lib: logic_pio: Add logic_pio_unregister_range()

Add a function to unregister a logical PIO range.

Logical PIO space can still be leaked when unregistering certain
LOGIC_PIO_CPU_MMIO regions, but this acceptable for now since there are no
callers to unregister LOGIC_PIO_CPU_MMIO regions, and the logical PIO
region allocation scheme would need significant work to improve this.

Cc: stable@vger.kernel.org
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>
diff --git a/lib/logic_pio.c b/lib/logic_pio.c
index d0165c8..9050275 100644
--- a/lib/logic_pio.c
+++ b/lib/logic_pio.c
@@ -99,6 +99,20 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
 }
 
 /**
+ * logic_pio_unregister_range - unregister a logical PIO range for a host
+ * @range: pointer to the IO range which has been already registered.
+ *
+ * Unregister a previously-registered IO range node.
+ */
+void logic_pio_unregister_range(struct logic_pio_hwaddr *range)
+{
+	mutex_lock(&io_range_mutex);
+	list_del_rcu(&range->list);
+	mutex_unlock(&io_range_mutex);
+	synchronize_rcu();
+}
+
+/**
  * find_io_range_by_fwnode - find logical PIO range for given FW node
  * @fwnode: FW node handle associated with logical PIO range
  *