On 4/21/2016 10:59 PM, Fugang Duan wrote:
> From: Troy Kisky <troy.ki...@boundarydevices.com> Sent: Friday, April 22,
> 2016 10:01 AM
>> To: netdev@vger.kernel.org; da...@davemloft.net; Fugang Duan
>> <fugang.d...@nxp.com>; lzn...@gmail.com
>> Cc: Fabio Estevam <fabio.este...@nxp.com>; l.st...@pengutronix.de;
>> and...@lunn.ch; trem...@gmail.com; g...@uclinux.org; linux-arm-
>> ker...@lists.infradead.org; johan...@sipsolutions.net;
>> stillcompil...@gmail.com; sergei.shtyl...@cogentembedded.com;
>> a...@arndb.de; holgerschu...@gmail.com; Troy Kisky
>> <troy.ki...@boundarydevices.com>
>> Subject: [PATCH net 1/1] net: fec: update dirty_tx even if no skb
>>
>> If dirty_tx isn't updated, then dma_unmap_single will be called twice.
>>
>> This fixes a
>> [ 58.420980] ------------[ cut here ]------------
>> [ 58.425667] WARNING: CPU: 0 PID: 377 at /home/schurig/d/mkarm/linux-
>> 4.5/lib/dma-debug.c:1096 check_unmap+0x9d0/0xab8()
>> [ 58.436405] fec 2188000.ethernet: DMA-API: device driver tries to free DMA
>> memory it has not allocated [device address=0x0000000000000000] [size=66
>> bytes]
>>
>> encountered by Holger
>>
>> Signed-off-by: Troy Kisky <troy.ki...@boundarydevices.com>
>> Tested-by: <holgerschu...@gmail.com>
>> ---
>> drivers/net/ethernet/freescale/fec_main.c | 8 +++-----
>> 1 file changed, 3 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/freescale/fec_main.c
>> b/drivers/net/ethernet/freescale/fec_main.c
>> index 08243c2..b71654c 100644
>> --- a/drivers/net/ethernet/freescale/fec_main.c
>> +++ b/drivers/net/ethernet/freescale/fec_main.c
>> @@ -1197,10 +1197,8 @@ fec_enet_tx_queue(struct net_device *ndev, u16
>> queue_id)
>> fec16_to_cpu(bdp->cbd_datlen),
>> DMA_TO_DEVICE);
>> bdp->cbd_bufaddr = cpu_to_fec32(0);
>> - if (!skb) {
>> - bdp = fec_enet_get_nextdesc(bdp, &txq->bd);
>> - continue;
>> - }
>> + if (!skb)
>> + goto skb_done;
>>
>> /* Check for errors. */
>> if (status & (BD_ENET_TX_HB | BD_ENET_TX_LC | @@ -1239,7
>> +1237,7 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id)
>>
>> /* Free the sk buffer associated with this last transmit */
>> dev_kfree_skb_any(skb);
>> -
>> +skb_done:
>> /* Make sure the update to bdp and tx_skbuff are performed
>> * before dirty_tx
>> */
>> --
>> 2.5.0
>
> The patch is fine for me.
> Can you review below patch that also fix the issue. It can take much effort
> due to less rmb() and READ_ONCE() operation that is very sensitive for duplex
> Gbps test for i.MX6SX/i.MX7d SOC. (i.MX6SX can reach at 1.4Gbps, i.MX7D can
> reach at 1.8Gbps.)
>
Am I supposed to do anything else to get this patch into net ?
