[params] Use reference counters for form parameter lists

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/params.h

@@ -14,6 +14,8 @@ FILE_LICENCE ( GPL2_OR_LATER );
 
 /** A form parameter list */
 struct parameters {
+	/** Reference count */
+	struct refcnt refcnt;
 	/** List of all parameter lists */
 	struct list_head list;
 	/** Name */
@@ -32,6 +34,43 @@ struct parameter {
 	const char *value;
 };
 
+/**
+ * Increment form parameter list reference count
+ *
+ * @v params		Parameter list, or NULL
+ * @ret params		Parameter list as passed in
+ */
+static inline __attribute__ (( always_inline )) struct parameters *
+params_get ( struct parameters *params ) {
+	ref_get ( &params->refcnt );
+	return params;
+}
+
+/**
+ * Decrement form parameter list reference count
+ *
+ * @v params		Parameter list, or NULL
+ */
+static inline __attribute__ (( always_inline )) void
+params_put ( struct parameters *params ) {
+	ref_put ( &params->refcnt );
+}
+
+/**
+ * Claim ownership of form parameter list
+ *
+ * @v params		Parameter list
+ * @ret params		Parameter list
+ */
+static inline __attribute__ (( always_inline )) struct parameters *
+claim_parameters ( struct parameters *params ) {
+
+	/* Remove from list of parameter lists */
+	list_del ( &params->list );
+
+	return params;
+}
+
 /** Iterate over all form parameters in a list */
 #define for_each_param( param, params )				\
 	list_for_each_entry ( (param), &(params)->entries, list )
@@ -40,7 +79,5 @@ extern struct parameters * find_parameters ( const char *name );
 extern struct parameters * create_parameters ( const char *name );
 extern struct parameter * add_parameter ( struct parameters *params,
 					  const char *key, const char *value );
-extern void destroy_parameters ( struct parameters *params );
-extern void claim_parameters ( struct parameters *params );
 
 #endif /* _IPXE_PARAMS_H */