[PATCH] wifi: mt7915: disable rx napi when removing device

Unloading the mt7915e module with a MT7916 triggers multiples WARN in
__netif_napi_del_locked() and in page_pool_disable_direct_recycling()
because the driver does not disable the napi before destroying it.

This is troublesome since on MT7916 it is required to unload the module
and reinsert it with a different enable_6ghz parameter to change the
frequency.  The system generally becomes unstable after reinserting the
module.

Fix it by disabling rx napi inside mt7915e itself, even through napi rx is
enabled in the mt76 generic code.  Disabling it in the mt76 generic code
was previously attempted and reverted because napi was disabled too
late and rx handlers could access freed structures.  Note that the tx
side is enabled and disabled by the mt76 generic code.

It is disabled in mt7915_stop_hardware() since, unlike
mt7915_unregister_device(), is it also called in the probe path if an
error happens after rx napi is enabled.

Fixes: e57b7901469f ("mt76: add mac80211 driver for MT7915 PCIe-based chipsets")
Signed-off-by: Nicolas Cavallari <[email protected]>
---

Back from vacation.
This depends on https://lore.kernel.org/linux-wireless/[email protected]/T/ being applied.
Sorry for the trouble.
 drivers/net/wireless/mediatek/mt76/mt7915/init.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/init.c b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
index ca46a203aa48..c8e389db63a7 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
@@ -1238,6 +1238,12 @@ static void mt7915_unregister_ext_phy(struct mt7915_dev *dev)
 
 static void mt7915_stop_hardware(struct mt7915_dev *dev)
 {
+	int i;
+
+	mt76_for_each_q_rx(&dev->mt76, i) {
+		if (!mt76_queue_is_wed_rro(&dev->mt76.q_rx[i]))
+			napi_disable(&dev->mt76.napi[i]);
+	}
 	mt7915_mcu_exit(dev);
 	mt76_connac2_tx_token_put(&dev->mt76);
 	mt7915_dma_cleanup(dev);

base-commit: 4df22710a77d2365e56d720bc4106e54c1dfa2ff
prerequisite-patch-id: 7d4fbb111c901db1b996617c056803d005844046
-- 
2.55.0