mi: Add endpoint get/set timeout API

This change introduces an API for querying and modifying the endpoint
timeout. Transports may provide a function for valiating a new timeout
value before setting.

Signed-off-by: Jeremy Kerr <[email protected]>

Author: jk-ozlabs

src/nvme/mi.c

@@ -17,6 +17,9 @@
 #include "mi.h"
 #include "private.h"
 
+static const int default_timeout = 1000; /* milliseconds; endpoints may
+					    override */
+
 /* MI-equivalent of nvme_create_root, but avoids clashing symbol names
  * when linking against both libnvme and libnvme-mi.
  */
@@ -57,13 +60,32 @@ struct nvme_mi_ep *nvme_mi_init_ep(nvme_root_t root)
 	list_node_init(&ep->root_entry);
 	ep->root = root;
 	ep->controllers_scanned = false;
+	ep->timeout = default_timeout;
 	list_head_init(&ep->controllers);
 
 	list_add(&root->endpoints, &ep->root_entry);
 
 	return ep;
 }
 
+int nvme_mi_ep_set_timeout(nvme_mi_ep_t ep, unsigned int timeout_ms)
+{
+	if (ep->transport->check_timeout) {
+		int rc;
+		rc = ep->transport->check_timeout(ep, timeout_ms);
+		if (rc)
+			return rc;
+	}
+
+	ep->timeout = timeout_ms;
+	return 0;
+}
+
+unsigned int nvme_mi_ep_get_timeout(nvme_mi_ep_t ep)
+{
+	return ep->timeout;
+}
+
 struct nvme_mi_ctrl *nvme_mi_init_ctrl(nvme_mi_ep_t ep, __u16 ctrl_id)
 {
 	struct nvme_mi_ctrl *ctrl;

src/nvme/mi.h

@@ -451,6 +451,21 @@ nvme_mi_ep_t nvme_mi_next_endpoint(nvme_root_t m, nvme_mi_ep_t e);
 	     e != NULL;							      \
 	     e = _e, _e = nvme_mi_next_endpoint(m, e))
 
+/**
+ * nvme_mi_ep_set_timeout - set a timeout for NVMe-MI responses
+ * @ep: MI endpoint object
+ * @timeout_ms: Timeout for MI responses, given in milliseconds
+ */
+int nvme_mi_ep_set_timeout(nvme_mi_ep_t ep, unsigned int timeout_ms);
+
+/**
+ * nvme_mi_ep_get_timeout - get the current timeout value for NVMe-MI responses
+ * @ep: MI endpoint object
+ *
+ * Returns the current timeout value, in milliseconds, for this endpoint.
+ */
+unsigned int nvme_mi_ep_get_timeout(nvme_mi_ep_t ep);
+
 struct nvme_mi_ctrl;
 
 /**

src/nvme/private.h

@@ -183,6 +183,7 @@ struct nvme_mi_transport {
 		      struct nvme_mi_resp *resp);
 	void (*close)(struct nvme_mi_ep *ep);
 	int (*desc_ep)(struct nvme_mi_ep *ep, char *buf, size_t len);
+	int (*check_timeout)(struct nvme_mi_ep *ep, unsigned int timeout);
 };
 
 struct nvme_mi_ep {
@@ -192,6 +193,7 @@ struct nvme_mi_ep {
 	struct list_node root_entry;
 	struct list_head controllers;
 	bool controllers_scanned;
+	unsigned int timeout;
 };
 
 struct nvme_mi_ctrl {