3dcb0ebe9575 100644
@@ -366,6 +366,7 @@ static void nvme_free_ns(struct kref *kref)
 		nvme_nvm_unregister(ns);
 
 	put_disk(ns->disk);
+	ida_simple_remove(&ns->head->subsys->ns_ida, ns->instance);
 	nvme_put_ns_head(ns->head);
 	nvme_put_ctrl(ns->ctrl);
 	kfree(ns);

@@ -2905,6 +2906,10 @@ static int nvme_init_ns_head(struct nvme_ns *ns, unsigned nsid,
 	list_add_tail(&ns->siblings, &head->list);
 	ns->head = head;
 
+	ns->instance = ida_simple_get(&head->subsys->ns_ida, 1, 0, GFP_KERNEL);
+	if (ns->instance < 0)
+		ret = ns->instance;
+
 out_unlock:
 	mutex_unlock(&ctrl->subsys->lock);
 	return ret;

@@ -3013,7 +3018,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 		flags = GENHD_FL_HIDDEN;
 	} else {
 		sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
-				ns->head->instance);
+				ns->instance);
 	}
 #else
 	/*

@@ -3068,6 +3073,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	mutex_lock(&ctrl->subsys->lock);
 	list_del_rcu(&ns->siblings);
 	mutex_unlock(&ctrl->subsys->lock);
+	ida_simple_remove(&ns->head->subsys->ns_ida, ns->instance);
  out_free_id:
 	kfree(id);
  out_free_queue:

index 061fecfd44f5..334dd5311955 100644
@@ -283,6 +283,7 @@ struct nvme_ns {
 	struct kref kref;
 	struct nvme_ns_head *head;
 
+	int instance;
 	int lba_shift;
 	u16 ms;
 	u16 sgs;

index 197a6ba9700f..bfd67bc71455 100644
@@ -3001,10 +3001,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 		sprintf(disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
 				ctrl->cntlid, ns->head->instance);
 		flags = GENHD_FL_HIDDEN;
-	} else {
-		sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
-				ns->head->instance);
-	}
+	} else
 #else
 	/*
 	 * But without the multipath code enabled, multiple controller per

index 197a6ba9700f..ffca28dd2836 100644
@@ -68,6 +68,11 @@ static bool streams;
 module_param(streams, bool, 0644);
 MODULE_PARM_DESC(streams, "turn on support for Streams write directives");
 
+bool multipath = true;
+module_param(multipath, bool, 0644);
+MODULE_PARM_DESC(multipath,
+	"turn on native support for multiple controllers per subsystem");
+
 /*
  * nvme_wq - hosts nvme related works that are not reset or delete
  * nvme_reset_wq - hosts nvme reset works

@@ -2989,6 +2994,13 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 		goto out_free_id;
 	nvme_setup_streams_ns(ctrl, ns);
 	
+	/*
+	 * Without the multipath code enabled, multiple controller per subsystem
+	 * are visible as devices and thus we cannot use the subsystem instance.
+	 */
+	if (!IS_ENABLED(CONFIG_NVME_MULTIPATH) || !multipath) {
+		sprintf(disk_name, "nvme%dn%d", ctrl->instance,
+				ns->head->instance);
 #ifdef CONFIG_NVME_MULTIPATH
 	/*
 	 * If multipathing is enabled we need to always use the subsystem

@@ -2997,22 +3009,15 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	 * the multipath-aware subsystem node and those that have a single
 	 * controller and use the controller node directly.
 	 */
-	if (ns->head->disk) {
+	} else if (ns->head->disk) {
 		sprintf(disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
 				ctrl->cntlid, ns->head->instance);
 		flags = GENHD_FL_HIDDEN;
 	} else {
 		sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
 				ns->head->instance);
-	}
-#else
-	/*
-	 * But without the multipath code enabled, multiple controller per
-	 * subsystems are visible as devices and thus we cannot use the
-	 * subsystem instance.
-	 */
-	sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
 #endif
+	}
 
 	if ((ctrl->quirks & NVME_QUIRK_LIGHTNVM) && id->vs[0] == 0x1) {
 		if (nvme_nvm_register(ns, disk_name, node)) {

index 956e0b8e9c4d..3b0643d6cfc4 100644
@@ -14,11 +14,6 @@
 #include <linux/moduleparam.h>
 #include "nvme.h"
 
