From: Mika Westerberg <mika.westerb...@linux.intel.com> Date: Thu, 9 Nov 2017 13:46:28 +0300
> When Thunderbolt network interface is disabled or when the cable is > unplugged the driver releases all allocated buffers by calling > tbnet_free_buffers() for each ring. This function then calls > dma_unmap_page() for each buffer it finds where bus address is non-zero. > Now, we only clear this bus address when the Tx buffer is sent to the > hardware so it is possible that the function finds an entry that has > already been unmapped. > > Enabling DMA-API debugging catches this as well: > > thunderbolt 0000:06:00.0: DMA-API: device driver tries to free DMA > memory it has not allocated [device address=0x0000000068321000] > [size=4096 bytes] > > Fix this by clearing the bus address of a Tx frame right after we have > unmapped the buffer. > > Signed-off-by: Mika Westerberg <mika.westerb...@linux.intel.com> Applied, but assuming zero is a non-valid DMA address is never a good idea. That's why we have the DMA error code signaling abstracted.
