From: Mika Westerberg <mika.westerb...@linux.intel.com>
Date: Fri, 24 Nov 2017 14:05:36 +0300
> Commit 86dabda426ac ("net: thunderbolt: Clear finished Tx frame bus
> address in tbnet_tx_callback()") fixed a DMA-API violation where the
> driver called dma_unmap_page() in tbnet_free_buffers() for a bus address
> that might already be unmapped. The fix was to zero out the bus address
> of a frame in tbnet_tx_callback().
>
> However, as pointed out by David Miller, zero might well be valid
> mapping (at least in theory) so it is not good idea to use it here.
>
> It turns out that we don't need the whole map/unmap dance for Tx buffers
> at all. Instead we can map the buffers when they are initially allocated
> and unmap them when the interface is brought down. In between we just
> DMA sync the buffers for the CPU or device as needed.
>
> Signed-off-by: Mika Westerberg <mika.westerb...@linux.intel.com>
Applied, thanks.
