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Message-ID: <9ccdf330-f501-ed5f-f85c-4a5d08cd889a@quicinc.com>
Date: Thu, 25 Apr 2024 12:28:21 +0530
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Subject: Re: [PATCH v2 3/3] wifi: ath12k: Add lock to protect the hardware
 state
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To: Jeff Johnson <quic_jjohnson@quicinc.com>, <ath12k@lists.infradead.org>
CC: <linux-wireless@vger.kernel.org>
References: <20240424065646.1666166-1-quic_periyasa@quicinc.com>
 <20240424065646.1666166-4-quic_periyasa@quicinc.com>
 <833facaa-6b8d-4301-84e1-bef1980f26b6@quicinc.com>
From: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>
In-Reply-To: <833facaa-6b8d-4301-84e1-bef1980f26b6@quicinc.com>
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On 4/25/2024 2:11 AM, Jeff Johnson wrote:
> On 4/23/2024 11:56 PM, Karthikeyan Periyasamy wrote:
>> Currently, hardware state is not protected across the reconfigure
>> operations. However, in single wiphy models, multiple radio/links is
>> exposed as a MAC hardware (ieee80211_hw) through the driver hardware
>> abstraction (ath12k_hw) layer. In such scenario, we need to protect
>> hardware state across the multiple radio/link at the driver hardware
>> abstraction (ath12k_hw) layer. Therefore, introduce a new mutex in
>> the ath12k_hw layer.
>>
>> Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
>>
>> Signed-off-by: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>
>> ---
>>   drivers/net/wireless/ath/ath12k/core.c |  4 ++++
>>   drivers/net/wireless/ath/ath12k/core.h |  6 ++++++
>>   drivers/net/wireless/ath/ath12k/mac.c  | 29 ++++++++++++++++++++++++--
>>   3 files changed, 37 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/wireless/ath/ath12k/core.c b/drivers/net/wireless/ath/ath12k/core.c
>> index a685cfd6fd92..e9aabdb9341c 100644
>> --- a/drivers/net/wireless/ath/ath12k/core.c
>> +++ b/drivers/net/wireless/ath/ath12k/core.c
>> @@ -1048,6 +1048,8 @@ static void ath12k_core_post_reconfigure_recovery(struct ath12k_base *ab)
>>   		if (!ah || ah->state == ATH12K_HW_STATE_OFF)
>>   			continue;
>>   
>> +		mutex_lock(&ah->hw_mutex);
>> +
>>   		switch (ah->state) {
>>   		case ATH12K_HW_STATE_ON:
>>   			ah->state = ATH12K_HW_STATE_RESTARTING;
>> @@ -1078,6 +1080,8 @@ static void ath12k_core_post_reconfigure_recovery(struct ath12k_base *ab)
>>   				    "device is wedged, will not restart hw %d\n", i);
>>   			break;
>>   		}
>> +
>> +		mutex_unlock(&ah->hw_mutex);
>>   	}
>>   
>>   	complete(&ab->driver_recovery);
>> diff --git a/drivers/net/wireless/ath/ath12k/core.h b/drivers/net/wireless/ath/ath12k/core.h
>> index eff1093fbb6e..3e3e157b6c56 100644
>> --- a/drivers/net/wireless/ath/ath12k/core.h
>> +++ b/drivers/net/wireless/ath/ath12k/core.h
>> @@ -634,11 +634,17 @@ struct ath12k {
>>   struct ath12k_hw {
>>   	struct ieee80211_hw *hw;
>>   	struct ath12k_base *ab;
>> +
>> +	/* Protect the write operation of the hardware state ath12k_hw::state
>> +	 * between hardware start<=>reconfigure<=>stop transitions.
>> +	 */
>> +	struct mutex hw_mutex;
>>   	enum ath12k_hw_state state;
>>   	bool regd_updated;
>>   	bool use_6ghz_regd;
>>   	u8 num_radio;
>>   
>> +	/* Keep last */
>>   	struct ath12k radio[] __aligned(sizeof(void *));
>>   };
>>   
>> diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
>> index 8b003c18796d..3dc95d36b6a2 100644
>> --- a/drivers/net/wireless/ath/ath12k/mac.c
>> +++ b/drivers/net/wireless/ath/ath12k/mac.c
>> @@ -5546,10 +5546,13 @@ static void ath12k_mac_wait_reconfigure(struct ath12k_base *ab)
>>   
>>   static int ath12k_mac_start(struct ath12k *ar)
>>   {
>> +	struct ath12k_hw *ah = ar->ah;
>>   	struct ath12k_base *ab = ar->ab;
>>   	struct ath12k_pdev *pdev = ar->pdev;
>>   	int ret;
>>   
>> +	lockdep_assert_held(&ah->hw_mutex);
>> +
>>   	mutex_lock(&ar->conf_mutex);
>>   
>>   	ret = ath12k_wmi_pdev_set_param(ar, WMI_PDEV_PARAM_PMF_QOS,
>> @@ -5664,6 +5667,8 @@ static int ath12k_mac_op_start(struct ieee80211_hw *hw)
>>   
>>   	ath12k_drain_tx(ah);
>>   
>> +	mutex_lock(&ah->hw_mutex);
> 
> since this is always unlocked just before we return, it is a good candidate
> for the cleanup.h functionality. just change this to:
> 	guard(mutex)(&ah->hw_mutex);
> 
> and remove all of the other edits to this function. the mutex will always be
> unlocked when the function returns
> 

sure, will address this comment in the next version of the patch.


