mt76: mt7915: drop zero-length packet to avoid Tx hang

Hardware wouldn't add LLC-SNAP when skb->data_len is 0, which causes
Tx hang, so add a check to drop this kind of packet.

Tested-by: Bo Jiao <bo.jiao@mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
index dab46bd..ecabab7 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
@@ -942,6 +942,9 @@ int mt7915_tx_prepare_skb(struct mt76_dev *mdev, void *txwi_ptr,
        int id, i, nbuf = tx_info->nbuf - 1;
        u8 *txwi = (u8 *)txwi_ptr;
 
+       if (unlikely(tx_info->skb->len <= ETH_HLEN))
+               return -EINVAL;
+
        if (!wcid)
                wcid = &dev->mt76.global_wcid;