Re: [PATCH v2] sh_eth: unmap DMA buffers when freeing rings

[David Miller <davem@davemloft.net>]

From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Date: Wed, 19 Apr 2017 22:09:51 +0300

> On 04/17/2017 11:10 PM, David Miller wrote:
> 
>>> The DMA API debugging (when enabled) causes:
>>>
>>> WARNING: CPU: 0 PID: 1445 at lib/dma-debug.c:519
>>> add_dma_entry+0xe0/0x12c
>>> DMA-API: exceeded 7 overlapping mappings of cacheline 0x01b2974d
>>>
>>> to be  printed after repeated initialization of the Ether device, e.g.
>>> suspend/resume or 'ifconfig' up/down. This is because DMA buffers
>>> mapped
>>> using dma_map_single() in sh_eth_ring_format() and sh_eth_start_xmit()
>>> are
>>> never unmapped. Resolve this problem by unmapping the buffers when
>>> freeing
>>> the descriptor rings; in order to do it right, we'd have to add an
>>> extra
>>> parameter to sh_eth_txfree() (we rename this function to
>>> sh_eth_tx_free(),
>>> while at it).
>>>
>>> Based on the commit a47b70ea86bd ("ravb: unmap descriptors when
>>> freeing
>>> rings").
>>>
>>> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
>>
>> Applied, thanks.
> 
>    Please don;t forget to send it to -stable.
>    The bug seems to be there from the very beginning.

Ok, queued up.