Commit 53801d2e authored by Daniel Mack's avatar Daniel Mack Committed by Wolfram Sang
Browse files

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: default avatarDaniel Mack <daniel@zonque.org>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent 702c0dd7

drivers/i2c/i2c-core-base.c

+4 −2
Original line number Diff line number Diff line
@@ -1194,8 +1194,10 @@ 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)))

	for (parent = adapter->dev.parent; parent; parent = parent->parent)

		if (parent->type == &i2c_adapter_type)

			depth++;



	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,