wifi: mt76: mt7921s: fix workqueue problem causes STA association fail

The ieee80211_queue_work function queues work into the mac80211
local->workqueue, which is widely used for mac80211 internal
work processes. In the mt76 driver, both the mt76-sido-status and
mt76-sdio-net threads enqueue workers to the workqueue with this
function. However, in some cases, when two workers are enqueued
to the workqueue almost simultaneously, the second worker may not
be scheduled immediately and may get stuck for a while.
This can cause timing issues. To avoid these timing
conflicts caused by worker scheduling, replace the worker
with an independent thread.

Fixes: 48fab5b ("mt76: mt7921: introduce mt7921s support")
Signed-off-by: Wang Zhao <wang.zhao@mediatek.com>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76.h

@@ -609,8 +609,7 @@ struct mt76_sdio {
 	struct mt76_worker txrx_worker;
 	struct mt76_worker status_worker;
 	struct mt76_worker net_worker;
-
-	struct work_struct stat_work;
+	struct mt76_worker stat_worker;
 
 	u8 *xmit_buf;
 	u32 xmit_buf_sz;

drivers/net/wireless/mediatek/mt76/mt7615/sdio.c

@@ -204,8 +204,8 @@ static int mt7663s_suspend(struct device *dev)
 	mt76_worker_disable(&mdev->mt76.sdio.txrx_worker);
 	mt76_worker_disable(&mdev->mt76.sdio.status_worker);
 	mt76_worker_disable(&mdev->mt76.sdio.net_worker);
+	mt76_worker_disable(&mdev->mt76.sdio.stat_worker);
 
-	cancel_work_sync(&mdev->mt76.sdio.stat_work);
 	clear_bit(MT76_READING_STATS, &mdev->mphy.state);
 
 	mt76_tx_status_check(&mdev->mt76, true);

drivers/net/wireless/mediatek/mt76/mt7921/sdio.c

@@ -228,7 +228,7 @@ static int mt7921s_suspend(struct device *__dev)
 	mt76_txq_schedule_all(&dev->mphy);
 	mt76_worker_disable(&mdev->tx_worker);
 	mt76_worker_disable(&mdev->sdio.status_worker);
-	cancel_work_sync(&mdev->sdio.stat_work);
+	mt76_worker_disable(&mdev->sdio.stat_worker);
 	clear_bit(MT76_READING_STATS, &dev->mphy.state);
 	mt76_tx_status_check(mdev, true);
 
@@ -260,6 +260,7 @@ static int mt7921s_suspend(struct device *__dev)
 restore_worker:
 	mt76_worker_enable(&mdev->tx_worker);
 	mt76_worker_enable(&mdev->sdio.status_worker);
+	mt76_worker_enable(&mdev->sdio.stat_worker);
 
 	if (!pm->ds_enable)
 		mt76_connac_mcu_set_deep_sleep(mdev, false);
@@ -292,6 +293,7 @@ static int mt7921s_resume(struct device *__dev)
 	mt76_worker_enable(&mdev->sdio.txrx_worker);
 	mt76_worker_enable(&mdev->sdio.status_worker);
 	mt76_worker_enable(&mdev->sdio.net_worker);
+	mt76_worker_enable(&mdev->sdio.stat_worker);
 
 	/* restore previous ds setting */
 	if (!pm->ds_enable)

drivers/net/wireless/mediatek/mt76/mt7921/sdio_mac.c

@@ -107,14 +107,15 @@ int mt7921s_mac_reset(struct mt792x_dev *dev)
 	mt76_worker_disable(&dev->mt76.sdio.txrx_worker);
 	mt76_worker_disable(&dev->mt76.sdio.status_worker);
 	mt76_worker_disable(&dev->mt76.sdio.net_worker);
-	cancel_work_sync(&dev->mt76.sdio.stat_work);
+	mt76_worker_disable(&dev->mt76.sdio.stat_worker);
 
 	mt7921s_disable_irq(&dev->mt76);
 	mt7921s_wfsys_reset(dev);
 
 	mt76_worker_enable(&dev->mt76.sdio.txrx_worker);
 	mt76_worker_enable(&dev->mt76.sdio.status_worker);
 	mt76_worker_enable(&dev->mt76.sdio.net_worker);
+	mt76_worker_enable(&dev->mt76.sdio.stat_worker);
 
 	dev->fw_assert = false;
 	clear_bit(MT76_MCU_RESET, &dev->mphy.state);

drivers/net/wireless/mediatek/mt76/sdio.c

@@ -481,21 +481,21 @@ static void mt76s_status_worker(struct mt76_worker *w)
 		if (dev->drv->tx_status_data && ndata_frames > 0 &&
 		    !test_and_set_bit(MT76_READING_STATS, &dev->phy.state) &&
 		    !test_bit(MT76_STATE_SUSPEND, &dev->phy.state))
-			ieee80211_queue_work(dev->hw, &dev->sdio.stat_work);
+			mt76_worker_schedule(&sdio->stat_worker);
 	} while (nframes > 0);
 
 	if (resched)
 		mt76_worker_schedule(&dev->tx_worker);
 }
 
-static void mt76s_tx_status_data(struct work_struct *work)
+static void mt76s_tx_status_data(struct mt76_worker *worker)
 {
 	struct mt76_sdio *sdio;
 	struct mt76_dev *dev;
 	u8 update = 1;
 	u16 count = 0;
 
-	sdio = container_of(work, struct mt76_sdio, stat_work);
+	sdio = container_of(worker, struct mt76_sdio, stat_worker);
 	dev = container_of(sdio, struct mt76_dev, sdio);
 
 	while (true) {
@@ -508,7 +508,7 @@ static void mt76s_tx_status_data(struct work_struct *work)
 	}
 
 	if (count && test_bit(MT76_STATE_RUNNING, &dev->phy.state))
-		ieee80211_queue_work(dev->hw, &sdio->stat_work);
+		mt76_worker_schedule(&sdio->status_worker);
 	else
 		clear_bit(MT76_READING_STATS, &dev->phy.state);
 }
@@ -600,8 +600,8 @@ void mt76s_deinit(struct mt76_dev *dev)
 	mt76_worker_teardown(&sdio->txrx_worker);
 	mt76_worker_teardown(&sdio->status_worker);
 	mt76_worker_teardown(&sdio->net_worker);
+	mt76_worker_teardown(&sdio->stat_worker);
 
-	cancel_work_sync(&sdio->stat_work);
 	clear_bit(MT76_READING_STATS, &dev->phy.state);
 
 	mt76_tx_status_check(dev, true);
@@ -644,10 +644,14 @@ int mt76s_init(struct mt76_dev *dev, struct sdio_func *func,
 	if (err)
 		return err;
 
+	err = mt76_worker_setup(dev->hw, &sdio->stat_worker, mt76s_tx_status_data,
+				"sdio-sta");
+	if (err)
+		return err;
+
 	sched_set_fifo_low(sdio->status_worker.task);
 	sched_set_fifo_low(sdio->net_worker.task);
-
-	INIT_WORK(&sdio->stat_work, mt76s_tx_status_data);
+	sched_set_fifo_low(sdio->stat_worker.task);
 
 	dev->queue_ops = &sdio_queue_ops;
 	dev->bus = bus_ops;