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Message-ID:
<TYCPR01MB843742DF3BB41BAC3B97C3C998982@TYCPR01MB8437.jpnprd01.prod.outlook.com>
Date: Mon, 9 Sep 2024 00:27:26 +0800
From: Shengyu Qu <wiagn233@...look.com>
To: Felix Fietkau <nbd@....name>, lorenzo@...nel.org, ryder.lee@...iatek.com,
shayne.chen@...iatek.com, sean.wang@...iatek.com, kvalo@...nel.org,
matthias.bgg@...il.com, angelogioacchino.delregno@...labora.com,
daniel@...rotopia.org, miriam.rachel.korenblit@...el.com,
money.wang@...iatek.com, StanleyYP.Wang@...iatek.com,
meichia.chiu@...iatek.com, chui-hao.chiu@...iatek.com,
johannes.berg@...el.com, quic_adisi@...cinc.com, sujuan.chen@...iatek.com,
allen.ye@...iatek.com, linux-wireless@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc: wiagn233@...look.com, Bo Jiao <bo.jiao@...iatek.com>
Subject: Re: [PATCH v6] wifi: mt76: mt7915: add wds support when wed is
enabled
>> diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/main.c
>> b/drivers/net/wireless/mediatek/mt76/mt7915/main.c
>> index 049223df9beb1..dc4d87e004a0f 100644
>> --- a/drivers/net/wireless/mediatek/mt76/mt7915/main.c
>> +++ b/drivers/net/wireless/mediatek/mt76/mt7915/main.c
>> @@ -745,8 +745,15 @@ int mt7915_mac_sta_add(struct mt76_dev *mdev,
>> struct ieee80211_vif *vif,
>> bool ext_phy = mvif->phy != &dev->phy;
>> int ret, idx;
>> u32 addr;
>> + u8 flags = MT76_WED_DEFAULT;
>> - idx = mt76_wcid_alloc(dev->mt76.wcid_mask, MT7915_WTBL_STA);
>> + if (mtk_wed_device_active(&dev->mt76.mmio.wed) &&
>> + !is_mt7915(&dev->mt76)) {
>> + flags = test_bit(MT_WCID_FLAG_4ADDR, &msta->wcid.flags) ?
>> + MT76_WED_WDS_ACTIVE : MT76_WED_ACTIVE;
>> + }
>> +
>> + idx = __mt76_wcid_alloc(mdev->wcid_mask, MT7915_WTBL_STA, flags);
>> if (idx < 0)
>> return -ENOSPC;
>
> I'd prefer to replace the mt76_wcid_alloc flags argument with an
> explicit start offset argument.
Hi Felix,
I'm not really familiar with mt76 code, just a enthusiast that wants to
make WDS+WED working. So I'm not sure how to do this correctly... Maybe
it's better for you to take over this patch, sorry.
>> @@ -1201,12 +1208,27 @@ static void mt7915_sta_set_4addr(struct
>> ieee80211_hw *hw,
>> {
>> struct mt7915_dev *dev = mt7915_hw_dev(hw);
>> struct mt7915_sta *msta = (struct mt7915_sta *)sta->drv_priv;
>> + int min = MT76_WED_WDS_MIN, max = MT76_WED_WDS_MAX;
>> if (enabled)
>> set_bit(MT_WCID_FLAG_4ADDR, &msta->wcid.flags);
>> else
>> clear_bit(MT_WCID_FLAG_4ADDR, &msta->wcid.flags);
>> + if (mtk_wed_device_active(&dev->mt76.mmio.wed) &&
>> + !is_mt7915(&dev->mt76) &&
>> + (msta->wcid.idx < min || msta->wcid.idx > max - 1)) {
>> + struct ieee80211_sta *pre_sta;
>> +
>> + pre_sta = kzalloc(sizeof(*sta) + sizeof(*msta), GFP_KERNEL);
>> + mt76_sta_pre_rcu_remove(hw, vif, sta);
>> + memmove(pre_sta, sta, sizeof(*sta) + sizeof(*msta));
>> + mt7915_sta_add(hw, vif, sta);
>> + synchronize_rcu();
>> + mt7915_sta_remove(hw, vif, pre_sta);
>> + kfree(pre_sta);
>> + }
>> +
>> mt76_connac_mcu_wtbl_update_hdr_trans(&dev->mt76, vif, sta);
>> }
>>
> In order to update the code based on my latest changes and to fix
> potential race conditions on tx/rx packets during the transition, please
> change to this order:
>
> 1. copy the sta
> 2. allocate a new wcid
> 3. change the wcid index in the copied sta to the newly allocated wcid
> 4. call mcu functions on the duplicate sta for creating the new sta entry.
