From 53801d2e762a611d972e91d151df56c3412ca5cf Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Wed, 18 Oct 2023 11:46:13 +0200 Subject: [PATCH] i2c: core: fix lockdep warning for sparsely nested adapter chain When adapters are chained in a sparse manner (with intermediate MFD devices, for instance) the code currently fails to use the correct subclass for the adapter's bus_lock which leads to false-positive lockdep warnings. Fix this by walking the entire pedigree of the device and count all adapters along the way instead of just checking the immediate parent. Signed-off-by: Daniel Mack Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core-base.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 7f30bcceebae..eac90a3cf61a 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -1194,9 +1194,11 @@ static void i2c_adapter_dev_release(struct device *dev) unsigned int i2c_adapter_depth(struct i2c_adapter *adapter) { unsigned int depth = 0; + struct device *parent; - while ((adapter = i2c_parent_is_i2c_adapter(adapter))) - depth++; + for (parent = adapter->dev.parent; parent; parent = parent->parent) + if (parent->type == &i2c_adapter_type) + depth++; WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES, "adapter depth exceeds lockdep subclass limit\n");