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 <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20230807171148.210181-8-robdclark@gmail.com
Signed-off-by: Georgi Djakov <djakov@kernel.org>

diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index e15a92a..1afbc4f 100644 (file)
--- a/drivers/interconnect/core.c
+++ b/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);