interconnect: Teach lockdep about icc_bw_lock order

Teach lockdep that icc_bw_lock is needed in code paths that could
deadlock if they trigger reclaim.

Signed-off-by: Rob Clark <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Georgi Djakov <[email protected]>

Author: robclark

drivers/interconnect/core.c

@@ -1041,13 +1041,21 @@ void icc_sync_state(struct device *dev)
 			}
 		}
 	}
+	mutex_unlock(&icc_bw_lock);
 	mutex_unlock(&icc_lock);
 }
 EXPORT_SYMBOL_GPL(icc_sync_state);
 
 static int __init icc_init(void)
 {
-	struct device_node *root = of_find_node_by_path("/");
+	struct device_node *root;
+
+	/* Teach lockdep about lock ordering wrt. shrinker: */
+	fs_reclaim_acquire(GFP_KERNEL);
+	might_lock(&icc_bw_lock);
+	fs_reclaim_release(GFP_KERNEL);
+
+	root = of_find_node_by_path("/");
 
 	providers_count = of_count_icc_providers(root);
 	of_node_put(root);