Felix Fietkau [off-list ref] wrote:

When running out of room in the tx queue after calling drv->tx_prepare_skb,
the buffer list will already have been modified on MT7615 and newer drivers.
This can leak a DMA mapping and will show up as swiotlb allocation failures
on x86.

Fix this by moving the queue length check further up. This is less accurate,
since it can overestimate the needed room in the queue on MT7615 and newer,
but the difference is small enough to not matter in practice.

Signed-off-by: Felix Fietkau <nbd@nbd.name>

2 patches applied to wireless-drivers.git, thanks.

ae064fc0e32a mt76: fix tx skb error handling in mt76_dma_tx_queue_skb
94f0e6256c2a mt76: mt7915: only modify tx buffer list after allocating tx token id

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20210216135119.23809-1-nbd@nbd.name/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches