[PATCH 1/3] nvme-fabrics: introduce existing_ctrl operation

[Max Gurtovoy]

The check if the connection request matches an existing controller is
duplicated in several transports (such as RDMA and TCP). Move it to
common code as optional operation.

Also, this check can be done before creating the controller to simplify
the flow.

Reviewed-by: Israel Rukshin <israelr at nvidia.com>
Signed-off-by: Max Gurtovoy <mgurtovoy at nvidia.com>
---
 drivers/nvme/host/fabrics.c | 7 +++++++
 drivers/nvme/host/fabrics.h | 3 +++
 2 files changed, 10 insertions(+)

diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index ce27276f552d..3d5035331b9f 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -1100,6 +1100,13 @@ nvmf_create_ctrl(struct device *dev, const char *buf)
 	if (ret)
 		goto out_module_put;
 
+	if (ops->existing_ctrl) {
+		if (!opts->duplicate_connect && ops->existing_ctrl(opts)) {
+			ret = -EALREADY;
+			goto out_module_put;
+		}
+	}
+
 	ctrl = ops->create_ctrl(dev, opts);
 	if (IS_ERR(ctrl)) {
 		ret = PTR_ERR(ctrl);
diff --git a/drivers/nvme/host/fabrics.h b/drivers/nvme/host/fabrics.h
index a6e22116e139..587b92575a9b 100644
--- a/drivers/nvme/host/fabrics.h
+++ b/drivers/nvme/host/fabrics.h
@@ -153,6 +153,8 @@ struct nvmf_ctrl_options {
  *			that would go into starting up that fabric
  *			for the purpose of conneciton to an NVMe controller
  *			using that fabric technology.
+ * @existing_ctrl():	optional function pointer that checks if a connection
+ * 			request matches an existing controller.
  *
  * Notes:
  *	1. At minimum, 'required_opts' and 'allowed_opts' should
@@ -170,6 +172,7 @@ struct nvmf_transport_ops {
 	int			allowed_opts;
 	struct nvme_ctrl	*(*create_ctrl)(struct device *dev,
 					struct nvmf_ctrl_options *opts);
+	bool			(*existing_ctrl)(struct nvmf_ctrl_options *opts);
 };
 
 static inline bool
-- 
2.18.1