> 5. use rcu_assign_pointer to point dev->wcid[new_idx] at &msta->wcid
> 6. swap wcid index between real sta and duplicated sta
> 7. rcu_assign_pointer(dev->wcid[orig_idx], NULL)
> 8. synchronize_rcu()
> 9. call mcu functions to delete the duplicate sta's entry (points to old
> wcid after the swap)
> 10. free the duplicated sta
Now, the mt7915_sta_set_4addr function looks like this(__mt76_wcid_alloc
not modified), do you think it's acceptable?
static void mt7915_sta_set_4addr(struct ieee80211_hw *hw,
struct ieee80211_vif *vif,
struct ieee80211_sta *sta,
bool enabled)
{
struct mt7915_dev *dev = mt7915_hw_dev(hw);
struct mt7915_sta *msta = (struct mt7915_sta *)sta->drv_priv;
int min = MT76_WED_WDS_MIN, max = MT76_WED_WDS_MAX;
struct ieee80211_sta *pre_sta;
u8 flags = MT76_WED_DEFAULT;
int temp_idx;
if (enabled)
set_bit(MT_WCID_FLAG_4ADDR, &msta->wcid.flags);
else
clear_bit(MT_WCID_FLAG_4ADDR, &msta->wcid.flags);
if (!msta->wcid.sta)
return;
if (mtk_wed_device_active(&dev->mt76.mmio.wed) &&
!is_mt7915(&dev->mt76) &&
(msta->wcid.idx < min || msta->wcid.idx > max - 1)) {
pre_sta = kzalloc(sizeof(*sta) + sizeof(*msta), GFP_KERNEL);
memmove(pre_sta, sta, sizeof(*sta) + sizeof(*msta));
if (mtk_wed_device_active(&dev->mt76.mmio.wed) &&
!is_mt7915(&dev->mt76)) {
flags = test_bit(MT_WCID_FLAG_4ADDR, &msta->wcid.flags) ?
MT76_WED_WDS_ACTIVE : MT76_WED_ACTIVE;
}
temp_idx = __mt76_wcid_alloc(mdev->wcid_mask, MT7915_WTBL_STA, flags);
((struct mt7915_sta *)pre_sta->drv_priv)->wcid.idx = temp_idx;
mt7915_sta_add(hw, vif, pre_sta);
rcu_assign_pointer(dev->mt76.wcid[temp_idx], &msta->wcid);
temp_idx = msta->wcid.idx;
msta->wcid.idx = ((struct mt7915_sta *)pre_sta->drv_priv)->wcid.idx;
((struct mt7915_sta *)pre_sta->drv_priv)->wcid.idx = temp_idx;
rcu_assign_pointer(dev->mt76.wcid[temp_idx], NULL);
synchronize_rcu();
mt7915_sta_remove(hw, vif, pre_sta);
kfree(pre_sta);
}
mt76_connac_mcu_wtbl_update_hdr_trans(&dev->mt76, vif, sta);
}
Best regards,
Shengyu
> This should allow mgmt tx/rx to work while the sta is being migrated to
> the new wcid entry.
>
> - Felix
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