mi: Add maximum More Processing Required limit API

This change adds a function to set the maximum time we're prepared to
wait for a response after a More Processing Required message.

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

Author: jk-ozlabs

src/nvme/mi.c

@@ -61,6 +61,7 @@ struct nvme_mi_ep *nvme_mi_init_ep(nvme_root_t root)
 	ep->root = root;
 	ep->controllers_scanned = false;
 	ep->timeout = default_timeout;
+	ep->mprt_max = 0;
 	list_head_init(&ep->controllers);
 
 	list_add(&root->endpoints, &ep->root_entry);
@@ -81,6 +82,11 @@ int nvme_mi_ep_set_timeout(nvme_mi_ep_t ep, unsigned int timeout_ms)
 	return 0;
 }
 
+void nvme_mi_ep_set_mprt_max(nvme_mi_ep_t ep, unsigned int mprt_max_ms)
+{
+	ep->mprt_max = mprt_max_ms;
+}
+
 unsigned int nvme_mi_ep_get_timeout(nvme_mi_ep_t ep)
 {
 	return ep->timeout;

src/nvme/mi.h

@@ -458,6 +458,24 @@ nvme_mi_ep_t nvme_mi_next_endpoint(nvme_root_t m, nvme_mi_ep_t e);
  */
 int nvme_mi_ep_set_timeout(nvme_mi_ep_t ep, unsigned int timeout_ms);
 
+/**
+ * nvme_mi_ep_set_mprt_max - set the maximum wait time for a More Processing
+ * Required response
+ * @ep: MI endpoint object
+ * @mprt_max_ms: Maximum more processing required wait time
+ *
+ * NVMe-MI endpoints may respond to a request with a "More Processing Required"
+ * response; this also includes a hint on the worst-case processing time for
+ * the eventual response data, with a specification-defined maximum of 65.535
+ * seconds.
+ *
+ * This function provides a way to limit the maximum time we're prepared to
+ * wait for the final response. Specify zero in @mprt_max_ms for no limit.
+ * This should be larger than the command/response timeout set in
+ * &nvme_mi_ep_set_timeout().
+ */
+void nvme_mi_ep_set_mprt_max(nvme_mi_ep_t ep, unsigned int mprt_max_ms);
+
 /**
  * nvme_mi_ep_get_timeout - get the current timeout value for NVMe-MI responses
  * @ep: MI endpoint object

src/nvme/private.h

@@ -194,6 +194,7 @@ struct nvme_mi_ep {
 	struct list_head controllers;
 	bool controllers_scanned;
 	unsigned int timeout;
+	unsigned int mprt_max;
 };
 
 struct nvme_mi_ctrl {