>> +
>>   	switch (ah->state) {
>>   	case ATH12K_HW_STATE_OFF:
>>   		ah->state = ATH12K_HW_STATE_ON;
>> @@ -5678,7 +5683,8 @@ static int ath12k_mac_op_start(struct ieee80211_hw *hw)
>>   		ah->state = ATH12K_HW_STATE_OFF;
>>   
>>   		WARN_ON(1);
>> -		return -EINVAL;
>> +		ret = -EINVAL;
>> +		goto err;
>>   	}
>>   
>>   	for_each_ar(ah, ar, i) {
>> @@ -5692,6 +5698,8 @@ static int ath12k_mac_op_start(struct ieee80211_hw *hw)
>>   		}
>>   	}
>>   
>> +	mutex_unlock(&ah->hw_mutex);
>> +
>>   	return 0;
>>   
>>   fail_start:
>> @@ -5700,6 +5708,8 @@ static int ath12k_mac_op_start(struct ieee80211_hw *hw)
>>   		ath12k_mac_stop(ar);
>>   	}
>>   
>> +err:
>> +	mutex_unlock(&ah->hw_mutex);
>>   	return ret;
>>   }
>>   
>> @@ -5762,9 +5772,12 @@ int ath12k_mac_rfkill_enable_radio(struct ath12k *ar, bool enable)
>>   
>>   static void ath12k_mac_stop(struct ath12k *ar)
>>   {
>> +	struct ath12k_hw *ah = ar->ah;
>>   	struct htt_ppdu_stats_info *ppdu_stats, *tmp;
>>   	int ret;
>>   
>> +	lockdep_assert_held(&ah->hw_mutex);
>> +
>>   	mutex_lock(&ar->conf_mutex);
>>   	ret = ath12k_mac_config_mon_status_default(ar, false);
>>   	if (ret && (ret != -EOPNOTSUPP))
>> @@ -5800,10 +5813,14 @@ static void ath12k_mac_op_stop(struct ieee80211_hw *hw)
>>   
>>   	ath12k_drain_tx(ah);
>>   
>> +	mutex_lock(&ah->hw_mutex);
>> +
>>   	ah->state = ATH12K_HW_STATE_OFF;
>>   
>>   	for_each_ar(ah, ar, i)
>>   		ath12k_mac_stop(ar);
>> +
>> +	mutex_unlock(&ah->hw_mutex);
>>   }
>>   
>>   static u8
>> @@ -7848,8 +7865,12 @@ ath12k_mac_op_reconfig_complete(struct ieee80211_hw *hw,
>>   	if (reconfig_type != IEEE80211_RECONFIG_TYPE_RESTART)
>>   		return;
>>   
>> -	if (ah->state != ATH12K_HW_STATE_RESTARTED)
>> +	mutex_lock(&ah->hw_mutex);
> 
> another good candidate for
> 	guard(mutex)(&ah->hw_mutex);

sure, will address this comment in the next version of the patch.

> 
>> +
>> +	if (ah->state != ATH12K_HW_STATE_RESTARTED) {
>> +		mutex_unlock(&ah->hw_mutex);
>>   		return;
>> +	}
>>   
>>   	ah->state = ATH12K_HW_STATE_ON;
>>   	ieee80211_wake_queues(hw);
>> @@ -7904,6 +7925,8 @@ ath12k_mac_op_reconfig_complete(struct ieee80211_hw *hw,
>>   
>>   		mutex_unlock(&ar->conf_mutex);
>>   	}
>> +
>> +	mutex_unlock(&ah->hw_mutex);
>>   }
>>   
>>   static void
>> @@ -8850,6 +8873,8 @@ static struct ath12k_hw *ath12k_mac_hw_allocate(struct ath12k_base *ab,
>>   	ah->ab = ab;
>>   	ah->num_radio = num_pdev_map;
>>   
>> +	mutex_init(&ah->hw_mutex);
>> +
>>   	for (i = 0; i < num_pdev_map; i++) {
>>   		ab = pdev_map[i].ab;
>>   		pdev_idx = pdev_map[i].pdev_idx;
> 

-- 
Karthikeyan Periyasamy
--
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