diff mbox

[v2,3/4] i2c: add a warning to i2c_adapter_depth()

Message ID 1474041765-17818-4-git-send-email-bgolaszewski@baylibre.com
State Accepted
Commit 2771dc34ddaa313127d6431f23ae4cea26b869b0
Headers show

Commit Message

Bartosz Golaszewski Sept. 16, 2016, 4:02 p.m. UTC
This routine is only used together with lockdep for nested locking.
The number of lock subclasses is limited to 8 as defined in lockdep.h

Emit a warning if the adapter depth exceeds the maximum number of
lockdep subclasses.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

---
 drivers/i2c/i2c-core.c | 3 +++
 1 file changed, 3 insertions(+)

-- 
2.7.4

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diff mbox

Patch

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index c9b8df8..75cefa8 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1342,6 +1342,9 @@  unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 	while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 		depth++;
 
+	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
+		  "adapter depth exceeds lockdep subclass limit\n");
+
 	return depth;
 }
 EXPORT_SYMBOL_GPL(i2c_adapter_depth);