From 2771dc34ddaa313127d6431f23ae4cea26b869b0 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Fri, 16 Sep 2016 18:02:44 +0200 Subject: [PATCH] i2c: add a warning to i2c_adapter_depth() 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 Acked-by: Peter Rosin Acked-by: Peter Zijlstra (Intel) Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 981de21ab814..98fffa3a09f7 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1433,6 +1433,9 @@ 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); -- GitLab