Hi MyungJoo Ham, Based on our understanding of the code, the variable cur_delay stores the old value of devfreq->profile->polling_ms. We also agree that reading from *delay does not need to be protected by the lock. The reason we moved both definitions inside the lock is to maintain the original order of the code. We apologize for the misunderstanding this may have caused. If the read of devfreq->profile->polling_ms is not protected by the lock, the cur_delay that enters the critical section would not store the actual old value of devfreq->profile->polling_ms, which would affect the subsequent checks like if (!cur_delay) and if (cur_delay > new_delay), potentially causing the driver to perform incorrect operations. We believe that moving the read of devfreq->profile->polling_ms inside the lock is beneficial as it ensures that cur_delay stores the true old value of devfreq->profile->polling_ms, ensuring the correctness of the later checks. As for acquiring the lock in the caller, we believe that this is not suitable in this case because it may require introducing a new lock. Furthermore, the function takes a struct devfreq *devfreq as a parameter and accesses devfreq->profile->polling_ms, so holding devfreq->lock prevents devfreq->profile->polling_ms from being modified. Protecting the read operation with devfreq->lock seems natural and ensures that the retrieved value is the real old value of devfreq->profile->polling_ms, which we believe is effective. Thank you for your response, and we welcome further discussion. Qiu-ji Chen
