nvme: prepare for fault injection into admin commands

Currenlty fault injection support for nvme only enables to inject errors
into the commands submitted to I/O queues.

In preparation for fault injection into the admin commands, this makes
the helper functions independent of struct nvme_ns.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/core.c

@@ -3336,7 +3336,7 @@ static int nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	device_add_disk(ctrl->device, ns->disk, nvme_ns_id_attr_groups);
 
 	nvme_mpath_add_disk(ns, id);
-	nvme_fault_inject_init(ns);
+	nvme_fault_inject_init(&ns->fault_inject, ns->disk->disk_name);
 	kfree(id);
 
 	return 0;
@@ -3361,7 +3361,7 @@ static void nvme_ns_remove(struct nvme_ns *ns)
 	if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags))
 		return;
 
-	nvme_fault_inject_fini(ns);
+	nvme_fault_inject_fini(&ns->fault_inject);
 
 	mutex_lock(&ns->ctrl->subsys->lock);
 	list_del_rcu(&ns->siblings);

drivers/nvme/host/fault_inject.c

@@ -15,11 +15,10 @@ static DECLARE_FAULT_ATTR(fail_default_attr);
 static char *fail_request;
 module_param(fail_request, charp, 0000);
 
-void nvme_fault_inject_init(struct nvme_ns *ns)
+void nvme_fault_inject_init(struct nvme_fault_inject *fault_inj,
+			    const char *dev_name)
 {
 	struct dentry *dir, *parent;
-	char *name = ns->disk->disk_name;
-	struct nvme_fault_inject *fault_inj = &ns->fault_inject;
 	struct fault_attr *attr = &fault_inj->attr;
 
 	/* set default fault injection attribute */
@@ -27,20 +26,20 @@ void nvme_fault_inject_init(struct nvme_ns *ns)
 		setup_fault_attr(&fail_default_attr, fail_request);
 
 	/* create debugfs directory and attribute */
-	parent = debugfs_create_dir(name, NULL);
+	parent = debugfs_create_dir(dev_name, NULL);
 	if (!parent) {
-		pr_warn("%s: failed to create debugfs directory\n", name);
+		pr_warn("%s: failed to create debugfs directory\n", dev_name);
 		return;
 	}
 
 	*attr = fail_default_attr;
 	dir = fault_create_debugfs_attr("fault_inject", parent, attr);
 	if (IS_ERR(dir)) {
-		pr_warn("%s: failed to create debugfs attr\n", name);
+		pr_warn("%s: failed to create debugfs attr\n", dev_name);
 		debugfs_remove_recursive(parent);
 		return;
 	}
-	ns->fault_inject.parent = parent;
+	fault_inj->parent = parent;
 
 	/* create debugfs for status code and dont_retry */
 	fault_inj->status = NVME_SC_INVALID_OPCODE;
@@ -49,29 +48,34 @@ void nvme_fault_inject_init(struct nvme_ns *ns)
 	debugfs_create_bool("dont_retry", 0600, dir, &fault_inj->dont_retry);
 }
 
-void nvme_fault_inject_fini(struct nvme_ns *ns)
+void nvme_fault_inject_fini(struct nvme_fault_inject *fault_inject)
 {
 	/* remove debugfs directories */
-	debugfs_remove_recursive(ns->fault_inject.parent);
+	debugfs_remove_recursive(fault_inject->parent);
 }
 
 void nvme_should_fail(struct request *req)
 {
 	struct gendisk *disk = req->rq_disk;
-	struct nvme_ns *ns = NULL;
+	struct nvme_fault_inject *fault_inject = NULL;
 	u16 status;
 
 	/*
 	 * make sure this request is coming from a valid namespace
 	 */
-	if (!disk)
-		return;
+	if (disk) {
+		struct nvme_ns *ns = disk->private_data;
 
-	ns = disk->private_data;
-	if (ns && should_fail(&ns->fault_inject.attr, 1)) {
+		if (ns)
+			fault_inject = &ns->fault_inject;
+		else
+			WARN_ONCE(1, "No namespace found for request\n");
+	}
+
+	if (fault_inject && should_fail(&fault_inject->attr, 1)) {
 		/* inject status code and DNR bit */
-		status = ns->fault_inject.status;
-		if (ns->fault_inject.dont_retry)
+		status = fault_inject->status;
+		if (fault_inject->dont_retry)
 			status |= NVME_SC_DNR;
 		nvme_req(req)->status =	status;
 	}

drivers/nvme/host/nvme.h

@@ -146,6 +146,15 @@ enum nvme_ctrl_state {
 	NVME_CTRL_DEAD,
 };
 
+struct nvme_fault_inject {
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+	struct fault_attr attr;
+	struct dentry *parent;
+	bool dont_retry;	/* DNR, do not retry */
+	u16 status;		/* status code */
+#endif
+};
+
 struct nvme_ctrl {
 	bool comp_seen;
 	enum nvme_ctrl_state state;
@@ -313,15 +322,6 @@ struct nvme_ns_head {
 #endif
 };
 
-#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
-struct nvme_fault_inject {
-	struct fault_attr attr;
-	struct dentry *parent;
-	bool dont_retry;	/* DNR, do not retry */
-	u16 status;		/* status code */
-};
-#endif
-
 struct nvme_ns {
 	struct list_head list;
 
@@ -349,9 +349,7 @@ struct nvme_ns {
 #define NVME_NS_ANA_PENDING	2
 	u16 noiob;
 
-#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
 	struct nvme_fault_inject fault_inject;
-#endif
 
 };
 
@@ -372,12 +370,18 @@ struct nvme_ctrl_ops {
 };
 
 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
-void nvme_fault_inject_init(struct nvme_ns *ns);
-void nvme_fault_inject_fini(struct nvme_ns *ns);
+void nvme_fault_inject_init(struct nvme_fault_inject *fault_inj,
+			    const char *dev_name);
+void nvme_fault_inject_fini(struct nvme_fault_inject *fault_inject);
 void nvme_should_fail(struct request *req);
 #else
-static inline void nvme_fault_inject_init(struct nvme_ns *ns) {}
-static inline void nvme_fault_inject_fini(struct nvme_ns *ns) {}
+static inline void nvme_fault_inject_init(struct nvme_fault_inject *fault_inj,
+					  const char *dev_name)
+{
+}
+static inline void nvme_fault_inject_fini(struct nvme_fault_inject *fault_inj)
+{
+}
 static inline void nvme_should_fail(struct request *req) {}
 #endif