nvme: lift the file open code from nvme_ctrl_get_by_path

Lift opening the file open/close code from nvme_ctrl_get_by_path into
the caller, just keeping a simple nvme_ctrl_from_file() helper.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
[hch: refactored a bit, split the bug fixes into a separate prep patch]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>

drivers/nvme/host/core.c

@@ -4668,28 +4668,13 @@ void nvme_sync_queues(struct nvme_ctrl *ctrl)
 }
 EXPORT_SYMBOL_GPL(nvme_sync_queues);
 
-struct nvme_ctrl *nvme_ctrl_get_by_path(const char *path)
+struct nvme_ctrl *nvme_ctrl_from_file(struct file *file)
 {
-	struct nvme_ctrl *ctrl;
-	struct file *f;
-
-	f = filp_open(path, O_RDWR, 0);
-	if (IS_ERR(f))
-		return ERR_CAST(f);
-
-	if (f->f_op != &nvme_dev_fops) {
-		ctrl = ERR_PTR(-EINVAL);
-		goto out_close;
-	}
-
-	ctrl = f->private_data;
-	nvme_get_ctrl(ctrl);
-
-out_close:
-	filp_close(f, NULL);
-	return ctrl;
+	if (file->f_op != &nvme_dev_fops)
+		return NULL;
+	return file->private_data;
 }
-EXPORT_SYMBOL_NS_GPL(nvme_ctrl_get_by_path, NVME_TARGET_PASSTHRU);
+EXPORT_SYMBOL_NS_GPL(nvme_ctrl_from_file, NVME_TARGET_PASSTHRU);
 
 /*
  * Check we didn't inadvertently grow the command structure sizes:

drivers/nvme/host/nvme.h

@@ -822,7 +822,7 @@ static inline void nvme_hwmon_init(struct nvme_ctrl *ctrl) { }
 u32 nvme_command_effects(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
 			 u8 opcode);
 void nvme_execute_passthru_rq(struct request *rq);
-struct nvme_ctrl *nvme_ctrl_get_by_path(const char *path);
+struct nvme_ctrl *nvme_ctrl_from_file(struct file *file);
 struct nvme_ns *nvme_find_get_ns(struct nvme_ctrl *ctrl, unsigned nsid);
 void nvme_put_ns(struct nvme_ns *ns);
 

drivers/nvme/target/passthru.c

@@ -474,6 +474,7 @@ u16 nvmet_parse_passthru_admin_cmd(struct nvmet_req *req)
 int nvmet_passthru_ctrl_enable(struct nvmet_subsys *subsys)
 {
 	struct nvme_ctrl *ctrl;
+	struct file *file;
 	int ret = -EINVAL;
 	void *old;
 
@@ -488,24 +489,29 @@ int nvmet_passthru_ctrl_enable(struct nvmet_subsys *subsys)
 		goto out_unlock;
 	}
 
-	ctrl = nvme_ctrl_get_by_path(subsys->passthru_ctrl_path);
-	if (IS_ERR(ctrl)) {
-		ret = PTR_ERR(ctrl);
+	file = filp_open(subsys->passthru_ctrl_path, O_RDWR, 0);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto out_unlock;
+	}
+
+	ctrl = nvme_ctrl_from_file(file);
+	if (!ctrl) {
 		pr_err("failed to open nvme controller %s\n",
 		       subsys->passthru_ctrl_path);
 
-		goto out_unlock;
+		goto out_put_file;
 	}
 
 	old = xa_cmpxchg(&passthru_subsystems, ctrl->cntlid, NULL,
 			 subsys, GFP_KERNEL);
 	if (xa_is_err(old)) {
 		ret = xa_err(old);
-		goto out_put_ctrl;
+		goto out_put_file;
 	}
 
 	if (old)
-		goto out_put_ctrl;
+		goto out_put_file;
 
 	subsys->passthru_ctrl = ctrl;
 	subsys->ver = ctrl->vs;
@@ -516,13 +522,12 @@ int nvmet_passthru_ctrl_enable(struct nvmet_subsys *subsys)
 			NVME_TERTIARY(subsys->ver));
 		subsys->ver = NVME_VS(1, 2, 1);
 	}
-
+	nvme_get_ctrl(ctrl);
 	__module_get(subsys->passthru_ctrl->ops->module);
-	mutex_unlock(&subsys->lock);
-	return 0;
+	ret = 0;
 
-out_put_ctrl:
-	nvme_put_ctrl(ctrl);
+out_put_file:
+	filp_close(file, NULL);
 out_unlock:
 	mutex_unlock(&subsys->lock);
 	return ret;