-static bool multipath = true;
-module_param(multipath, bool, 0644);
-MODULE_PARM_DESC(multipath,
-	"turn on native support for multiple controllers per subsystem");
-
 void nvme_failover_req(struct request *req)
 {
 	struct nvme_ns *ns = req->q->queuedata;

index cf93690b3ffc..b35b0f9f94c1 100644
@@ -32,6 +32,8 @@ extern unsigned int admin_timeout;
 #define NVME_DEFAULT_KATO	5
 #define NVME_KATO_GRACE		10
 
+extern bool multipath;
+
 extern struct workqueue_struct *nvme_wq;
 extern struct workqueue_struct *nvme_reset_wq;
 extern struct workqueue_struct *nvme_delete_wq;

index 127a9cbf3314..a3771c5729f5 100644
@@ -2998,31 +2998,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	if (nvme_init_ns_head(ns, nsid, id))
 		goto out_free_id;
 	nvme_setup_streams_ns(ctrl, ns);
-	
-#ifdef CONFIG_NVME_MULTIPATH
-	/*
-	 * If multipathing is enabled we need to always use the subsystem
-	 * instance number for numbering our devices to avoid conflicts
-	 * between subsystems that have multiple controllers and thus use
-	 * the multipath-aware subsystem node and those that have a single
-	 * controller and use the controller node directly.
-	 */
-	if (ns->head->disk) {
-		sprintf(disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
-				ctrl->cntlid, ns->head->instance);
-		flags = GENHD_FL_HIDDEN;
-	} else {
-		sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
-				ns->head->instance);
-	}
-#else
-	/*
-	 * But without the multipath code enabled, multiple controller per
-	 * subsystems are visible as devices and thus we cannot use the
-	 * subsystem instance.
-	 */
-	sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
-#endif
+	nvme_set_disk_name(disk_name, ns, ctrl, &flags);
 
 	if ((ctrl->quirks & NVME_QUIRK_LIGHTNVM) && id->vs[0] == 0x1) {
 		if (nvme_nvm_register(ns, disk_name, node)) {

index 956e0b8e9c4d..977539d0bb53 100644
@@ -15,10 +15,32 @@
 #include "nvme.h"
 
 static bool multipath = true;
-module_param(multipath, bool, 0644);
+module_param(multipath, bool, 0444);
 MODULE_PARM_DESC(multipath,
 	"turn on native support for multiple controllers per subsystem");
 
+/*
+ * If multipathing is enabled we need to always use the subsystem instance
+ * number for numbering our devices to avoid conflicts between subsystems that
+ * have multiple controllers and thus use the multipath-aware subsystem node
+ * and those that have a single controller and use the controller node
+ * directly.
+ */
+void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
+			struct nvme_ctrl *ctrl, int *flags)
+{
+	if (!multipath) {
+		nvme_simple_disk_name(disk_name, ns, ctrl);
+	} else if (ns->head->disk) {
+		sprintf(disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
+				ctrl->cntlid, ns->head->instance);
+		*flags = GENHD_FL_HIDDEN;
+	} else {
+		sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
+				ns->head->instance);
+	}
+}
+
 void nvme_failover_req(struct request *req)
 {
 	struct nvme_ns *ns = req->q->queuedata;

index 061fecfd44f5..2d4a139b00f1 100644
@@ -435,7 +435,19 @@ int nvme_get_log_ext(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
 extern const struct attribute_group nvme_ns_id_attr_group;
 extern const struct block_device_operations nvme_ns_head_ops;
 
+/*
+ * Without the multipath code enabled, multiple controller per subsystems are
+ * visible as devices and thus we cannot use the subsystem instance.
+ */
+static inline void nvme_simple_disk_name(char *disk_name, struct nvme_ns *ns,
+				         struct nvme_ctrl *ctrl)
+{
+	sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
+}
+
 #ifdef CONFIG_NVME_MULTIPATH
+void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
+			struct nvme_ctrl *ctrl, int *flags);
 void nvme_failover_req(struct request *req);
 bool nvme_req_needs_failover(struct request *req, blk_status_t error);
 void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl);

@@ -461,6 +473,12 @@ static inline void nvme_mpath_check_last_path(struct nvme_ns *ns)
 }
 
 #else
+static inline void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
+				      struct nvme_ctrl *ctrl, int *flags)
+{
+	nvme_simple_disk_name(disk_name, ns, ctrl);
+}
+
 static inline void nvme_failover_req(struct request *req)
 {
 }