From: James Smart <jsmart2021@gmail.com>
Date: Fri, 20 Oct 2017 16:17:08 -0700
Subject: nvme-fc: add support for duplicate_connect option
Patch-mainline: v4.15-rc1
Git-commit: 56d5f4f108efd4e439d2320738e2b894af0920bb
References: FATE#323952, FATE#322506

Adds support for the duplicate_connect option. When set to true,
checks whether there's an existing controller via the same host port
and target port for the same host (hostnqn, hostid) to the same
subsystem. Fails the connection request if an existing controller.

Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/nvme/host/fc.c |   33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -2792,6 +2792,33 @@ static const struct blk_mq_ops nvme_fc_a
 };
 
 
+/*
+ * Fails a controller request if it matches an existing controller
+ * (association) with the same tuple:
+ * <Host NQN, Host ID, local FC port, remote FC port, SUBSYS NQN>
+ *
+ * The ports don't need to be compared as they are intrinsically
+ * already matched by the port pointers supplied.
+ */
+static bool
+nvme_fc_existing_controller(struct nvme_fc_rport *rport,
+		struct nvmf_ctrl_options *opts)
+{
+	struct nvme_fc_ctrl *ctrl;
+	unsigned long flags;
+	bool found = false;
+
+	spin_lock_irqsave(&rport->lock, flags);
+	list_for_each_entry(ctrl, &rport->ctrl_list, ctrl_list) {
+		found = nvmf_ctlr_matches_baseopts(&ctrl->ctrl, opts);
+		if (found)
+			break;
+	}
+	spin_unlock_irqrestore(&rport->lock, flags);
+
+	return found;
+}
+
 static struct nvme_ctrl *
 nvme_fc_init_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
 	struct nvme_fc_lport *lport, struct nvme_fc_rport *rport)
@@ -2806,6 +2833,12 @@ nvme_fc_init_ctrl(struct device *dev, st
 		goto out_fail;
 	}
 
+	if (!opts->duplicate_connect &&
+	    nvme_fc_existing_controller(rport, opts)) {
+		ret = -EALREADY;
+		goto out_fail;
+	}
+
 	ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
 	if (!ctrl) {
 		ret = -ENOMEM;