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From: Kalle Valo <kvalo@kernel.org>
To: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>
Cc: <ath12k@lists.infradead.org>,  <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH v2 2/2] wifi: ath12k: Introduce the container for
 mac80211 hw
References: <20240112024214.3481840-1-quic_periyasa@quicinc.com>
	<20240112024214.3481840-3-quic_periyasa@quicinc.com>
	<87bk9m7f5g.fsf@kernel.org>
	<839b56fa-9ce8-47f3-768d-b4f32a2041f1@quicinc.com>
Date: Tue, 16 Jan 2024 14:38:20 +0200
In-Reply-To: <839b56fa-9ce8-47f3-768d-b4f32a2041f1@quicinc.com> (Karthikeyan
	Periyasamy's message of "Tue, 16 Jan 2024 10:44:46 +0530")
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Karthikeyan Periyasamy <quic_periyasa@quicinc.com> writes:

>>>   static void ath12k_mac_op_cancel_hw_scan(struct ieee80211_hw *hw,
>>>   					 struct ieee80211_vif *vif)
>>>   {
>>> -	struct ath12k *ar = hw->priv;
>>> +	struct ath12k_hw *ah = ath12k_hw_to_ah(hw);
>>> +	struct ath12k *ar;
>>> +
>>> +	mutex_lock(&ah->conf_mutex);
>>> +
>>> +	ar = ath12k_ah_to_ar(ah);
>>>     	mutex_lock(&ar->conf_mutex);
>>>   	ath12k_scan_abort(ar);
>>>   	mutex_unlock(&ar->conf_mutex);
>>>   +	mutex_unlock(&ah->conf_mutex);
>>> +
>>>   	cancel_delayed_work_sync(&ar->scan.timeout);
>>>   }
>>
>> Do we really need two mutexes? I don't see any analysis about that. And
>> even if we do, I feel that it should be added in a separate patch.
>
> Yes, ah->conf_mutex protect the concurrent mac80211 operation. But
> there is other places like radio/link specific synchronous operation
> (ie MGMT tx wait for the vdev deletion) is needed. To fulfill this
> need, we also need radio/link specific (ar) mutex instead of all link
> (ah) mutex for efficient lock/unlock.

Are there any numbers to show the inefficiency? Anyway, I consider
adding new mutexes as an optimisation which could be done in a separate
patch with proper analysis.

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